HomeMy WebLinkAboutAPA4133Volume 12 fV.rp .llJ o. (
Project W-3-R-12
lv'.OOSE MANAGEMENT STUDIES
Work Plan A Job No. 1-7
April 1, 1958
Volume 12 Number 1
JOB COMPLETION REPORTS
Project W-·3-R-12 Alaska January 31~ 1958
Urban C. Nelson
Wildlife Investigations
Work Plan A
MOOSE MANAGEMENT STUDIES
Personnel
Robert F. Scott" Supervisor Game Restoration
Da:Y.id R. Kleiriv Wildlife Management Biologist
Sigurd T. Olson, " 11 "
Robert A. Rausch 11 " 11
Ronald 0. Skoog, 11 11 11
Peter E. K. Shepherd, Biological Aid
Dustin L. Sloan, II II
Chief, Fish and Game Restoration
Clarence J. Rhode
Executive Officer
Alaska Game Commission
Not for Publication
(The results described in these reports are preliminary and often fragmentary
in nature. Conclusions are subject to change with further investigation and
interpretation.)
CONTENTS
Job No. Title .Page
Summary i
1 Herd Composition Surveys--Susitna and Copper
River Valleys. . ....•.•.•.. ~ . . . . . 1
4 Distribution, Movements and Dynamics of the
Railbelt Moose Populations . . • . • . • . . 28
5 (W-3-R-11) Food Habits of Railbelt Moose. . 110
5 (W-3-R-12) Sampling of Kill by Hunters 117
6 Herd Composition in Interior Alaska . 121
7 Stikine River Valley Aerial Surveys . 134
SUMMARY
Job No. 1--Herd Composition Surveys--Susitna and Copper River Valleys
Sex and age composition cotints o:Cmoose populations inhabiting
the Lower Susitna-Matanuska Valley and the Upper Susitna-Copper
River Valleys were conducted in October, November and December
of 1957 with the following re~ult~:' . -.
1. Four thousand seven hundred sixty moose were tallied in
_ 41. 4 flying hours spent actually counting moose.
2. Productivity in both areas is good with an average of
approximately 43 calves per 100 cows.
3. Young bull survival varies greatly from one local population
to another. The factors affecting this survival are hunting
and probably local environmental conditions.
4. The effects of hunting are reflected by the bull:cow ratios.
These reveal that in areas accessible by road or to tracked
vehicles the bull segment of the population is rapic;lly reduced.
This reduction, however, has not been demonstrated to affect
the pregnancy rate of the cows; thus, the hunting of bulls only
does not control herd size.
5. Experimental counts made during the period of rut indicate a
more homogeneous distribution of the various sex and age
components of a moose population at that time. This is
advantageous for sampling purposes.
Job No. 4--Distribution, Movements and Dynamics of the Railbelt .
Moose Populations.
A study of the railroad-moose conflict in the Lower Susitna Valley
area was conducted from January 3, 1956, through May 15, 1956, and
from November 1956 through June 15, 1957. A study of moose
population dynamics was conducted in conjunction with the railroad-
moose study.
The problem is created by the combination of the following factors:
(1) an abundant moose population, {2) deep snow, and {3) large quantities
of winter moose browse along and adjacent to the right-of-way.
i
The critical kill area is between Houston (Mile Post 172) and
Talkeetna (Mile Post 226), a distance of 54 miles~
In. December 1956 a system for reporting all railroad killed moose
was devised.
Two hundred twenty-five moose were report~d killed in 1955-56,
and 93 in 1956-57. The reporting system is not accurate. The adjusted
total kill was 366 and 179,. respectively.
Several temporary moose saving technics, suggested in 1955-56,
were evaluated in 19 56-:-57. The following are -yvorthy of implementation:
( 1) daylight train operation through criti'cal areas, and (2) redl].ced train
speed through critical areas.
Understanding the factors influencing seasonal moose movements
is believed to be the key to formulating plans for keeping moose away
from the right-of-way.
Some moose populations inhabiting the Lower Susitna Valley exhibit
seasonal altitudinal migrations. The magnitude and extent of these
migrations are not fully understood and warrant further investigation.
Bulldozed trails and feed yards, as a means of keeping moose off
the right-of-way, were experimented with and found partially successful.
Moose guards were tested, but no definite conclusions are drawn.
Approximately 40-45, 000 pounds of moose meat were salvaged
and distributed to charitable institutions in 1956-57. This represents
80-90 percent of all salvable meat and an increased salvage efficiency
of 100 percent over 1955-56.
The direct cost of the moose problem to the railroad over the past
ten years is not known, but has amounted to thousands of dollars
annually.
The moose populations of the Lower Susitna Valley are probably
the most valuable herds in Alaska. Future research must be directed
towards goals which will benefit both the railroad and the moose.
The study of moose population dynamics revealed the following
information:
1. Yearling bulls (16-18 months) are sexually mature.
ii
2. Spermatozoa, presumably viable, are present in the
epididymis from August to December.
3. Most cows breed first at 28-30 months of age, although
. a few yearling cows do breed.
4. Eighty percent of the cows in this population breed during
a 15,-day period inlate September and early October.
5. Fifty percent of the cows have calves by late May.
6. One hundred twenty-four sets of lungs were examined for
the presence of hydatid cysts, Echinococcus granulosus;
25, or 20 percent, were infected.
7. Ninety-eight .cows were examined for pregnancy data;
87 of 93, or 94 percent, Age Class II or above were
pregnant.
8. Weights and measurements of 69 fetuses and 83 calves
and adults are presented.
9. Age determinations made on the mandibular teeth. of
240 railroad killed moose revealed that there is a
predominance of "middle" and old age females and that
sex selective mortality factors probably affect males
excessively.
Job No. 5~,-(W-3-R-11) Food Habits of Railbelt Moose
Rumen content samples from 122 moose killed by trains between
Mile Posts 172 and 231 on the Alaska Railroad during the winters of
1955-56 and 1956-57 were analyzed. Only the gross particles, an
average of 5 percent of each sample, were considered. This analysis
revealed the following: (1) seventeen food items were identified;
(2) willow, birch and aspen comprised 97 percent of the identifiable
food material; (3) moose ate more willow during 1956.57, possibly
due to lesser snow accumulations; and (4) until some technique for
identifying the small food particles, which comprise about 95 percent
of an average rumen content sample, is devised the validity of the
present technique is questionable.
iii
Job No. 5--(W-3-R-12) Sampling of Kill by Hunters
The 1957 moose hunting season can be summarized as follows:
1. Twelve percent of 2, 075 hunters checked were successful.
2. Two hundred ninety-five moose were checked; interviews with
guides and outfitters revealed 300 additional hunter kills for
a total known kill of approximately 600.
3. Fifty-five percent of the moose checked were yearlings.
4. . Ninety percent of the moose checked in the Matanuska Valley
were yearlings.
5. Yearlings, due to habitat preference, may be· more susceptible
to hunters.
Job No. 6=-Herd Composition in Interior Alaska
Aerial composition counts were made in three specific areas subject
to hunting: the Tanana. Valley, Fortymile, and the lower Koyukuk Valley.
Six hundred nine moose were counted in 19.8 hours for an. average of
30.7 moose sighted per hour. The sex and age data are summarized
as follows:
Tanana Valley: The calf:cow ratio decreased from 47:100 in 1956
to 42:100 in 1957. Survival of bull calves to yearlings indicated 35
percent mortality. The bull:cow ratio of 68:100 indicated light hunting
pressure.
Fortymile: The calf:cow ratio decreased from 53:100 in 1956 to
46:100in 1957. Survival of bull calves to yearlings indicated 20 percent
mortality. The bull :cow ratio of 91:100 indicates light hunting pressure;
however, it is believed that a disproportionate samplingof bulls may
have occurred.
Koyukuk: The calf:cow ratio was 67:100 indicating a high level
of productivity. Data from 1956 were not available to determine calf
survival. The young bull:bull calf ratio of 48:100, however, suggested
higher mortality than in other areas; perhaps due to heavy wolf
predation the previous winter. The bull:cow ratio of 80:100 indicated
light hunting pressure.
iv
The calf percentage of the total herd continues at 20 and 19 percent
for the Tanana Valley and Fortymile respectively. These ratios have
not changed since 1954. In the Koyukuk, there were 28 percent calves
in 1957 as compared to 36 percent in 1954.
It is apparent that the moose populations in the Tanana and
Fortymile are relatively stable and are not being affected adversely
by the present hunting pressure. The Koyukuk moose herd also appears
to be in healthy condition despite unusually heavy wolf predation during
the winter of 1957.
Job No. 7-""'Stildne River Valley Aerial Surveys
Sex and age composition counts were made from the air in the
Stikine River Valley in the fall of 1957. The population continues to
show good productivity and a youthful age structure. Data summarizing
the harvest of moose by hunters are given.
v
JOB NO. 1--Herd Composition Surveys--Susitna and Copper River
Valleys
PERIOD COVERED: September 1, 1957, to December 15, 1957
ABSTRACT
Sex andage composition counts of moose populations inhabiting
th'e 14ower Susitna-Matanuska Valley and the Upper Susitna-Copper
River Valleys were conducted in October, November and December
of 1957 with the following results: -.
-L . Four thousand seven hundred sixty moose were tallied in
_ 41. 4 flying hours spent actually counting moose.
2. Productivity in both areas is good with an average of
approximately 43 calves per 100 cows.
3. · Young bull survival varies greatly from one local population
to another. The factors affect;J:lg this survival are hunting
.. and probably local environmental conditions.
4. The effects of hunting are reflected by the bull;cow .ratios.
These reveal that in areas.. accessible by road or to tracked ..
vehicies the bull segment of the population is rapidly reduced.
This· reduction, however, has not been demonst,rated to affect
the pregnancy rate of the cows; thus, the hunting of bulls only
does not -control herd size.
5. Experimental counts made during the period of rut indicate a
more homogeneous distribution of the various sex and age
components of a moose population at that time. This is
advantageous for sampling purposes.
OBJECTIVES
To determine age and sex composition of identifiable local moose
populations as an indication of relative productivity, survival, and
effects of hunting.
TECHNIQUES USED
Coverage
Aerial surveys to determine sex and age composition of local
identifiable moose populations were conducted principally during the
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months of November and December. The lack of adequate snow
cover earlier altered the original plans, which were to make the
counts during the period of rut in early October. Experimental
flights to test the feasibility of sex and age composition counts during
the period of rut were made on October 8, 9, and 10 in the Maclaren
River, Clear Creek, and Upper Susitna River areas. Snow cover
varied from traces at elevations below 2000 feet to complete above
3000 feet. The Upper Susitna and Copper River Valleys were
surveyed between the 6th and 15th of November using Supercub
aircraft. The pilots were Burkholder, Predator Control, and Thayer,
Game Management. Flying time, actually spent counting moose,
totaled 22. 1 hours.
Snow cover in the Lower Susitna River Valley was not adequate
for counting until late November. These areas were covered between
November 15th and December 12th. Again Supercubs were used and
the pilots were Switzer of Game Management and Wardleigh of the
Aircraft Division. Flying time spent actually counting moose totaled
19. 3 hours.
The counts were made within each predetermined local area from
an altitude of 300 to 600 feet depending upon terrain, ground cover, and
moose visibility factors, principally light and snow conditions. Each
moose seen was inspected and assigned to a sex and age category. If
doubt concerning its category existed, a low level inspection pass
was made. Neither total counts nor systematic samples were
practicable due to the great area involved; however, an attempt was
made to spend a proportionate amount of time counting in each cover
type and at the various altitudinal levels within the local area. Since
the sex and age distribution patterns of the various moose populations
were hot known prior to counting, this technic unfortunately does not
always produce a truly representative sample. As more knowledge
of population characteristics accumulates, it is hoped that a solution
to this problem will be found.
Data Recorded
Moose sex and age determination by aerial observers is limited
to five categories:
I. Young bulls--bulls with spike or forked antlers, usually with
little or no palm development. These animals are predominantly
"yearlings'', approximately eighteen months old, but there is
some overlap in ages.
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2. Medium bulls--bulls having some palm development, but
not massive appearing. Probably two and three year olds.
This category's most useful function is to create an
awareness of the size differential between young and adult
bulls. It does not provide clear-cut data useful in
determining population trends. Animals in this category
were considered as adult males in calculating sex and age
ratios.
3. Adult bulls--all bulls having greater antler development than
the preceding age category.
4. Cows--all cows, including yearlings.
5. Calves--young of the year, generally five to seven months
old when the counts are made.
Methods of Analysis
The data from the 19 57 sex and. age composition counts were
analyzed to determine current productivity, survival, and effects of
hunting in each identifiable population and for the moose herds in
general. These indicators of population status were first described
in the 1956 P-R Quarterly Report, 10(3):7-ll. and are defined below.
Each of them is evaluated by examining one or more indices provided
by the apllropriate sex or age ratios.
Productivity--is defined to include both the initial incidence of
live births to females in the population, and also the subsequ~nt
survival of these young to the date of the aerial count about six months
later .. The most significant index used.is the ratio of calves per 100
cows.
Another indicator of productivity is the ratio of twins per 100 cows
with. calves. The significance of this index is not fully understood at
present. In fact. the reliability of the ratio itself has been seriously
questioned. Nevertheless. in certain areas the ratio of twins per
100 cows with calves approac.hes 25 per 100 and adds a significant
number of individuals to the herd. In some areas, such. as the
Koyukuk, high incidence of twinning is concurrent with excellent
productivity; in others, such as the Kahiltna Flats and Susitna-Beluga
Mountains areas, productivity appears very good, but not any greater
than in the Matanuska Valley area which has a low incidence of
twinning as revealed by the 1957 fall counts.
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The variance in observed twinning rates may reflect a number
of survival factors rather than differences in initial rates of twinning.
In the Matanuska Valley examination of nearly 100 cows during the
months when cows are normally pregnant showed 27 sets of twins
per 100 pregnancies, yet the 1957 fall aerial counts showed only
nine sets of twins per 100 cows with calves. This suggests that in
this area mortality rates for twins are greater than they are for
singletons.
The reasons for certain other areas having higher ratios of
twins are not known but th~se may reflect better survival of twins or
a higher initial incidence of twinning due to environmental conditions
or a different population age structure.
The principal index to productivity is the ratio of calves per
100 cows. In comparing productivity trends from year to year, and
by areas, it is believed that descriptive terms indicating the general
trends are more meaningful than the numerical ratios; for this reason
the terms poor, fair, good, and excellent are used in the general
discussion of productivity in this report. These terms correspond
to the following numerical values~
Pocn---------""---below 20 calves per 100 cows
Fair-------------20-35 calves per 100 cows
Good-------------36-50 calves per 100 cows
Excellent---------more than 50 calves per 100 cows
It should be remembered that these t~rm.s relate only to
productivity at approximately six months as measured by the
calf:cow ratio and they do not necessarily indicate the overall
well-being of the herd. A population having poor productivity may
have excellent survival and be increasing; conversely a population
may have excellent productivity, poor survival. and be decreasing.
Survival--is de.fin.ed.as su;t;yiv~l of the c;alves rec;orded on the
ann\lal sex and age c~U:~t~,.to :ap.P~g~i~~tely the same date one year
later--i.e, , survival between. approximately 6 and 18 months, of age.
Two ratios may be used as indices, both m.e~suring survival but
using different &egrnents of the population as compar,ison, l?.a,ses. In
the first, .the ratio of young (Yearfing) bulls per 100 bull calves
indicates survival to 18 months. Here it is nece;Ssary to assume
that calf productiQ:Q> remains constant t;r;om year to year and that
calves have a 1:1 sex ratio. Sex ratia.s of calf moose at or before
birth indicate a slight preponderance of males, but the difference is
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..
not great enough to seriously affect the index. Calf production,
however. may vary considerably from year to year in some areas.
causing an error in the index.
The second index to survival is the ratio of young bulls per 100
cows as compared to the previous year's ratio of bull calves per
100 cows. Theoretically, the difference between these ratios
represents mortality occurring during the period between approximately
6 and 18 months; however. exact percentages obtained from these
methods should not be allowed to imply a degree of accuracy greater
than one can obtain until more of the variables in aerial counting can
be evaluated.
Cows are probably the most constant segment of moose
populations in Alaska, because they are': not hunted, and it is
therefore advantageous to use them as a base for comparison. The
use of the female population segment as a base for the two ratios
used to obtain this index to survival assumes that natural mortality
of adult females is approximately equal to the annual recruitment of
yearling females which are counted as adult cows by aerial observers.
In popvJ.ations experiencing either a rapid increase or decrease the
describ€1d index will be biased'. However. the populations in south
central Alaska appear to be eitlier nearly stable or increasing
slightly and the index is believed to portray a reliable trend providing
that the various sex and age components of each population are
sampled proportionately.
It is possible. but not considered necessary at present. to work
with only those females two years and older. This is accomplished
by subtracting a number equal to the total young bulls counted, from
the total females counted. This method assumes a 1:1 sex ratio of
yearling moose and provides an estimate of the number of cows two
years or older. The previous year's mortality is offset by the
addition of last year's yearlings to the base or comparison segment
of the female population. This method provides an older and perhaps
more stable age group for comparison purposes but does not provide
for differential sex survival rates to two years,, and in some areas
hunting is a major decimating factor to yearling bulls. This would
cause a significant error. in this index in the areas experiencing intense
hunting pressure.
Another indicator of survival, which must be carefully interpreted
where hunting is a survival factor, is the young bull~adult bull ratio.
-5=
Effects of hunting--is defined as the extent to which hunting
reduces the male segment of the population and is measured
primarily by the ratio of bulls per 100 cows. Another index is the
ratio of young bulls per 100 adult bulls. Hunting. tends to lower both
the number and average age of the bull segment of the population;
thus the yearlings constitute a greater portion of the bull population
as hunting pressure increases.
FINDINGS
Sex and Age Composition of the
Lower Susitna Valley Moose Populations
The general area of the Lower Susitna Valley is illustrated in
Figure No. 1. It includes th.e drainage of the Big and Little .Susitna
Rivers from the Talkeetna and Kahiltna Rivers to Cook Inlet. Several
additional populations adjacent to. Anchorage are also included in the
area surveyed.
These areas support some of Ala$lta.~s most abundant, ac(;essible
and valuable moose populations,. as well as some of the least .
accessible. Whenever possible the "are~s outlined in Figure No. 1
represent identifiable populations. Identifiable populations in most
instances refer to specific geographic t~.nits which are believed to
support a resident moose population. The Matanuska V~lley and
Willow areas represent local identifiable populations which have
been studied for several y-ears. The basis for classifying these as
identifiable populations stems from these studies which.are reported
on in another section of this report, and also in the 1956 P-R
Quarterly Report, 11. (2):19-22.
The areas covered are as follows~ Matanuska Valley, above and
below timberline, Willow, Susitna Flats, Kashwitna, Kahiltna Flats,
Susitna and Beluga Mountains, Eagle IUver, Peters Creek, Ship Creek,
and Fo:rt Richardson.
Each population indicato:r is discussed separately below, as it
applies to the general area and to certain local areas.
Productivity
Productivity throughout the Lower Susitna Valley and Anchorage
areas is considered good. The combined and weighted average
calf:cow ratio for the entire area is 44 calves per 100 cows
(Table No. 3:}, This compares favorably with the 1956 average which
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Figure No. 1. Moose populations in. the Lower Susitna Valley and Anchorage
areas.
was 40 calves per 100 cows (Table No. 8). The calf;cow ratios
are remarkably similar in the various local populations comprising
this general area, with the exception of the Willow and Kashwitna
areas which have calf:cow ratios of 35 and 34 calves per 100 cows
respectively. The Willow area has had relatively low productivity
for the past three years, averaging about 30 calves per 100 cows for
this period. The reasons for this seemingly lesser p:poductivity are
not completely understood, but it is believed to reflect survival
:rather than a lower initial production of calves. Previous work in
this area has indicated that 90 percent o£ all cows two years old and
older are successfully bred. This area lies in a deep snow belt and
is also believed to have insufficient winter browse during winters
having deep accumulations of snow. The combination of deep snow
and limited winter brow.se may adversely affect calf vitality at birth
or the ability of the females to care for their calves. Data obtained
from the annual fall sex and age composition counts suggests a
correlation between productivity and the severity of the previous
winter. The winters of 1954-55 and 1955-56 were particularly severe
a:nd productivity as indicated by the fall aerial counts was only fair
in the .Willow area. The winter of 1956-57 was about normal and
productivity in the Willow area increased from 27 calves per 100 cows
in 1956 to 35 per 100 in 1957. This same correlation exists in the
Matanuska. Valley area where the winter of 1954-55 was severe and
the 1955 fall counts show a calf:cow average of approximately 34 calves
per 100 cows. The 1955-56 and 1956-57 winters were not particularly
severe in the Matanuska Valley and the calf:cow ratios were 53 and
50 calves per 100 cows respectively. Quantitative data illustrating
the mortality factors responsible for the differential calf survival in
the Willow and Matanuska areas are needed~
The incidence of twinning in the Lower Susitna Valley and Anchorage
areas, unlike the calf:cow ratio, is quite variable. The ratio of twins
per 100 cows with calves varies from a low of 4 per 100 in the Willow
and Kashwitna areas to a high of 23 per 100 in the Kahiltna area. The
problems of interpreting the significance of twins are discussed in the
section under techniques and are not elaborated upon here.
Survival
Survival of young bulls in the Lower Susitna Valley and Anchorage
areas is poor. The 1956 bull calf:cow ratio was 20 per 100 and the
comparable ratio, young bulls per 100 cows, in 1957 is 7 per 100
(Table No. 7). This indicates that more than 50 percent of last year's
bull calves either failed to overwinter or were removed by hunting
this past season. Examination of survival by area (Table No. 7)
-8-
reveals that young bull survival varies greatly. The areas that are
accessible and receive great hunting pressure, notably the Willow,
Matanuska and Anchorage areas, have young bull~cow ratios of
about 5 per 100. When this ratio is compared with the bull calf~cow
ratio of the same areas in 1956 a mortality of 70 to 90 percent is
indicated and hunting is probably the most important decimating
factor. In areas where hunting is the most important survival
factor, survival as measured by the present indices refers only to
the male segment of the population. Survival of females may be
excellent in the areas where the present data indicate a young bul1
mortality of 70-90 percent by 18 months. Unfortunately, at present
there is no index for measuring female survival in heavily hunted
populations.
In the more inaccessible areas such as the Kahiltna Flats and
the Susitna and Beluga Mountains area, survival of young bulls
appears reastmably good.
The Kashwitna area again is unique in that while hunting pressure
is very light survival of young bulls is less than 50 percent. The
reasons for this seemingly great mortality of young bulls from 6 to
18 months of age in the Kashwitna area are not known but the
climatological and winter browse conditions which were discussed
earlier may also apply to this age category.
The Effects of Hunting
In order to more effectively demonstrate the effects of hunting
on the bull segment of th.e various populations and because hunting
pressure varies in-direct proportion to accessibility, certain of the
areas experiencing different levels of hunting pressure are discussed
separately.
Matanuska Valley. The Matanuska Valley represents an area
subjected to nearly unlimited accessibility by car and foot in the
lowlands and corresponding accessibility to swamp buggies and
tracked vehicles in the timberline areas. This area has an overall
bull~cow ratio of 8 per 100. The bull~cow ratio has declined steadily
for a number of years. -This ratio below timberline was 7, 5, and
3 per 100 in 1955, 1956, and 1957, respectively. The timberline
counts for the same period were 25, 18,. and 15 per 100, respectively.
These figures indicate unusual hunter efficiency in harvesting bulls.
This past fall 6.62 moose were included in the Matanuska area sample;
only 32 were males, of which 20 were yearlings. There is no
indication that this harvest of males has in any way lowered the
-9-
annual calf crop. In all probability the hunter harvest will not
significantly reduce the bull percentage below its present level
because the principle of diminishing returns seems to apply to
hunting as it does to other fields of endeavor.
Willow Area. The Willow area has been hunted intensively for
a number of years and the bull~cow ratio of 28 per 100 reflects this
utilization. The .road system in this area is not as extensive as in
the Matanuska Valley nor are the timberline areas as ac·cessible to
swamp buggies or tracked vehicles. Consequently9 at present. bulls
are more numerous in this area.
Susitna Flats. The bull~cow ratio is 43 per 100. The young
bull:adult bull ratio is 69 per 100. This area is accessible by air
only. but its dose proximity to Anchorage makes it a favored hunting
area for local plane owners. Although aerial hunting pressure is
great 9 the bull :cow ratio has remained quite good from a hunter
standpoint. even though trophy bulls are relatively few.
Kashwitna Area .. The bull:cow ratio is 66 per 100. Hunting here
is very limited as no roads other than the railroad traverse this ar-ea.
Hunting-by plane is also limited by the lack of, lakes and landing
strips. particularly at the higher elevations where most of the males
are concentrated during the hunting season$. Apparently hunting
pressure is not greatly affecting the male portion of this populatiol'l
at present.
Susitna and Beluga Mountains and Kahiltna Flats .. These areas
are believed to be experiencing very light hunting pressure and are
considered together. The bull:cow ratio is 86 per 100. The
young bull:adult bull.ratio is 15 per 10'0. Both ratios indicate very
limited hunting. There are no roads in either of these areas and
much of the region is inaccessible to airplanes.
Anchorage Area. The bull :cow ratio in the combined Anchorage
areas is 20 per 100. The effects of hunting are difficult to assess in
this area because much. of it is military reservation close to big game
hunting •. Apparently hunting in the areas bordering the reservations
in combination with pr.eviously mentioned mortality factors is
sufficiently effective to reduce the bull :cow ratio significantly.
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Sex and Age Composition in the
Upper Susitna and Copper River Valleys
The local areas comprising this region ~re illustrated in
Figure No. 2. In general the region includes most of the tributaries
of the Susitna River above Deadman Creek, the Nelchina basin, and
the Copper River and its tributaries from the Tazlina River 'to the
Sanford River.
The populations identified in Table No. 3 represent primarily
geographical divisions and when more· detailed studies are possible
segregation of some of t:hese areas into more local identifiable
populations seem$ possible.
The areas covered are as follows: Lake Louise, Maclaren River,
Clear Creek, Alphabet Ridge, Oshetnas and Little Nelchina Rivers,
Clarence and Black Lakes, Mt. Drurn. ~nd Upper ,Gakona River.
In Table No. 2 se"'er~l of the above a~e~s have been subdivideq.
However, for purposes of analyzing the 'population trend indicators
the combij1ed totals for each geographic area are used. The indicato:rs
of populatlon trends, productivity, survival and effects of hunting,
are again discussed iri order.
Productivity
Productivity in the Upper Susitna-Copper River basin is considered
good. The 1957 fall counts indicate an overall average of 42 calves
per 100 cows {Table No. 4); considerably better than the 1956 counts
which indicated fair productivity with an average of 27 calves per
100 cows (Table No. 8).
This area's 1957 calf:cow ratio is nearly identical to that of the
Lower Susitna Valley and Anchorage areas but productivity varies
greatly from one local area to another in contrast to the relatively
uniform productivity throughout the Lower Susitna Valley and
Anchorage areas.
The calf:cow ratios range from a high of 66 per 100 in the Lake
Louise flats to a low of 31 per 100 in the Macl~ren River area.. The
Lake Louise data are based on a sample of 84 animals and may not
be representative of the entire area. Despite the nonuniform rates
of productivity the overall calf production appears good.
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so•
-~ ------
. ~ ---.
ZIJ 16 /() S 0
St:ALI-IN MILl-S
-----
igure No. 2.
lations counted in the
& Copper River
I
t;3•
Survival
Survival as measured by the previously described survival index
is particularly variable in this area and the overall survival figure of
16 young bulls per 100 cows is excessive when compared to last
year's bull calf:cow ratio of 14 per 100 (Tal;>le No. 7). In all
probability the two figures are not comparable because the counts,
due to climatic conditions and other factors, were conducted
differently in 1957. A good example of this is the Alphabet Ridge
area on which 843 moose were counted in 1957 ·and which was not
counted in 19 56.
Another possible factor accounting for the apparent high survival
rates is disproportionate sampling of the bull population. This
probably is the case in the Alphabet Ridge and Oshetna-Nelchina
areas. The difficulties of sampling sex-segregated populations
proportionately are discussed in another section of this report.
Survival in the areas accessible to hunting reflects hunting
pressure, particularly the Maclaren and Clear Creek areas which are
traversed by the new Denali Highway. On these areas the indicated
mortality for young bulls was 21 and 57 percent, respectively. The
factors causing poor survival of young bulls in the Mt. Drum area,
where the indicated mortality was in excess of 50 percent, are not
known.
Effects of Hunting
The bull ~cow ratio for the -~ntire Upper Susitna-Copper River
area.,.is 69 per 100. This is vefy similar to the 1956 bull:cow ratio
of 67 per 100 for the same area. ·The effects of hunting are largely
;qtasked.by combining the accessible areas with those subjected to
a-lesser hunting pres sure and fo:r this reason several of the areas
representing varying degrees of hunting pressure are discussed
separate! y below.
Lake Louise. Hunting has reduced the number of bulls in this
population to 49 per 100 cows. This ratio is essentially the same as
obtained from the 1956 counts. This area: is subjected to rather
intense aerial hunting and its many lakes make much of the area
accessible. Nevertheless, aerial hunting apparently is not as
efficient as foot and vehicle hunting and the bull proportions in the
various accessible populations reflect this difference.
Maclaren River Area.
segment of this population.
Hunting is rapidly reducing the male
The bull ;cow and the young bull ;adult bull
-13-
,-
ratios for this area are 42 and 33~100 resp-ectively. In 1956 these
ratios were 62 and 31, respectively. The newly constructed Denali
Highway has opened this area to car and "swamp buggy" hunters .
. Anotherimportant factor is the terrain which is more gentle than
much of Alaska, making swamp buggy operations for moose
economically feasible from a commercial standpoint. These factors
have combined to create hu.n.ter concentrations in this area. , The
bull:cow ratio reflects the additional pressure. The creation of the
Denali ]:teserve apparently has not benefited bull moose as the sex
ratio continues to decline within the Reserve as well as outside it.
Possibly the bulls do not spend the entire year in the high country
north of the highway. The reduction of bulls in this and the Clear
Creek area is not considered undesirable from a management
viewpoint, as the Matanuska Valley herds have already demonstrated
the fact that a low bull~cow ratio does not affect the size of the annual
calf crop ... The rapid reduction of bulls does indicate that foot and
swamp buggy hunte.rs are more efficient in utilizing a game crop of
this type than are airplane hunters. In all probability any area
accessible by road will not produce trophy aD:imals after the initial
shoot.
Clear Creek. The bull removal here is similar to that in the
Maclaren River area. The bull~cow and young bull~dult bull ratios
for this area are 43 and 17~100 respectively. Here as in the
Maclaren River area the bull portion of the population is being
reduced by hunters.
Alphabet Ridge. Hunting, although intense in the accessible
portions of this area, is not significantly reducing the overall
bull:cow ratio. The bull~cow and young bull~adult bull ratios are
81 and 34~100 respectively. However, it is believed that bulls are
over-represented in this sample, distorting the bull~cow ratio. The
lakes and the ar_ea bordering the Richardson Highway are heavily
hunted by airplane and car hunters respectively, but this has not
significantly reduced the bull~cow ratios, probably beeause a major
portion of the area remains inaccessible.
;..:
Oshetna and Little Nelchina Rivers. The bull~cow and young
bull:adult bull ratios in these areas are 78 and 40 per 100 respectively.
It is believed that bulls are over-represented in this sample, distorting
the buli:cow .ratio. Nevertheless, the young bull:adult bull ratio
indicates effects of continued moderate hunting pressure. There are
several airstrips in this area and swamp buggies, also, penetrate
-as far as the Big Oshetna River.
-14-
Clarence Lake-Black River Area. The bull population of this
area is relatively untouched by hunting. The bull~cow and the
young bull:adult bull ratios are 73 and 19 per 100 respectively.
Hunting here is limited to airplane hunters and there are only a few
lakes from which t~ey .can operate. Hunting does not appear to be
influencing the number or age composition of the bull population.
Mt. Drum. The bull :cow and young bull :adult bull ratios are
73 and 11 per 100 respectively. The same ratios for 1956 are 152 .:_
and 12 per 100 respectively. In 1957 as in 1956 the lack of snow
and weather conditions limited the number of observations made in
this area. However, it is believed that this year's observations
are more representative of the existing moose populations than
those of 1956, as an attempt to sample both the timberline and
forested areas was made. This moose population is not affected
by hunting.
Upper Gakona River. This area has a bull~cow ratio of 88 per
100. Hunting, if any, is limited to airplane hunters landing on the
sandbars along the river.
Evaluation of Aerial Sex and Age Counts
Since the inception of aerial sex and age counts of the various
moose populations in 1950. efforts have been made to recognize and
evaluate the effects of the variables seemingly inherent in aerial
counts. Most of these variables have been discussed in previous
P-R progress reports. Several experimental efforts to further test
validity and to reduce certain variables in the counts were conducted
this year.
Observers
Observers are a major variable in all aerial counts. No two
individuals see and record the same animals exactly alike. In an
effort to reduce this factor one observer did all the counting this
year. The pilot also affects the total count and in some instances
the classification of the animals seen. If possible. the same pilot
should be used for all the .counts. If the data are to be-compared
from year to year. then the same combination of pilot and observer
should make the counts in order to maintain maximum continuity.
-15-
Timing of the Counts
Past exp~rience has shown that moose exhibit seasonal sex and
age habite~.t and altitudinal preferences. Frequently many large
bulls and unknown~age cows will b.e at. or above timberline during
late October, November 9 and December. A large proportion of
t~e cows with calves and many young bulls are found at lower
elevations. In counting a population so distributed, it is impossible
to know whether each stratum has been included in proportions that
will make the total sample representative of the entire population.
A total count of the area does not provide this information because
the animals below timberline are difficult to see and a large
percentage of them may be missed. The result is disproportionate
sampling.
The nxut'' or period of breeding activity extending from late
September to mid-October is the one period when the various sex
and age components of a moose population are distributed most
homogeneously. In early October several populations in the Upper
Susitna River drainage were counted in an attempt to establish sex
and age data for comparison with November counts on the same
area {Table Nos. 5 and 6). The Clear Creek drainage counts did
not vary greatly from October 9th to November 11th. The Clear
Creek drainage moose had not left the timberline river bottoms by
November 11 9 although a downstream movement was in progress.
However, the duplicat.e counts of the Maclaren River area are quite
different.
Certain segments of the Maclaren River population had moved
from the timberline areas of the Maclaren drainage to lower .
elevation.s south of the Denali Highway. The remaining animals
were mostly bulls and cows without qalves. Sex segregation was
also evident in the Clear Creek areas but as this population had not
crossed the highway it was identifiable. Also, most of this
population were at or above timberline insuring a nearly complete
count. Apparently most of the moose from these populations winter
in the browse areas south of the Denali Highway and during the
winter months the two populations are not distinguishable. The
counts made in October show that most of the animals were in groups
of 3 to Zl animals. The groups were composed of bulls {large and
smal1)9 cows and calves .. The peak of breeding had pass.ed. (see
section onReproduction) but the groups seemingly represented all
sex and agt:: components of the population. Cows with calves
frequently were not closely associated with the larger groups 9 but
were found 100 to 300 yards from them.
-16=
It is this writer's opinion that sex and age composition data
obtained during the 11 rut 11 or period of breeding activity will yield
more reliable data pertaining to population trends than will counts
made at other periods of the year. Counts made during the rut
will not always have the advantage of complete snow cover. This
will result in a smaller sample, but as indicated earlier this sample
is more representative of the true sex and age composition of the
population.
Moose Population Densities
The number of moose tallied per hour of flying was computed
for each area (Table Nos. 1 and 2).
These data could provide a valuable index to moose population
densities providing that the counts are made under similar
circumstances.
Analysis of this yearus counts show a range of 40~145 moose
per hour on the Lake Louise and Fort Richardson-Ship Creek areas
respectively. The averages for the Lower Susitna River and Upper
Susitna-Copper River Valley areas were 123 and 102 moose per
hour. The average number of moose per hour on the various areas
comprising the Lower Susitna Valley area are remarkably similar.
The Willow, Kashwitna and Matanuska Valley areas averaged 140,
139, and 141 moose per hour respectively. These averages were
computed from totals of 318, 352, and 662 moose respectively.
The areas west of the Susitna River, Susitna and Beluga Mountains,
and Kahiltna Flats, had moose-per-hour averages of 118 and 102.
The Susitna Flats area had an average of 80 moose per hour. This
area lies entirely below timberline and much of the vegetation ~s
a mature white birch~spruce association. It is possible that the.
low moose-per-hour figure reflects the difficulty of observing moose
in timbered areas rather than the moose population density of the
area. The lowland portion of Fort Richardson with an average of
88 moose per hour may also illustrate this factor.
The Upper Susitna-Copper River Valleys exhibit greater
variability in moose population densities. The range of moose-per-
hour averages for these areas are from 40 per hour on the Lake
Louise area to 130 per hour on the Alphabet Ridge area. The data
indicate that the moose population densities in the Matanuska Valley
and Lower Susitna are generally greater than those of the Upper
Susitna-Copper River Valleys.
-17-
Table No. 1. Summary of moose popUlation composition counts--Lower Susitna-Matanuska Valleys--November
and December 1957.
Young Adult Total Females iemales Females Total Total Total
Area Males Males Males W/0 W/l W/2 Females Calves Moose
Matanuska Below
Timberline 5 2 7 109 130 12 Z!H 154 412.
Matanuska Timberline 15 10 .25 118 46 5 169 56 250
Matanuska Combined 20 12 32 22.7 176 17 420 210 662.
. Willow 10 50 60 144 70 3 2.17 76 353
Kashwitna Area 12. 93 105 107 50 2 159 54 318
Susitna Flats 18 2.6 44 54 44 5 103 54 201
Mt. Susitna~Beluga 7 34 41 27 19 4 50 27 118
Kahiltna Area 9 69 78 56 26 6 88 38 2.04
· Eagle lUver 6 18 24 56 34 2 92. 38 154
l?et~rs Creek 2 2 4 27 20 1 48 2.2 74
Ft. Ric;hardson 3 6 9 32. 31 5 68 41 118
Ship Creek &c Timberline 6 20 26 72. . 37 0 109 37 172.
AnchPr.~ge Areas
Combined 17 46 63 187 12.2 8 317 138 518
Totals 93 330 423 802 507 45 1,354 597 2,374
Table No.2. Summary of moose population composition counts--Upper Susitna and Copper River Valleys
--November 1957
Youn:g-· Adult Total Females Females Females Total Total Total
Area Males Males Males W/0 W/1 W/2 Females Calves Moose
Lake Louise 5 14 19 15 24 1 39 26 84
Maclaren River 13 39 52 86 36 1 123 38 213
Clear Cr. Above Road 7 47 54 68 29 4 101 37 192
Clear Cr. Below Road 2 5 7 24 15 1 40 17 64
Total Clear Creek 9 52 61 92 44 5 141 54 256
Alphabet Ridge 79 235 314 248 130 7 385 144 843
Oshetna Rivers and
Tyone Creek 20 49 69 47 44 3 94 50 213
Little Nelchina 12 31 43 29 17 3 49 23 115
Oshetna &: Nelchina
Combined 32 80 nz 76 61 6 143 73 328
Clarence L., Black R. 20 104 124 89 78 4 171 86 381
Mt. Drum 3 28 31 27 17 0 44 17 92
Upper Gakona River 16 36 52 59 26 137~~
Kiana River 3 17 20 21 4 1 26 6 52
Totals 180 605 785 654 394 25 1, 131 470 2,386
*Counts made by Burkholder and Richards.
Table No. 3. Sex and age ratioa in Lower Susitna & Matanuska Valley moose populations--Nov. & Dec. 1957
Area
Matanuska Below
Timberline 3 250 61 7 37 1 6 2 141 412
Matanuska Above
Timberline 15 150 33 10 20 6 59 9 142 250
Matanuska Comb. 8 166 50 9 31 3 19 s 141 662
. Willow Area 28l 20 35 4 21 3 30 5 140 352
Kashwitna Area 66 ~.13 34 4 17 4 44 8 139 318
Susitna Flats 43 69 52 10 27 9 67 17 80 201
Mt. Susitna aiid
Beluga 82 21 54 21 23 5 52 14 118 118
Kahiltna Area 89 13 43 23 19 4 47 9* 102 204
Eagle River 26 33 41 6 23 4 32 7 140 164
Peters Creek 8 100 46 5 30 3 l8' 4 127 74
Ft. Richardson 13 50 60 14 35 3 15 5 88 118
Ship Cr. & Timber.24 30 34 0 22 3 32 6 2.58 172
All Anchorage
Areas 20 36 44 6 26 3 25 5 528
Combined Totals 31 28 44 8 25 4 31 7 123 2,374
:0:<13 unidentified animals--presumably cows without calves.
Table Noo 4 o Sex and age ratios in Upper Susitna and Copper River Valleys--N()vember 1957
Area
Lake Louise 49 26 66 4 31 6 38 13 40 84
Maclaren River
Above & Below
Road 42 33 31 1 18 6 68 11 106 213
Clear Creek
Above Road 53 15 37 12 19 4 38 7 192
Clear Creek
Below Road 17 40 42 6 27 3 23 5 64
Clear Cr o Total 43 17 38 10 21 4 33 6 128 256
Alphabet Ridge 81 34 37 5 17 9 97 20 130 843
Oshetna & Tyone
Creek 73 41 53 6 23 9 80 21 73 213
Lo Nelchina 88 39 47 15 20 10 104 24 77 115
Oshetna-Nelchina
Combined 78 40 51 9 22 10 88 22 74 328
Clarence Lake
Black River 73 19 50 4 23 5 47 12 127 381
Mto Drum 70 11 39 0 18 3 35 7 92 92
Upper Gakona Ro 88 44 44 19 12 123 27* 137
Kiana River 77 18 23 20 12 6 100 12 52
Totals A.bove 69 30 42 6 20 8 76 16 2,386
~cCounts made by Burkholder and Richardso
Table No.5. Comparison of Maclaren River-Clear Creek sex and age composition counts--October and . .
November 1957.
Young Adult Total Females Females Females Total Tc.tal Total
Area Males Males Males . W/0 . W/1 . W/2 Females Calves Moose
10/8/57
Clear Creek 9 33 42 63 26 4 93 34 169
Maelaren 8 33 41 20 29 1 50 31 122
Total 17 66 83 83 55 5 143 65 291
11/11/57
Clear Creek 7 47 54 68 29 4 101 . 37 192
Maclaren 2 20 22 19 6 0 25 6 52
Total 9 67 76 87 35 4 126 43 244
10/9/57
Susitna River
Jay Creek Area 5 31 36 30 11 1 42 13 91
Table No. 6. Comparison of Maclaren. River-Clear Creek sex and age composition count ratios-•October and
November 1957.
Area
10/8/57
Clear Creek
Me~.claren
Total
11/11/57
Clear Creek
Maclaren
Total
10/9/57
. Susitna-Jay
Creek Area
45
82
58
53
88
60
86
27 37 13
24 62 3
26 45 8
15 37 12
10 24 0
13 34 10
16 31 9
20 5 53 11 78 169
25 7 52 19 50 122
22 6 52 13 63 291
19 4 38 7 128 . :.192
12 4 66 9 48
18 4 41 8 86 244
14 5 77 14 52 91
Table No. 7. An index to the survival of bull calves to 18 months.
Area
Bull Calves :100
Cows 1956
Lower Susitna-Matanuska Valley
Matanuska Valley
Willow
Kashwitna
Kahiltna & Susitna &
Beluga Mountains
Su sitna Flats
All Anchorage Areas
27
14
14
22
?
?
Upper Susitna-Copper River Valley
Lake Louise
Maclaren River
Clear Creek
Alphabet Ridge
Oshetna-Nelchina
Clarence Lake-Black River
Mt. Drum
Upper Gakona River
15
14
14
?
15
?
16
?
-24-
Young Bulls :100
Cows 1957
5
6
8
12
17
5
13
11
6
20
22
12
7
?
Indicated
Percent
Survival
19
43
57
55
87
79
43
?
44
Table No. 8. Comparison of sex and age ratios in moose populations of Alaska.
-.
Young Twin Calf Young Total
Total Bulls/ Calves/ Percent Young Bull Bulls/ Moose
Bulls/ 100 Total Calves/ 100 Cows in Total Percent in 100 Bull in
Area 100 Cows Bulls 100 Cows w/Calf Herd Total Herd Calves Sample
Susitna-Matanuska Valley
1957 31 28 44 8 25 4 31 2374
1956 27 25 40 6 24 4 33 1276
1955 28 25 35 4 21 4 39 2850
19 54>:~ 63 30 2 16 601
1953 48 14 39 8 21 3 33 2700
1952 42 27 44 10 24 6 51 1421
I 1951 61 28 60 13 27 8 56 1867
N 1950 16 1140 U1
I
Mean 43 24 42 7 22 5 41 1778
Upper Susitna-Copper River Basin
1957 69 30 42 6 23 5 76 2386
1956 67 19 27 2 14 7 95 1154
1955 98 29 52 10 21 12 108._: 2500
1954 109 26 79 16 27 10 72 1700
1953 107 36 90 17 29 12 85 1100
1952 61 22 40 17 20 7 67 683
Mean 85 27 56 11 22 9 84 1587
Table No, 8, (Continued)
Young Twin Calf ":{oung 'total
Total Bulls/ Calves/ Percent Young au11 Bulls/ Moose
Bulls/ 100 Total Calves/ 100 Cows in Total Percent in 100 Bull in" > Area 100 Cows Bulls 100 Cows w/Calf Herd Total Herd Calves .Sample
Kenai**
1957 43 18 35 12. 2.0 4 45 3155
1956 51 13 2.4 10 14 4 54 3786
1955 50 14 19 10 13 4 75 3109
1954 84 14 Z7 6 1Z 6 90 2048
1953 62 12 2.6 7 14 4 39 2900
1952 50 33 21 6 12. 10 156 1136
i 1951 69 18 23 16 12. 7 108 1513
N 1950 7 1158 C7'
I
Mean 58 17 2.5 10 13 6 81 2350
Tanana Valley***
1957 60 3Z 42 2 -2.0 7 71 236*~(**
1956 84 20 47 6 20 7 71 405
1955 123 40 53 13 19 18 186 410
1954 85 35 47 5 20 13 127 109
Mean 88 32 41 7 20 1'1 114 290
* Limited sample may not be representative,
** Data from Refuge Supervisor Spencer,
*** Young bull=adult bull identification uncertain,
**** Does not include same areas as previous years,
RECOMMENDATIONS
The results of the 1957 sex and age composition counts suggest
the following recommendations.
1. Sex and age composition counts should be made during the
period of rut, in late September and early October.
2. The possibility of obtaining another measure of first-year
survival should be tested by making calf:adult counts on
certain key populations in April and early May.
Prepared by: Approved by~
Robert A. Rausch Robert F. Scott
Wildlife Management Biologist Supervisor of Game Restoration
. Date: January 31, 1958
-27-
JOB NO. 4: Distribution, Movements and Dynamics of the Railbelt
Moose Populations
PERIOD COVERED: January 3, 1956, to January 1, 1958
ABSTRACT
A study of the railroad-moose conflict in the Lower Susitna Valley
area was conducted from January 3, 1956, through May 15, 1956, and
from November 1956throughJune 15, 1957. A studyofmoose
population dynamics was conducted in conjunction with the railroad-
moose study.
The problem is created by the combination of the following factors:
( 1) an abundant moose population, (2) deep snow, and (3) large quantities
of winter moose browse along and adjacent to the right-of-way.
The critical kill area is between Houston (Mile Post 172) and
Talkeetna (Mile Post 226), a distance of 54 mi~es.
In December 1956 a system for reporting all railroad killed moose
was devised.
Two hundred twenty-five moose were reported killed in 19 55-56
and 93 in 1956-57. The reporting system is not accurate. The adjusted
total kill was 366 and 179, respectively.
Several temporary moose saving technics, suggested in 1955-56,
were evaluated in 1956-57. The following are worthy of implementation:
( 1) daylight train operation through critical areas, and (2) reduced train
speed through critical areas.
Understanding the factors influencing seasonal moose movements
is believed to be the key to formulating plans for keeping moose away
from the right-of-way.
Some moose populations inhabiting the Lower Susitna Valley exhibit
seasonal altitudinal migrations. The magnitude and extent of these
migrations are not fully understood and warrant further investigation.
Bulldozed trails and feed yards, as a means of keeping moose off
the right-of-way, were experimented with and found partially successful.
-28-
Moose guards were tested, but no definite conclusions are drawn.
Approximately 40-45, 000 pounds of moose meat were salvaged
and distributed to charitable institutions in 19 56-57. This represents .
80-90 percent of all salvable meat and an increased salvage efficiency
of 100 percent over 1955-56.
The direct cost of the moose problem to the railroad over the past
ten years is not known, but has amounted to thousands of dollars
annually.
The moose populations of the Lower Susitna Valley are probably
the most valuable herds in Alaska. Future research must be directed
towards goals which will benefit both the railroad and the moose.
The study of moose population dynamics revealed the following
information:
1. Yearling bulls { 16-18 months) are sexually mature.
2. Spermatozoa, presumably viable, are present in the
epididymis from August to December.
3. Most cows breed first at 28-30 months of age, although
a few yearling cows do breed.
4. Eighty percent of the cows in this population breed during
a 15-day period in late September and early October.
5. Fifty percent of the cows have calves by late May.
6. One hundred twenty-four sets of lungs were examined for
the presence of hydatid cysts, Echinococcus granulosus;
25, or 20 percent, were infected.
7. Ninety-eight cows were examined for pregnancy data;
87 of 93, or 94 percent, Age Class II or above were
pregnant.
B. Weights and measurements of 69 fetuses and 83 calves
and adults are presented.
-29-
9. Age determinations made on the mandibular teeth of
Z40 railroad killed moose revealed that there is a
predominance of "middle" and old age females and that
sex selective mortality factors probably affect males
excessively.
OBJECTIVES
1. To determine the patterns of distribution, seasonal movements
and population identities of moose in the Railbelt area from Turnagain
Arm to the Alaska Range, and in cooperation with the Alaska Railroad
to seek a solution to the problem of railroad-moose conflicts.
2. To obtain data on reproduction, mortality, age structure,
rate of growth and health as a basis for interpreting the dynamics of
these populations.
TECHNIQUES USED
Data on seasonal movements, distribution and population identity
were obtained by making .aerial counts of the moose inhabiting the
Railbelt area, by examining the railroad kill reports and from field
observations.
Experiments with bulldozed trails and feed yards, moose guards
and slow orders on trains were conducted in an effort to find a solution
to the railroad-moose conflict.
Examination of approximately 450 railroad killed moose provided
data on reproduction, sex and age composition, growth and health of
the Railbelt moose populations.
-30-
FINDINGS
Railroad-Moose Conflicts in the, Susitna Valley
The Problem: The Alaska Railroad traverses the winter range
of some of Alaska's most abundant moose populations, in the Lower
Susitna Valley and on portions of the Kenai Peninsulao These areas
frequently have severe winters and the ground may be. covered with
60 or m.o.re inches of snow during portions of late January, February,
and March. Moose have great difficulty traveling through this snow
and frequently enter the snow-free railroad right-of-way. obstructing
train operations, and often being killed. The number of moose killed,
which depends partially on ~he severity of the winter, has averaged
several hundred annually for the past few years. This represents an
undesirable destruction of ~ valuable resource, as well as an
additional expensive and dangerous operating hazard to the Railroad.
In January of 1956 the Alaska Railroad in cooperation with the
U. S. Fish and Wildlife Service started an investigation of the moose
versus railroad problem. This study was continued during the winter of
1956-57, as a Federal Aid in Wildlife Restoration res~arch project.
The problem, though having many facets, was studied with two.
major goals: (1) to investigate methods of removing the moose from
the right-of-,way without injuring them and without causing undue delay
to t.rain operations; and (2) to investigate methods of keeping moose off
the tracks and away from the right-of-way. A preliminary report on
the studies conducted from January through May of 1956 was submitted
in July of 1956. The present report combines pertinent data from the
preliminary report with that obtained during the winter of 1956-57.
The investigations of the railroad versus moose conflict have not
. solved the problem, but a basic understanding and definition of the
problem has been gained; the magnitude and probable effect of the kill
is known; several recommendations for alleviating the situation during
critical periods have been made and evaluated; and a study of moose
population dynamics, which may be the key to the entire problem, has
been initiated. Continued research on a limited basis promises to
unveil more answers, and is discussed in detail in this report.
History of the Problem: Moose populations in the Lower Susitna
Valley, specifically the area between Matanuska and Talkeetna, were
not considered abundant until about 15-18 years ago. Available records
and interviews with long-time valley residents suggest that moose were
-31-
scarce in the valley in the late 1920's and early 1930's. Chatelain (1951)
states that great numbers of moose first appeared in the Matanuska
Valley about 1947-48, and that large numbers of moose had wintered
along the railroad only since the early 1940's. The first records of
significant moose versus train conflicts are from 1946.
It is believed that the moose populations of the Lower Susitna
Valley, excepting the area around Wasilla, Palmer and Matanuska,
probably reached their peak about 1950:, and have slowly declined
since then. A shortage of winter browse, concurrent with several
unusually severe winters, is believed to have caused the gradual
reduction in moose numbers. Despite the great numbers of moose
present in the late 40's and early 50's, they were not sufficiently
numerous to retard ecological "plant succession", and dense stands
of birch, 20 to 30 feet high, now dominate much of the former winter
range. This winter range, which initially provided for the greatly
increased moose populations, was created by fires and clearing
operations concurrent with construction of the railroad right-of-way
and subsequent settlement activities in the late twenties.
The residual moose populations; which are considerable, now
concentrate in the remaining winter browse areas along the railroad
during the late winter months. These browse areas, created in the
last 10 to 15 years, also are the result of man's activities. The more
important areas are as follows: Willow airstrip, constructed in 1940-42;
Kashwitna River burn, 10-15 years ago; Caswell Creek, a natural river
valley; Montana Station burn, 1940-45; other burns of 10 to 15 years
ago at Mile Posts 213-215, 217-220, 222-223, Talkeetna C.A.A.
installation and airfield (exact date unknown), and a burn extending
from Mile 228 to 232 which is just beginning to produce quantities of
winter browse. These areas have been sites of major moose concen-
trations since the mid-1940 1 s, and areas of critical friction between
the railroad and moose since 1946 {Chatelain 1951). The problem first
gained widespread public attention in 1948.
The 54 mile segment between Houston and Talkeetna has
apparently been the major critical area from the start of the conflict.
An aerial count of moose within a strip one-quarter of a mile wide,
using the railroad as the center line of the strip, on January 12, 19 50,
by Scott and White of the Fish & Wildlife Service, revealed 164 moose
between Houston and Talkeetna (Table No. 1).
-32-
Table No. 1. Aerial count of moose within 1/4 mile of right-of-way,
January 12, 1950.
Section West On Tracks East Total
Houston-Willow 13 2 14 29
Willow-Ka shwitna 25 4 12 41
Kashwitna-Caswell 23 8 31
Caswell-Montana 28 2 30
Montana-Sunshine 23 1 24
Sunshine-Talkeetna 4 5 9
Total Mileage--Approximately 50 Total Count 164
In late March of 1951 Chatelain reports having counted the
remains of 104 railroad-killed moose between Houston and Talkeetna,
and the remains of 93 in the same area again in 1952. Watson
(viva .... voce) reports counting 99 railroad-killed moose on the same
area during 1953. Chatelain estimated that 75 percent of the total
kill occurred on the Houston-Talkeetna segment. In late April of 1956
the writer counted 219 different carcasses and gut piles on the same
area. In 1956, data from the reported kill and records from meat
salvaged indicated that 60 percent of the entire railroad moose kill
occurred on this 54 mile ( 11 percent of total mileage) segment of the
railroad. Again in 1957 this area accounted for 7 5 percent of the
total known kills.
It is assumed, and interviews with railroad personnel and valley
residents corroborate the assumption, that the moose kill equaled or
exceeded that of 1955-56 during years of deep snow such as 1947-48
and 1953-54, and conversely was much reduced in years of lesser
snowfall such as 1956-57. However, factors other than snowfall help
determine the magnitude of the kill (see Magnitude ofthe Kill).
The combination of deep snow, choice winter range and great
moose concentrations are the elements necessary for producing a
critical moose versus railroad problem. As indicated in the previous
discussion there are several such areas in Alaska. This situation is
unique in North America. Correspondence with wildlife administrators
in various Canadian provinces which have abundant moose populations
and associated railroads indicated that a few moose are killed annually,
but that no critical areas comparable to the Houston-Talkeetna area
exist. Reports and correspondence from Norway show that they have
a moose versus train problem of equal or greater magnitude. In an
interview with a former Norwegian railroad conductor, now living in
-33-
Anchorage, he stated that 350-500 moose were killed annually on one
segment of the railroad. He also stated that they had found no
satisfactory means for keeping the moose off of or for scaring them
from the tracks. However, he stated that no effort had been made to
do either at that time ( 1945-46) as there was a serious meat shortage
and over-population of moose, the latter brought about by curtailed
hunting during the war. It is hoped that more detailed information will
be obtained from correspondence with Norwegian game administrators.
Magnitude of the Kill: One of this project's initial objectives was
to determine, accurately, the number of moose killed annually by trains.
In December of 1955 a reporting systen: was devised (see 1956 Preliminary
Report). The investigations conducted in 1955-56 and 1956-57 show that
the present reporting system is not satisfactory, as only 60 percent of
224 known kills on the project area were reported in 1955-56, and
52 percent of 104 kills were reported from the same area this year.
Some of the reasons for the failure of the system were reported on in
19 56. One of these reasons involved freight trains, which are required
by railroad rules to come to a stop and make a train inspection after
hitting a moose or any other large obstruction. This is a safety measure.
Evidence accumulated in 19 55-56 indicated that many trains did not
observe this rule, and to avoid possible recriminations, should an
accident occur after hitting a moose, the trainmen did not report having
hit a moose. An an,a1ysis in 1956-57 of known moose kills versus
reported moose kills revealed that only about 80 percent of all train-·
killed moose were killed by passenger trains, whereas, the weekly
kill report indicated 94 percent of all kills were by passenger trains.
This further substantiates the conclusion that freight trainmen fail to
report many, of the moose hit by their trains.
It has been suggested that perhaps significant numbers of moose
run into the side of a passing train and are not observed by the train
crew. Detailed observations of over 200 moose fatalities and ofnearly
150 moose versus train encounters failed to find a single incidence of
moose running into the side of a train. It is possible that moose may
occasionally be killed in this manner, but this kill does not account
for the differences between observed and reported moose fatalities.
At present, no satisfactory method for improving the reporting
system is known. Perhaps continued solicitation for cooperation of
the trainmen will eventually stimulate an interest comparable to that
evinced by the section personnel toward moose salvage problems.
An accurate reporting system will greatly help in formulating
temporary moose-conserving measures, .suchas localized slow orders,
-34-
and would provide a measure of local population fluctuations. It is
suggested that continued effort to enlist the cooperation of trainmen in
reporting railroad killed moose be continued and, if possible, pursued
further.
Utilization of Railroad Killed Moose: Some of the problems
involved in salvaging railroad-killed moose were discussed in the 1956
Preliminary Report. Data obtained in 1955-56 show that the sections
of Willow, Caswell and Sunshine salvaged only 42 percent, or 94 of
224 railroad-killed moose (Table No. 2). This past winter's kill, as
illustrated by Table No. 2, shows that nearly 80 percent of all railroad
killed moose on these same three sections were salvaged. In 1955-56
it was determined that approximately 10 percent of the railroad-killed
moose were totally destroyed and thus not salvable. The determination
of what constitutes salvable meat varies and the writer 1 s estimates are
somewhat higher than those of the people actually salvaging the meat.
Nevertheless, only about 10 percent of the salvable kill was not utilized.
This may represent the minimum loss under the present system of
reporting and salvaging kills.
In addition to the moose not reported during the work week,
another loss is incurred by the moose killed on Saturday morning by
southbound passenger No. 7. Many of these moose are not on the
Saturday morning lineup and as no sections work on Sunday they are not
salvaged" Moose killed on Sunday could not be salvaged until Monday.
Also, heavy snowstorms make it impossible to operate gas cars and
moose killed during such storms are not salvaged.
The salvage effort and results the past season are most encouraging.
The reason for this greatly increased success is largely due to
increased interest and cooperation from the section personnel. Another
factor of unknown significance was the presence in the area of one and
occasionally two men representing the Railroad and the Fish and Wildlife
Service on moose investigations. Still another factor was the kill itself
which was not as great as that of 1955-56 and consequently the section
crews were not faced with the unpleasant task of butchering moose every
morning--not quite! Although the total kill was less, one section salvaged
nearly 80 percent more moose in 1956-57.
It is the writer 1 s opinion that this increased success in salvage
operations was due largely to the increased awareness of the overall
problem and subsequent determined effort by the section personnel.
This awareness and cooperation was stimulated by the continued interest
shown by the Alaska Railroad and the Fish and Wildlife Service. The
impact; public-relationwise, of this increased utilization of a valuable
-35-
resource should not be minimized. That 80-90 percent of all salvable
meat was utilized and distributed to charitable institutions is, in
itself, a considerable accomplishment.
Table No. 2. Moose salvaged on project area, 1955-56 and 1956-57.
Percent Total Percent
Location Salvaged Unsalvaged Salvaged Moose of Total
1956-57
Willow 19
Caswell .29
Sunshine 48
6
12
8
3
76
71
83
50
25 19.5
41 32.0
56 43.7
6
Percent of
Total Excl.
Talkeetna
20. 5
33.6
45.9
Talkeetna 3 ~--------~----------------~--------------~---------------.4. 8
Totals 77 128 100 100
79 excluding Talkeetna
1955-56
Willow 38 12 76.0 50 22.3
Caswell 30 50 37.5 80 35.7
Sunshine 27 67 30. 3 42.0 94
42.4 224 100 ----~--------------------~~----~~-----------------------Totals 95 129
Temporary Expedients
Technics for removing moose from the right-of-way without
killing them and without unnecessarily delaying train schedules fall into
the category of temporary expedients, because while they may alleviate
the problem they do not solve it. Several such experiments were tried
and reported on in 1956; three--{1) manipulation of horn and lights,
(2) slow orders, ~nd (3) daylight train operations--were studied and
tested again in 1956-57. The results of these studies are discussed in
this section.
1. Horn Blast-Light Manipulation Technic. The possibility that
many moose could be saved through proper horn-light manipulation
by the train's engineer was investigated and reported on in 1956. This
technic was further investigated during the winter of 1956-57. A total
of 150 train versus moose encounters were recorded for the past two
years. In 1955-56, 23 of 115 moose encountered were killed; 7 of 40
were killed in 1956-57. However, the variables of moose abundance,
-36-
snow depths, and personalities are such that direct comparison of the
results is not possible. The only conclusive result seems to be that
sounding the train's horn at a distance greater than 100 yards from a
moose is unwise; although the sound of the horn initially frightens the
moose into leaving the tracks, prolonged or early sounding confuses
or angers the moose and it frequently reenters the tracks before the
engine has passed. Dimming or turning off the headlights has no
apparent effect on the behavioral response of the moose. Most engineers
sincerely attempt to avoid hitting moose, and many have developed
technics for avoiding and scaring moose encountered on the tracks.
However, the value of present moose scaring technics is questionable.
2. Speed. Train speed is an important factor in determining the
fate of moose encountered on the tracks. .Comparison of a number of
train versus moose encounters at speeds greater and less than 30 miles
per hour reveal that, other factors being equal, the train traveling
30 miles per hour or less kills fewer moose.. This fact has definite
moose saving possibilities, since critical areas along the right-of-way
can be determined in advance by making aerial counts of moose
populations along the railbelt (Figures 1 and 2). Also, the data obtained
in 19 55-56 demonstrated that the areas along the. right-of-way having
the combination of good winter moose browse, deep snow and great
moose concentrations also have the greatest annual railroad moose
kill.
If a slow order is placed on night train operations through these
areas, considerably fewer moose will be killed. One such area was
detected this past winter; the area between Mile Posts 198 and 224.
On February 7, 1957, a slow order was placed on Train No. 8, night
passenger to Fairbanks. The writer recorded 17 moose versus train
encounters while riding in the cab of the slow-ordered train; no moose
were killed. Prior to the slow order as many as 10 moose had been
killed in one night.
The greatest concentrations of moose appear along the right-of-way
at different periods throughout the winter months (Table No. 4).
Normally the moose do not remain in one locality long, and the affected
areas are not extensive; thus it is seldom that an area greater than
15-30 miles would need to be slow-ordered. This should not cause
excessive delay to train schedules and, in fact, should significantly
reduce delays caused by moose fatalities.
Slow orders, like other temporary expedients, will not solve
the problem, but will reduce the number of moose fatalities and possible
train damage and delay resulting from moose-train encounters.
-37-
I
I..V
():)
I
Figure No. 1. Number of moose counted within 1/8 mile of tracks on 19 periodic aerial
counts; winter 1956-57.
10Qmoose
-
7 5
Q .... -5
2 5
,.... ,....
r-
...-. nn ..
October November December January Febr.uary .·March April
Figure No. 2. Number of moose counted within 1/8 mile of tracks on 6 periodic aerial
counts; winter 1955-56.
1.0 moose 10
'5 7
5 . .Q
2 .~ r-
' October November December January February March April
3. Day versus Night Train Operations. Data obtained from aerial
counts of the railbelt moose populations, observations from the cab of
train engines, ground reconnaissance work and numerous interviews
with train crews indicate that relatively few moose are encountered on
the tracks during the daytime. Aerial counts made on 1, 840 moose
during the past two winters reveal that approximately 70 percent of
them were bedded down during the day. It is generally believed that
moose are most active in the early morning and evening, and that they
usually are bedded down during the middle of the day. The data obtained
during the present study further supports this belief.
In an. attempt to determine which trains ace ounted for the most
moose, section crews were requested to keep a record showing the
time of day and train involved in each moose fatality. This information
showed that approximately 80 percent of this year's total kill occurred
at night or in the early morning, i.e., prior to 0600.· This information
also indicated that the night passenger trains to and from Fairbanks
accounted for nearly 8.0 percent of the moose fatalities. These were
the only regularly scheduled night h;ain operations.
Due to traffic schedule changes a-majority of the trains operated
through the Houston-Talkeetna area,during daylight hours in the winter
of 1956-57, yet these trains accounted for only 20 percent of the total
number of moose fatalities.
Train operations through critical kill areas should be scheduled
for daylight hours whenever it is economically feasible.
Keeping Moose Away from the Tracks
A successful means for ending the moose versus train conflicts
in the Lower Susitna Valley will be obtained only by removing or
diverting the moose populations from the right-of-way. This is one of
the few abundant :moose populations in Alaska that is readily accessible
to hunters and vacationists, either by car or train, and since it is also
located near Alaska's largest city, Anchorage, the herd is of tremendous
economic and aesthetic value. A major reduction in numbers of moose
is not considered a logical or satisfactory solution to the problem.
It is recognized that before a permanent program can be formulated
for keeping moose away from the right-of-way the seasonal movements
of the moose populations involved must be more fully understood. Moose
are known to exhibit definite seasonal migrations in parts of British
Columbia and Norway. The seasonal influx of moose into choice winter
browse areas along the railroad is believed to represent this type of
movement; however, the distances and magnitude of these movements
are not yet known.
-39-
Movements. The Alaska Railroad from Houston to Talkeetna
roughly parallels the Susitna River, ranging from several miles east
of, and to the river's edge. Numerous tributary streams of the Susitna
River eros s the railroad and form excellent avenues of approach,
complete with choice winter browse, for the moose. The headwaters
of these streams are in the Talkeetna Mountains some 10~30 miles
east of th.e railroad. The foothills and timberline areas of these
mountains comprise the ,fall and early winter range of great numbers
of moose. Aerial sex and age composition counts made in October
have counted several thousand moose near or above timberline from
the headwaters of Montana Creek to the Little Susitna River. These
counts are not designed to indicate total population but merely to
provide sex and age composition data. Most of the moose are still in
small bands or "harems" when October counts are made. In November,
these groups disband and some of the moose apparently begin the
annual movement to the wintering areas adjacent to the right-of-way.
Aerial counts and the railroad kill (Figure Nos. 1, 2, and 3) indicate
that the first incidence of increased moose activity along the tracks
begins in November ... The timing and magnitude of this first movement
may be influenced by snowfall as well as social and behavioral factors.
In. 1956, ,.early snowfall in the timberline areas apparently caused an
early migration into the lowland areas. This was reflected by the
hunter _kill during the-November moose season when at least 200 male
moose were killed in the valley areas, at least 20 of which were killed
in the immediate vicinity of Willow airstrip. In contrast, the hunter
kill inNovember of 1956 was less than 100 animals and no moose were
killed around Willow airstrip.
The aerial counts and railroad kill of the past two years reveal
striking similarities in population densities and corresponding increases
or decreases in moose fatalities (Figure Nos. 1, 2, and 3). Moose
populations and fatalities reached their peak in February of both years,
with nearly 50 percent of the total kill occurring in this month
(Figure No. 3). This corresponds, also, with the time of deepest
snow cover (Table No. 3}. Snow depths definitely influence the
magnitude and in some instances the date of greatest moose kilL
However, the close correlation between the peak of moose population
densities and subsequent dispersal for the past two years, years of
great contrast in snow depths, suggest that the population movements
may represent basic seasonal movements--movements influenced
but not caused by the depth of snow cover (Figure Nos. 1 and 2).
-40-
I
~ .....
I
Figure No. 3. Percent of total railroad killed moose, by month, 1955-56 & 1956-57.
ercent
October November December January
0 1956
IJJIIO 1957
February March April
Table No. 3. Snow depths winter 1956-57.
Area Date Average Range
Willow--M. P. 186 12/17/56 17" 9-26
II 12/28/56 19" 12-27
II 1/18/57 30'' 15-44
II 3/5/57 33 11 27-45
Caswell--M.P. 202 12/26/56 27 11 24-27
II 1/16/57 39 11 36-43
II 1/23/57 37" 34-39
II 4/3/57 39'1
Sunshine--M.P. 216 12/20/56 24" 18-33
II 1/17/57 34 11 20-45
rr 2/15/57 43" 36-52
11 2/27/57 39" 33-46
II 3/1 I 51 44" 35-52
II 4/2/57 38" 33-46
Measurements were taken from five representative terrain types at
each location.
Examination of the kill by area shows that the area first
evidencing increased winter moose populations is Willow, where the
kill may begin in October {Figure No. 4). This area has sustained
great kills in the past years, including 1955-56; however, the kill in
1956-57 was relatively light. Interpretation of moose movements on
this area is complicated by the fact that aerial counts indicate very
few moose wintering adjacent to the tracks {Table No. 4). Winter
browse is very limited along this portion of the track, and that
available is adjacent to the right-of-way. It is possible that the
-relatively great kill on this section reflects a browse shortage rather
than an abundant moose population.
The greatest percentage of the kill on this section occurs prior
to February, whereas the peak of moose abundance and moose fatalities
occur in February on the Caswell and Sunshine areas. Aerial
observations, combined with several fortuitous snowfalls, enabled the
investigator to trace the progress of a major movement of moose into
the above areas. Aerial counts made in late January revealed great
numbers of moose tracks and moose along the tributary streams of the
Susitna, principally the Talkeetna River, Kashwitna River, Montana
Creek, Goose Creek, Sheep Creek, and Caswell Creek. Presumably
the moose were headed toward the winter browse areas along the
Susitna River and the Alaska Railroad. At the time of this movement the
-42-
· ....
100
75
50
25
100
75
50
25
Figure No. 4
1955-56 & 1956-57 Railroad Moose Kill
Percent of Kill, qy Sections, for ~ch Month
Willow Area-~M.P. 160-192
October November December January February March
ercent Caswell Section--M.P. 192-208
'0 "CC
Q) Q) .p .p s F-1
0 p., p.,
Q) Q)
~ ~
Q) Q) ~ s:: s::
s£ 0 ~ :z;
October November December January February March
ercent Sunshine Area--MoPo 208-230
"0 i Q) .p .p
f..t s 0 p., p.,
Q) ~ ll::
Q) ~· Q) Q) s:: s::: s:::
0 ~ 0 ~ :z; 12:'<
October November December January February March
rnrn 1955-56
c=I 1956-:-57 -43-
Table No. :4. Aerial counts of rail belt moose populations
Date
10/21/56 2 2 4
11/8/56 9 6 2 1 7 6 8 '39
11/23/56 11 2 4 1 18
12/3/56 19 . 37 3 3 2 14 5 4 5 92
12/11/56 17 39 2 3 1 1 2 1 11 77
12/17/56 19 41 3 2 1 4 6 76
12/29/56 4 7 15 1 2 5 11 2 12 59
1/7/57 14 32 9 1 8 5 3 20 92
1/16/57 2 49 16 7 13 1 14 ' 102
1/21/57 12 .6 6 13 .37
1/31/57 19 . 36 6 14 16 4 8 103
2/5/57 13 47 4 1 11 . 12 11 16 115
2/11/57 14 31 2 .2 .2 12 9 5 17 94
2/20/57 13 75 8 5 5 8 3 13 130
3/5/57 16 16 1 10 3 8 54
3/19/57 13 12 .2 1 5 3 4 40
3/25/57 8 9 . '3 9 5 10 11 .55
4/1/57 6 2 1 3 2 4 18
4/12/57 1 1 2 4
Totals 171 446 89 13 9 25 107 115 62 172 1,209 63.6
Percent
of Total 14. 1 36.9 7.4 L1 . 7 2. 1 8.9 9.5 5. 1 14 .• 2
Percent of Kill 2.5 5.8 4.9 4 .. 1 4. 1 7,4 12, 3 18. 1 12,3 28.0
All moose within 1/8 mile either side of track are counted.
snow was not deep enough in the foothills or at timberline to seriously
hamper moose foraging activities. A possible important factor was the
freezing over of the upper reaches of the streams and rivers; thus
affording the moose an easy avenue of travel. The moose reached the
tracks on or about the first week of February, and this was immediately
reflected in the increased railroad kills (Figure No. 3), moose counted
(Table No. 4), and general moose sign. The snow accumulations were
not great enough to seriously hamper moose movements and the majority
of the moose moved across the tracks to winter browse areas along the
Susitna River or settled in the browse a~eas adjacent to the right-of-way.
The number of moose killed by trains declined sharply concurrent with
the moose dispersal.
During years of great snow accumulations, such as 1955-56, it is
believed that a greater portion of the moose would have remained along
the railroad with its combination of avallable browse and easy walking.
Winter Browse Areas. Localization of moose populations along
the railbelt area is believed to be a possible solution to the current
problem. ;;
In an attempt to evaluate the effectiveness of winter browse areas
as moose localization agents, a large (approximately 10 square miles),
recently burned over area which contains large quantities of favored
winter moose browse was selected for study. This area, located
. about 10 miles northeast of Willow, was known to have over-wintered
a large number of moose in 1955-56. Periodic aerial counts of moose
utilizing this area were made from mid-October, 1956, through
mid-April, 1957 (Table No. 5). Although several distinct population
fluctuations were noted, at least several hundred moose are known to
have over-wintered on this area, without approaching the railroad.
Several other browse areas were periodically counted during the
past winter (Table No. 6). Information obtained from these observations
indicate that strategically located winter browse areas could attract
many of the problem moose; however, until the nature of the fall and
winter migrations are more fully understood, no detailed recommenda-
tions for creating such areas can be made.
-45-
Table No. 5. Compilation of aerial counts of moose inhabiting the
Willow Burn.
Total Calf: Counting Moose
Area Date Moose Adult Calf Adult Conditions Per Hr; ·
Willow 10/21/56 122 95 27 28:10.0
Burn 11/8/56 125 95 30 32:100 Poor 300
II 11/23/56 101 71 30 42:100 Very Poor 224
It 11/23/56 46 34 12 35:100
" 12/3/56 199 137 62 45:100 Very Good 398
II 12/17/56 191 144 51 '35 :100 Good 370
II 12/29/56 119 90 29 32:100 F·airly Good 238
II 1/7/57 107 81 26 32:100 Fairly Good 214
II 1/16/57 166 123 43 35:100 Good 200
II 1/21/57 114 87 27 31 :100 Good 201
II 2/5/57 122 108 14 13:100 Good 236
" 2/11/57 130 101 29 28:100 Fair 243
II 2/20/57 88 77 11 14:100 220
II 3/5/57 76 59 17 28:100 Poor 127
II 3/19/57 63 50 13 26:100 Very Good 151
II 3/19/57 43 30 13 43:100 Very Good 103
II 3/28/57 111 90 21 23:100 Good 175
It 3/28/57 100 82 18 22:100 Good 187
It 4/1/57 23 18 5 28:100 Poor 160
II 4/12/57 15 12 4 27:100 Fair 48
-46-
Table No. 6. Compilation of aerial moose counts on other areas.
Total Calf: Counting Moose
Area Date Moose Adult Cal£ Adult Conditions ·Per Hr.
Montana 12/29/56 9
Burn 2/5/57 33
II 2/11/57 21
II 3/5/57 17 14 3 21-:100 168
II 3/25/57 33 396
II 4/I/57 44
" 4/12/57 1 1 6
Sunshine 11/8/56 36 25 11 44:100
Burn 1/16/57 13 11 2 18:100
It 2/20/57 18 15 3 20:100 135
It 3/5/57 22 19 3 16:100 165
It 3/19/57 15 12 3 25:100 Very Good 180
II 4/12/57 10 8 2 20:100 Good 60
Wasilla 12/17/56 123
Burn 12/29/56 38 25 13 52:100 Fair
n 1/7/57 30 22 8 36:100 Fairly Good 180
" 1/16/57 43 26 17 65:100 Very Good 258
II 2/5/57 15 10 5 50:100 150
II 1/31/57 13 10 3 30:100 156
II 2/20/57 34 26 8 31:100 140
n 3/5/57 18 15 3 20:100 135
II 3/19/57 . 2 2 0 0:100 Very Good 24 .
II 4/12/57 0 0 0 Poor 0
-47-
Bulldozing. Experiments. Creating trails parallel to the right-of-
way in an effort to divert the moose from the tracks was tested by
bulldozing trails in the Houston-Willow and Montana areas in January
of 1956. The results of this experiment indicated that bulldozed trails
might be an efficient temporary expedient for keeping moose off the
tracks.
In addition to walking along the trails the moose utilized the browse
created by the trail clearing operations. However, numerous moose
persisted in leaving the trails and crossing the tra,cks, often wa:q_4ering
up and down them, feeding on the browse available and obstructing
train traffic. The possibility that a combined trail, feed yard and ·
nmoose guard" operation might localize certain moose populations
was proposed and investigated this past winter.
The feed yards were created by bulldozing. down. quantities of
aspen, birch and willow trees in conjunction with the trail-making
operations. The moose guards are adaptations of cattle guards,
placed on the railroad tracks at points where the bulldozed trails cross
them to prevent the moose from entering the right-of-way.
The area selected for this combination experiment was the
critical kill area at Montana, Mile Posts 207-212. This six-mile area
accounted for 25 percent of last year's total known kill, and also
borders one of the few remaining areas of high quality winter range.
Originally, the plan was to be effected in November, but an e.quipment
shortage delayed inauguration until February. Fortunately, the moose
populations by-passed this area in early winter and located along the
Susitna River and near Sunshine. In February, when construction of
the project was completed, the moo.se population present was so low that
little quantitative da.ta was obtained; however, in March between 40-50
moose moved into the immediate a;rea, using the trails, feed yards and
frequently crossing the right-of-way. These moose seemed perfectly
content to eat the browse provided them by the feed yards and to wander
about on the trails, occasionally making short journeys to choice browse
areas, but almost invariably returning to the trails. Snow conditions
during this period were not critical to moose movements and the use of
the trails would doubtless have been greater had the snow been deeper.
The moose guards proved only partially effective. Initially a
snow berm was placed between the trail and edge of the guard to prevent
moose from circumventing the guard. However, by March this had been
destroyed by snow removal operations and frequently the guard was
clogged with snow. A few moose did cross the guard or walk around
it, but they generally wandered up or down the tracks a few hundred
-48-
yards and then returned to ,the trails. Several instances of moose,
frightened by trains or gas cars, crossing the moose guard were
recorded, but no instances of moose voluntarily crossing the guard
when it was functional were recorded.
Only two moose were killed on this area during the period of
great moose abundance. This total cannot be compared directly tb the
1955-56 total, because snow depth.s an,d moose abundance were not
the same. However, this area did have a greater moose population,
snow as deep or deeper, and fewer moo~.e fatalities than similar areas
north of Sunshine.
The data obtained from these experiments indicate that certain
moose populations can be effectively .localized and kept off the tracks
by creating alternate trails and feed yards for them. The proposed
routes for the trails should be marked and initially const:ructed in
November prior to deep accumulations of snow. This will· alleviate
possible damage to equipment and reduce the time required for clearing
the trails in mid-winter. In all probability the trails will have to be
cleare,d l:mt once, because the moose will keep them open once they
have fo!lnd them. The feed yards could also be made in November.
The moose guards, which need more testing, should be kept free
of snow at all times, and the snow berm protecting the end of the guards
should b.e maintained. The aerial counts and ground reconnaissance
studies have identified the major winter ranges adjacent tb the right-
of-way. In all probability these areas, listed in the 1955-56 report,
will continue to be associated with the majority of the moose-train
conflicts in the Lower Susitna River valley.
It is recommended that moose trail, feed yard and guard experiments
be further tested in 1957-58, preferably by selecting one general area
such as the Montana-Sunshine section; bulldoze the trails and feed yards
in November or early December; make equipment available on a priority
basis; investigate the pas sibilities of using the land clearing "ball and
.chain de:Vice" for creating feed yards.
The Kill. Analysis of the sex and age composition of the sample of
moose obtained from the railroad kill provides much valuable biological
information pertinent to proper management of this important moose
herd. The data obtained on the sex and age composition of the railroad
kill of the past two years is illustrated in Table No.16. The sample from
1955-56 is believed to constitute a representative cross section of the
moose populations present along the railbelt, and it corresponds closely
to the aerial sex and age composition counts made in November of the
-49-
same year. However, the 1956-57 kill seems to have been selective
for calves, indicating a calf:cow ratio of 68:100, whereas the aerial
counts indicated a calf :cow ratio of 27:100.
Observations of moose confronted by an oncoming train suggests
that during years of shallow snow cover trains may be selective for
calves. Moose calves remain with the female until they are at least
one year old, following her at all times, especially during the winter.
months when snow hampers the calf's movements more readily than it
does the adults. It is this behavioral trait that accounts for a
disproportionate kill of moose calves. Frequently the female leaves
the right-of-way only several yards in front of the oncoming train; the
calf trailing her does not make it, and is killed. When the snow is
deep, such as 1955-56, neither moose leaves and both are killed.
Also, if the c.ow is killed and the calf is not, the calf fails to make
the necessary adjustments in fending for itself and almost invariably
is killed within a few days.
·.In general, the railroad kill is believed to sample proportionately
the winter moose populations inhabiting the railbelt area, though calves
may be disproportionately represented under certain conditions.
Economic and Other Aspects of the Problem
The problem of evaluating the economics of the moose versus
railroad conflict involves many considerations, including certain
aesthetic values on which the dollar sign of economics is difficult to
place. Among the more important values which must be considered,
two seem outstanding: ( 1) the direct costs to the railroad; and
(2) the importance of the wildlife resource involved.
1. Direct Costs. The cost to the railroad for salvaging a moose
is approximat.ely twenty-five dollars. This cost has averaged several
tho':lsands of dollars annually for the past decade. In certain years,
additional funds were expended for removing unsalvaged moose
carcasses from the right-of-way in the spring. Trains are occasionally
derailed by moose, and this, perhaps, is the most expensive type of
damage caused by moose. Several such accidents are reported to have
cost many thousands of dollars. In February of 1956 a moose caused
the derailment of a loaded flatcar at Montana Station, Mile Post 209.
Mr. Whalen, Chief Clerk of Engineering, the Alaska Railroad, has
estimated the damage to equipment and freight at three thousand dollars.
In addition, considerable expense was incurred for labor expended on
repairing track, switch and rolling stock, and for delayed train schedules.
-50-
In mid-winter, when moose populations are abundant along and
on the right-of-way, trains are frequently delayed several hours by
moose encounters and subsequent accidents. This, also, costs money
as well as inconvenience to passengers who have business appointments
or plane connections to meet.
_The combined total cost of these various expenses and inconveniences
are not known, although they are co:n&ider.:a:ble. In 1955-56 the total
cost of salvage operations and equipment damage was calculated to be
ten thousand dollars. The costs of labor, delays and inconvenience
for the same period are not known, hut. ar.:e believed to exceed the cost
of salvage operations and equipment damage. These opet'ational
expenses are cumulative and continuing, and should be considered when
planning future winter railroad operations, as well as future research
projects.
The determination of a cash value for game· meat is an arbitrary
matte.r; however, cold storage plant operators in Anchorage who have
had considerable experience dealing with meat values, agree that a
value of 25 cents per pound of .railroad salvaged meat is not excessive.
In 1955-56 the cost to the railroad for salvaging approximately 63,000
pounds of moose meat was 4, 266 dollars; a cost to the railroad -of
about seven cents per pound. Thus, the. intrinsic value of the meat is
three times greater than the cost of salvaging it. This substantiates
the belief that salvage operations are justified economically, as well
as being a moral responsibility.
• 2. Importance of the Wildlife Resource Involved. This problem,
unique in North America, apparently had little significance at its
inception, and at that time the moose population was very abundant.
However, the human populations of the Lower Susitna Valley have
increased many-fold since 1946, and land use policies have been
affected accordingly. The result is an inverse ratio; as human
populations and land clearing operations increase, available winter
moose range decreases. Concurrent with the decreasing moose
population have been increased recreational demands. upon it. This
trend will result in greatly increased moose values, real and aesthetic.
The current flurry of land withdrawals, particularly of choice winter
range along the right-of-way, which have easy access, and are also
more economical to clear, illustrates the foregoing discussion of
future moose population trends.
At present, available winter range during severe winters such as
1955-56 is believed to be a limiting factor on moose numbers between
Houston and Talkeetna. As discussed above, this range is shrinking
-51-
due to human encroachment and to normal plant succession. This
combination of limiting factors dictates a reduced moose population
in the affected areas. However, the remaining moose population
will co.ntinue to concentrate on the favorable winter ranges along the
right-of-way. Should the progression of events occur as outlined,
then the annual kill by the railroad could significantly reduce the
number of moose available to the hunter, and under certain conditions
of severe winters actually become the major limiting factor to the
moose population.
Public relations is another important factor to be considered.
The public, a,s has been amply demonstrated in the past years, reacts
quite violently to any seeming disregard for our wildlife resources.
This factor must also be given ample consideration in future moose
policy formulation .
. The only foreseeable alteration of the events outlined in the
previous discussion would be an.-qninterrupted series of mild winters;
creation of more winter range through catastrophe, i.e. , fire or wind,
or through artificial means such as the use of herbicides, cutting or
bulldozing.
The problem of moose shortages is certainly not present today,
except locally, but the need for careful formulation of future policy
toward winter railroad operations and proper management of wildlife
resources makes it imperative that the growing problems be recognized
now. As a result, future work on this problem should be directed
toward projects which will result in benefits to both the railroad and
the moose population.
-52-
Reproduction
Quantitative data illustrating the age of sexual maturity, period
of rut, and fertility rates for the moose of North America, and
particularly for the Alaskan subspecies, are extremely limited or
totally lacking. The data presented in this report represent some of
the results obtained from examining moose killed accidentally,
illegally, or by hunters, and from aerial·and ground observations
made of the moose populations inhabiting the Matanuska Valley and
Railbelt areas. These data were collected between January 5, 1956,
and January 9, 1958.
Age of Sexual Maturity: Most workers have not considered
yearling ( 16-19 months) males important contributors to the reproductive
segment of moose populations. Skuncke ( 1949) indicates that in Sweden
male moose may be capable of fertilizing cows when two and one-fourth
years old, but that the larger bulls seldom allow them the opportunity.
Peterson (1955} mentions that the age of sexual maturity in moose is
not definitely known, but that some authorities believe bulls are capable
of breeding at 16 months although they seldom have the opportunity to
do so.
In the Matanuska Valley, hunting has significantly reduced the
male segment of the population, and has altered the age composition
of the remaining males to approximately 90 percent yearlings above
Age Class Calf. Here it is believed that yearling males are an
important factor in the continued high fertility rate among the female
moose in this area (see Fertility Rate}.
Observations of moose rutting behavior by this writer have been
limited to, largely, the period immediately pre-and post-rut periods
when the "harem-like" groups consist of both adult and yearling males
seemingly intermingled with the accompanying cows and calves,
apparently without conflict. However, several instances of moose
jousting or pushing one another were observed.
In the Matanuska Valley groups of 10-30 animals consisting of
cows, calves, and 1-4 young bulls were observed in late October and
one instance of what appeared to be successful mating by a yearling
bull with an adult cow was observed on October 29, 1957.
Aerial sex and age composition counts of the Matanuska Valley
indicate a bull :cow ratio of 10:100. Thus, since 90 percent of the
bulls are yearlings, the older bulls would be required to service
100 cows each; if one assumes that yearli;n.gs are not capable of
fertilizing cows.
-53-
Further confirmation that yearling male moose are capable of
fertilizing cows is provided by Buckley (viva voce), who reports that
examination of the epididymis contents of three yearling male moose
collected near Fairbanks on September 7, 12, and 17, 19 53,
respectively, revealed that spermatozoa, presumably viable, were
present in each instance. Microscopic examination of the epididymis
contents of 17 yearling moose killed in August, September, and
November, 1957, in the Matanuska Valley yielded similar findings
(Table No.7 ).
Table No.7 . Breeding condition of bull moose as indicated by the
presence of spermatozoa in the epididymis.
Collection Spermatozoa
Date Present Age Accession No.
8/22/57 Yes I 892
8/22/57 Yes I 636
8/22/57 Yes I 897
8/22/57 Yes I 895
8/24/57 Yes I 615
8/25/57 Yes I 558
8/25/57 Yes I 832
9/1/57 Yes I 532
9 I 2/57 Yes I 519
9/2/57 Yes I 917
9/8/57 Yes I 923
9/8/57 Yes I 822
9/15/57 Yes I 668
9/18/57 Yes I 588
11/2/57 Yes ? 793
11/3/57 Yes I 800
11/23/57 Yes I 778
12/8/57 Yes (4-5 ?)
1/8/58 Yes~· VIII 965
3/31 I 57 Yes* I 444
12/20/-56 ? ** Calf
* Very few spermatozoa_.-rio spermatozoa w/tails observed.
** A very few developing spermatozoa in testis and what appeared to
be decomposing spermatozoa in the epididymis.
Yearling male moose are capable of and do fertilize cow moose,
and may become an important factor in the reproduction of a heavily
hunted moose population, such as that of the Matanuska Valley.
-54~
Information regarding the age at which female moose first breed
is seemingly as speculative as is the same information on male moose.
Peterson {1955), citing Lonnberg (1923) and Skuricke (1949),
postulates that a few females probably breed at 16-18 months, but that
most breed at 28-30 months. Skuncke states that yearling females
occasionally conceive and that most females breed first as two-year-olds,
but that frequently they do not breed until they are three. Ritcey and
Edwards (personal communication) found no pregnant yearlings in a
sample of 15 uteri collected from yearlings during the period when
moose normally ·are pregnant. They furthe.r express the belief that no
females of this population (Wells Gray Park, B. C.) breed prior to
their third falL
During this study the uteri and ovaries of 31 moose, Age Class
Calf to Class III, were examined. Examination of the uteri and ovaries
of seven calves revealed no instance of ovulation or pregnancy. The
uteri or ovaries of nine yearlings have been examined. Six of the
yearlings were ,colle;cted during the winter months and three during the
late fall. One, a very large yearling, collected in Spenard,. Alaska,
on March 19, 1957, was pregnant. The ovaries of a yearling collected
on November 10, 1957, showed a corpus 1uteum, partially lutenized;
no fetus was found. The corpus luteum may have represented an
ovulation which did not re'sult in pregnancy, or it is possible that the
embryo had not attached to the uterine wall and was lost during
examination. No indications of ovulation or pregnancy were observed
in five other yearlings examined. Examination of uteri and/ or ovaries
from 17 Age Class II and III individuals collected between November
and May showed that· only two were not pregnant. Ovarian analysis in
this age. group revealed an average of 1. 4 corpora albicantia of
corpora lutea of pregnancy per pair of ovaries (Table No.8 ). This
suggests that both two and three year old moose are represented in
this sample.
These data indicate that no calves of the year breed or ovulate;
that a few yearling females do breed, although the data is too limited
to be significant; and that 88 percent of two and three year old females
were pregnant, indicating that most female moose on this range breed
first at 28-30 months.
Period of Rut: The period of rut or breeding of moose, similar
to many other facets of its reproductive cycle, is known only in a
general sense.
Most authorities agree that rut activities commence in early
September and continue through most of October. However, exact
-55-
Table No. 8. Corpora albicantia incidence in moose ovaries.
I 6 2 0 0 0 14 0-0 0 0
I
U1 II & III 5 1 7 0 7 11 0-2 1.4 .64 0'
I
IV & V 6 2 20 5 25 14 0-5 3.3 1. 78
VI & VII 8 53 53 16 0-7 6.6 3.3
VIII & IX 6 58 58 12 2-7 9.6 4.8
Totals 31 5 138 5 143 67 0-7 4.4 2. 1
dates and true peak of ovulation and conception are not known. Ritcey
and Edwards {personal communication) state that most cows in Wells
Gray Park, British Columbia, breed during a ten-day period in late
September, and that three periods .of oestrous occur from early
September through October. Skuncke (1949) reports that moose in
Sweden breed during the first two weeks of October. Specimens or
observations of four phases of the reproductive cycle of the moose
populations inhabiting the Matanuska Valley and Railbelt areas were
collected in an attempt to more accurately delineate the period of
sexual activity. The data obtained includethe following:
A. Collection of moose testes.
B. Periodic aerial counts of moose inhabiting known calving
areas during late May and early June.
C. Collection of moose embryos and fetuses.
D. Coll.eetiorr of moose ovaries.
A. Testes Collected. Testes of certain cervids reflect the
period of sexual activity through increased size and weight. Cheatum
( 1956) reported that volumetric determinations of white-tailed deer
testes indicated a fall peak in size. He presented data which shows
that the peak of testes size, which occurs in November in that area,
coincides with the peak of conception.
One hundred and sixty-seven pairs of moose testes were collected
during the winter of 1956-57 and the fall and winter of 1957-58. The
testes were preserved in W percent formaldehyde. Standardization
of the portions of the testes used for weight and volumetric determina-
tions was obtained by dissecting the testes free from the tunica
vaginalis, and by severing the vas efferentia from the testes. This
!process removed all extra tissue from the testes, particularly fat
deposits, which were considerable on testes collected in August and
September. The testes were then weighed to the nearest gram and
volumetric measurements, using the water displacement technic, were
taken to the nearest cubic centimeter. In this report only the weight
measurements are used.
Male moose vary greatly in body size, both with respect ;to age
and individual variation. It is believed that body size and testis size
are proportional. The greatest proportional difference between both
body and testis size is between Class I bulls and older age class bulls.
Because of the great proportional difference the two age categories
are considered separately. If a larger sample of testes from known
age animals were available, division according to age classes might
reduce the great range in testis weights and give some indication as
-57-
to which age group first reaches a peak of breeding condition, if such
a difference exists. "'
The weights of the testes from yearlings clearly indicate a weight
increase from August 20 to September 20, but a definite decrease in
weight is not apparent until December and succeeding months. The
sample of testes from November, however, is small and in view of
the great size variations within this age class it is possible that this
sample is not representative.
The curve, established from the weights of 87 testes collected
from moose older than Class I and averaged by periods, is illustrated
in Figure No. 5. Again the range in weight is great (Table No. 9).
The points for the generalized curve were obtained by averaging the
testis weights by 5 and 10 day periods from August 20 to September 20
and from November 1 to 30. Testes collected later were averaged
by two week periods, These data indicate a definite weight increase
from August 20 through September 20 and a corresponding decrease
through November and December with a possibly constant weight from
January through. March.
If the curve in Figure No. 5 accurately portrays moose testis
development, the peak of male breeding condition occurs about
October 1. Unfortunately this coincides with a closed hunting season
and no testis weights are available for this period.
Table No.9. The average and range in weight,o£·87 testes from adult
moose.
Date ·No. Testes
August 20-25 27
August 30-Sept. 7 8
September 8-14 9
September 15-20 11
November 1-6 1
November 7-13 3
November 14-20 4
December 8 2
December 18 2
January 1;..4 4
January 8-31 6
~ebruary 1-14 10
Total 87
Ave. Weight
(grams)
7 6. 0
79.4
86.3
90.0
69.0
58.3
57.2
44.5
40.0
32.7
42.3
35.4
-58-
Range
52-92
59-109
63-110
68-120
69-69
56-62
46-66
42-47
35-45
32-34
34-56
28-43
100 (grq.ms) , ,
0
70
!
~ 60
I
50
40
30
July
/
Figure No. 5.
I
/
/
I
The average weights of 87 adult moose testes.
,.-,
/ \
/ \
\
' \
' \
'
August September October November December January February ~arch
B. Parturition. Aerial counts of moose inhabiting favored calving
areas in the Matanuska Valley and along the Railbelt were made between
May 20 and June 4, 1957. These counts are summarized in Table No.lO.
Calving was in progress by May 20 and the counts indicated a ratio
of 14 calves per 100 cows. This ratio increased to 41, 57, and 52
per 100, respectively, on succeeding counts. The above ratios are
actual calf:cow observations, with twins considered as one incidence
of pregnancy.
Cows about to give birth and those with newborn calves generally
frequent lowland areas. The lowlands are generally swampy and
frequently are covered with 8-20 inches of water in the spring of the
year. The overall vegetation varies greatly but in general gives the
impression of a patchwork of spruce islands and heath, sedge and
sedge-bog openings, with dense borders of alder and willow. The
calves are frequently hidden inthe alders or in the spruce islands
and are also very difficult to see in the heath or sedge openings if
they are lying down. Cow moose exhibit no definite response pattern
to airplanes. Most cows with calves, however, either run to the calf
or face in the direction of the calf. When the cow refuses to run to
the calf or if the calf remains quiet, the observer frequently is unable
to decide definitely if a calf is present. The tendency of some cows
to hide their calves may seriously hamper aerial calf:cow counts.
At present it is not known what age group of calves are most frequently
hidden, or if a specific age group is involved. The time of day that
the counts are made may also influence the distribution and activity
of cows, cows with calves, and calves.
The estimated .calf:cow ratios in Table No .. 10 are a result of
including the instances when no calf or calves were observed even
though the female responded to aerial buzzing in a manner that indicated
a calf was present.
The spring aerial calf:cow counts, which possess certain previously
discussed variables, show that 50 percent of the cows in the populations
counted have calves by late May (Table No.IO and Figure No. 6 ). Thus,
if moose have a gestation period of 240-246 days (see Gestation Period),
50 percent of the cows were bred prior to October 1.
-60-
Figure No. 6. Progression of moose calving.
60 alves/ 100 Cows
50
40
3
20
10
/
/
/
/
/
20 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 10
May June
-61-
Table No.10. Progression of moose calving as revealed by aerial
calf:cow counts in the Lower Susitna Valley.
Observed Estimated
Date ~ w/0 ~ w/1 ~ w/2 Calf :Cow Ratio Calf :Cow Ratio
5/20/57 57 7 1 14:100 14:100
5/24/57 69 21 3 26:100 53:100
5/29/57 28 27 6 54:100 69:100
6/4/57 29 25 6 52:100 78:100
C. Embryos and Fetuses Collected. Another indication of
conception dates and period of successful breeding is obtained from
the estimated growth curve established from the measurements of
63 unknown-age moose fetuses (Figure No. 7 ). In general this
treatment is patterned 'after Armstrong's ( 1950) work with white-tailed
deer. The total length measurement (following the body contours)
was used to establish the points for the growth curve, instead of the
crown-rump or forehead-rump measurements used by Armstrong,
because, on moose, this measurement was more sensitive and more
reliable. The total length measurement is believed to be superior
to the forehead-rump measurement because the points of reference,
the tip of the nose and the tip of the tail, are more easily and accurately
located than are the forehead-rump points of reference which are the
intersections of the coronal and sagital sutures of the skull and the
tuberosity of the ischium. Another factor favoring the total1ength
measurement is the tendency for fetus to assume a "C" shape when
preserved. This tendency does not affect the total length measur~ment
but does affect the forehead-rump measurement.
Since no known-age fetuses are available for comparison and
because there is no possibility of obtaining any, at present, it was
necessary to make several assumptions in constructing the growth
curve from the present data. The assumptions are based on the most
complete available information and are as follows:
1. The embryo-fetus transition in moose occurs between 40-43
days, probably about 42 days following conception.
2. The gestation period for moose is 240-246 days.
3. That all fetuses grow at approximately the same rate.
-62-
900 mm.
750
6
b. 4
1./j
I
300
15
Figure No. 7. Average growth curve for .moose fetuses based on total iength
measurement of 63 embryos and fetuses.
•
•
(Circles represent, averages by periods)
eptember October January February March April
•
•
May
1. Embryo-Fetus Transition. The embryo-fetus transition is
an arbitrary but useful designation and has been described by Winters
( 1942) as that time at which organogenesis is complete and the remaining
fetal growth is largely development of existing organs.
The embryo-fetus transition for white-tailed deer,, cattle, and
sheep is estimated by Armstrong (1950) and Winters (1936, 1942) to
occur at 37, 45, and 34 days, respectively. The period of the
embryo occupies about 18 percent of the total gestation in the
previously discussed mammals. Applying this figure to the moose's
gestation period of about 240-246 days indicates that the embryo-fetus
transition would occur at about 42-43 days following conception.
2. Gestation Period. The assumption that moose have a
gestation period of 240-246 days is based on estimates by a number of
writers none of whom cite specific examples. Peterson (op. cit.).
3. Rate of Growth. The assumption that fetuses tend to grow
at the same rate is based on the observations of Winters (1936, 1942)
and Armstrong ( 19 50}. The pr eviou sly mentioned workers concluded
that fetus size is primarily a function of growth time and that while
individual variations and variations between single and multiple
pregnancies do exist, these variations do not significantly affect the
generalized growth curve.
The curve which was fitted to the embryo-fetus data, illustrated
in Figure No. 7, uses October 1 as its origin. This is an arbitrary
date, but data presented in. the previous sections on testis weights
and parturition dates tend to substantiate an early October peak of
. conception. In addition the sizes and development of the embryos and
fetuses collected in October and November indicate conceptions in
late September and early October. It is realized that the peak of
conception may not fall on October 1, but all available data indicate
this is a reasonable approximation. If the curve in Figure No.7
accurately reflects the growth of moose fetuses then important
information pertaining to the duration and peak of conception can be
obtained from it. If the growth curve is used as a constant to which
the other fetuses are compared, then all fetuses lying to the left of
the curve were conceived prior to the average date, and all fetuses
to the right of the curve were conceived after the average date. The
variance in time of conception, measured in. days, can be obtained by
dropping two straight lines to the abscissa of the curve. One line is
dropped from the point representing the total length of the fetus. The
other is dropped from the point on the average curve equal in total
length to that of the fetus in question. The distance between the two
-64-
lines represents the difference in time of conception. The scale on
. Figure No. 7 provides a means for translating the distance into days.
The data obtained from determining the variance in conception
. dates are illustrated in Figure No. 8. The average growth curve was
constructed by combining the daily percentages into three-day periods
and plotting them as a frequency distribution. These data reveal that
60 percent of the fetuses in this sample were conceived in a 10-day
period; that 80 percent were conceived within a 15-day period; and
that all individuals in this sample were conceived within a 40-45-day
period. This curve indicates that the peak of conception occurs in
early October. This is in agreement with the peak of testis
development (Figure No. 5) and the peak of calving (Figure No. 6 ~·
If the curve and the October 1 starting point are essentially
correct then the earliest conceptions occur in mid-September and the
latest in late October, roughly a period of 40-45 days. This period
indicates one or possibly two additional oestrous cycles in moose not
conceiving during their first oestrous, or an extended period of
ovulation possibly due to age-differential ovulation.
Deer are known to experience several oestrous cycles annually
if they do not conceive during the first (Cheatum 1946). Data
illustrating additional oestrous periods in moose are very meager.
Examination of the ovaries from a Class IX female killed on
November 14, 1956, at Mile Post 184.4 on the Alaska Railroad
revealed what appeared to be a degenerating corpus luteum of oestrous
and a developing follicle which burst when handled. It is believed
that this animal was about to ovulate. No other examples possibly
illustrating a second oestrous are known to this writer. However, the
uniformity of the conception dates of three fetuses which fall far to the
right of the average growth curve suggest a possible second oestrous
in Alaskan moose. The data, based on fetus size distribution, from
moase in the Wells Gray Park in British Columbia clearly indicate
at least three oestrous cycles (Ritcey and Edwards, personal
communication).
Data suggesting an age-differential ovulation are similarly
meager. Fetus no. 979, Table No.ll, from a Class I female was
probably conceived late in October. Female No. 806, Table No. 1Z,
collected November 10, 1957, also a Class I individual, had ovulated,
but the corpus luteum had not completely lutenized, suggesting a
recent ovulation. The sizes of the fetuses from Class II and Ill females
appear to be randomly distributed (Table No.11). Yearling females
possibly ovulate later than older animals, but since few of them ovulate
-65-
Table No. 11. Moose fetus data.
I Measurements in millimeters
Collection Zygo. Weight Age of Ace.
Date Ear H. F. H.L. F.L. T.L. H. C. Girth Sp.Pb. Arch (Lbs.) Sex Female No.
10/31/57 20 ?2 II 677
11/1/56 10 III-IV 302
11/3/57 6 ? XI 676
11/20/56 35 ? II 315
11 /'(.4/56 37 ? VIII 286
12/25/56 15 60 80 80 250 135 145 100 32 0-7 cf VI 307
1/6-9/58 15 60 84 82 267 129 142 107 30 cf IV 976
1/6-9/58 15 59 84 83 266 127 141 105 34 ~ IV 976
1/9/58 7 27 42 42 156 87 92 61 24 ~ I 979
1/9/58 22 87 118 117 328 154 195 132 41 5f Unkn. 981
I 1/8-9/58 20 79 106 108 294 149 H~8 123 38 cf v 980
0' 1/10/57 19 65 97 95 270 145 170 110 35 0-11 ~ IV 422 0'
I 1/10/57 19 65 100 95 275 150 175 130 37 0-12 cf IV 422
1/16/57 71 140 34 cf 344
1/18/56 75 112 95 305 35 0-11 ~ III· 187 .. ,3
1/23/57 23 90 125 120 350 170 200 160 42 1-4 ~ IV 330
1/25/57 26 100 140 135 . 355 175 215 150 46 1-9 cf v 435
1/26/57 37 115 155 145 400 200 230 190 46 2-0 ~ VI 3.37
1/29/57 105 135 350 190 220 180 45 1-12 ~ III 355
1/29/57 41 125 185 175 455 220 255 200 51 2-11 cf III 336
2/1/57 42 125 170 160 460 210 255 205 50 2-9 ~ IV 358
2/1/57 41 125 165 170 440 215 255 195 50 2-10 ~ IV 3.58
2/I/57 33 105 145 145 395 185 220 190 45 1-14 .d v 349
2/1/57 33 105 145 135 385 18-5 210 165 44 1-9 cf VII 347
2/1/57 32 105 150 140 375 185 205 180 46 1-9 cf VII 347
Table No. 11 (Continued).
Measurements in millimeters
Collection Zygo. Weight Age of Ace.
Date Ear H. F. H.L. r ...... L. T.L. H. C. Girth Sp.Pb. Arch (Lbs.) Sex Female No.
2/4/57 45 135 170 450 220 250 190 54 2-14 c! III 367
2/4/57 38 115 160 155 430 205 250 200 49 2-6 c!
2/4/57 42 120 180 170 440 225 250 51 2-13 c! IV •. 37'3
2/4/57 38 120 160 150 440 210 25Q 180 49 2-5 c! v 365
2/4/57 36 120 165 150 430 205 230 185 so 2-5 c! v 365
2/6/57 44 125 175 165 415 220 275 190 54 3-2 ~ VIII 329
2/6/57 42 115 180 160 400 195 230 165 52 2-4 ~ IX 341
2/6/57 44 125 185 175 240 225 51 ~ III 388
'2/9/57 38 135 205 165 440 210 250 185 49 ~ 390
2/9/57 40 130 205 170 405 220 255 195 50 ~ 390
2/13/57 40 145 210 190 480 230 285 210 52 3-6 ~ IV-V 378
I
0' 2/14/56 155 230 200 461 64 4-3 ~ VI 199.3
...J
R 2/14/57 53 155 230 210 510 240 285 220 59 4-7 c! 382
2/19/57 54 148 200 195 505 225 300 230 59 2-10 c! IV 434
2/21/57 50 140 200 190 470 230 275 195 54 3-6 ~ IX 398
2/21/57 50 145 220 185 500 220 300 180 53 3-5 ~ IX 398
2/24/56 155 240 210 495 58 4-11 c! IV ~94
Feb. 56 165 250 215 500 65 c! Unkn. 209
3/2/56 185 280 240 520 65 5-15 ~ IV 202.3
3/2/57 45 155 210 185 480 zzo 290 210 58 3-15 ~ II-III 401
3/3/56 195 315 260 610 69 7-2 ~ v 212
3/4/56 195 310 260 610 69 6-11 c! VIII 208.4
3/4/57 75 219 295 275 610 260 390 280 8-7 c! II 415
3/5/57 75 200 290 270 600 290 360 270 69 7-10 c! v 414
3/9/56 205 330 285 627 72 7-14 c! VII 211.4
Table No. 11 (Continued).
Measurements in millimeters
Collection Zygo. Weight Age of Ace.
Date Ear H. F. H.L. F.L. T.L. H. C. Girth Sp. Pb. Arch (Lbs.) Sex .Female No.
3/9/57 70 205 280 265 280 67 7-0 ~ VI 417
3/12/57 78 215 290 285 640 275 370 305 72 9-9 cf Ill 429
3/14/57 64 200 265 25o 615 255 340 290 70 d IV 430
3/14/57 65 195 265 250 600 255 330 270 71 6-14 d IV 430
3/19/57 68 200 270 255 590 265 340 351 68 8-4 ~ I 428
3/19/57 80 225 335 290 700 2.70 350 290? 10-8 ~ v..,.vi
March 56 195 290 255 580 67 d Unkn. 208.7
March 56 215 320 280 650 71 7-12 ~ Unkn.
4/2/57 100 280 395 375 780 305 430 360 80 13-0 d VI 448
4/9/57 111 330 450 430 820 320 450 410 90 19-5 d IV 450
n 4/10/56 320 480 415 810 82 14-0 ~ III 190.4
~ 4/10/57 104 290 370 360 780 310 410 350 78 15-0 ~ IX 451
a 5/2/56 335 500 435 790 81 14-0 ~ VIII
5/2/56 310 455 395 740 81 14-0 d VIII
Fetuses from Fairbanks
1/29/55 20 70 102 99 280 131 156 117 40 0-11 ~ Unkn. JLB2.85
2/21/55 44 135 199 193 420 211 269 183 56 3-2 d Unkn. JLB291
March 69 185 268 257 640 263 332 . 263 69 7-0 ~ Unkn. JLB290
March 68 190 269 640 262 334 7-2 d Unkn. JLB289
3/19/57 80 225 335 290 700 270 350 290 10-8 ~ Unkn.
1 Measurements follow those described by Winters (1936), Winters. et. al. ( 1942).
2 Identification of sex by external anatomy impossible at this stage of development.
Figure No. 8 . The peak and duration of successful conception in moose
. as measured by the variance in total length of 63 fetuses
which were compared to the "average growth curve" in
Figure No. 7 •
50 (;Percent of total conceptions)
40
30
12 9 6 3 0 3 6 9 12 15 18 21 24 27 30.
Sept. 19 Oct. 1 Nov. 1
-69-
this does not markedly influence the age-size distribution of the
fetuses. It is probable that the range in fetus sizes and conception
dates is caused by cow moose experiencing additional oestrous cycles,
ifthey do not conceive during the first cycle, and by normal variation
in oestrous dates.
D. Analysis of Ovaries. During this study 31 pairs and five
individual ovaries were collected from 36 moose Age Class I or older
(Table No.l2).
Connective scar tissue formed by the degenerating corpora lutea
of pregnancy, the corpora albicantia, has been used by Cheatum ( 1949)
to estimate the previous year's reproductive performance of certain
white-tailed deer populations. In identifying the number of corpora
albicantia present it was necessary to assume that all pigmented scars
present represented the past gestation period us corpora lutea of
pregnancy, and that the pigmented scars resulting from other ovarian
functions could be eliminated on the basis of their smaller size.
Galley ( 1957), working with black-tailed deer, presents data which
indicate that some pigmented scars from ovarian functions other than
pregnancy are present and that the fate of the corpora albicantia of the
corpora lutea of pregnancy is not consistent. In black-tailed deer,
this resulted in 18 percent more corpora albicantia being tallied in
ovaries collected during the anestrous period than there are corpora
lutea of pregnancy present in ovaries collected during the gestation
period.
Seventy-nine moose ovaries listed in Table No.lZ were sectioned,
sagitally, with a razor blade and examined for the presence of corpora
lutea of pregnancy and for corpora albicantia of corpora lutea of
pregnancy. The sections were of varying thickness, but were thin
enough t.J allow the passage of light and thereby permitted detection of
pigmented bodies and large follicles.
In moose the corpus : luteum of pregnancy is large, frequently
10-18 millimeters at its greatest diameter, and is easy to find. The
corpora albicantia of corpora lutea of pregnancy are smaller, dark,
pigmented scars, varying in color from light brown to almost black.
The usual size was from 4-8 millimeters at the greatest diameter.
Occasionally smaller pigmented bodies were observed, but these were
not counted (Cheatum, op. cit., and Galley, op. cit.).
Examination of the moose ovaries collected during this study
revealed _a number of interesting data; of particular interest are the
following:
-70-
Table No. 12. Notes on size and development of moose ovaries.
Wt. of I Wt. of II Diameter
Ace. Ovary Ovaxy Corpus luteum No. of No. Corpus of largest Date of
No. Age of~ {mg) . (l!J.g) of Pregnancy . Fetuses Albicans Follicle{mm) . Collection
323 Calf 650 Lost 0 1 12/18/56
301 Calf . 950 0 None None 1 12/23/56
301 II 900 0 II II 1 12/23/56
! ·~
327 Calf 1000 0 n II 2 1/26/57
327 " 1000 0 II II 2 1/26/57
223.5 Calf 1000 0 II " 1 2/3/57
/ 223.5 " 950 0 II II 1 2/3/57
8
-J ..... 379 Calf 1400 0 II II 1 2/13/57 I
379 II 1400 0 II II 1 2/13/57
389 Calf 350 0 II II 1 2/14/57
389 II Lost 0 II II 1 2/14/57
543 I 1800 0 II " 7 8/31/57·
543 II Lost
536 I 1250 0 II II. 1 9/2/57
536 II 600 0 II II ? 9/2/57
B-25 I 1100 0 l·t " ? Fall 1957
B-25 " Lost
Table No. 12{Continued).
Wt. of I Wt. of II Diameter
Ace. Ovary Ova,ry Corpus luteum No. of No. Corpus of largest Date of
No. Age of~ (m~) (m~J of Presnancx: Fetuses Albicans Follicle( rom) Collection
806 I 3350 1 1 ? None z .. 11/10/57
806 II 1300 0 None II . 2.· 11/10/57
840 I 1050 0 II II 2 11/24/57
840 II Lost 11/24/57
313 I 2700 0 II II 1 12/18/56
313 II 2700 0 II II 1 12/18/56
342 I 1250 0 II II 6 1/17/57
B 342 II 1200
-.1
0 II II 2 1/17/57
N
D
990 1 0 II II ~·· 1/2.4/58
990 II 0 II II ~·· 1/24/58
428 I 3550 1 1 II 10 3/19/57
428 II 1875 0 None II 4 3/19/57
513 II 2350 0 II , II. 9 9/2/57
513 II 1850 0 II 1 7 9/2/57
677 II 2 1 1 None 6 10/31/57
677 II Lost
415 II 3650 1 1 1 ? 8 3/4./57
415 II 1800 0 None 1 3/4/57
Table No. 12 {Continued)
Wt. of I . Wt. of II Diameter
Ace. Ovary Ovary Corpus luteum No. of No. Corpus of largest Da~e .. of
No. Age of !'l (mg) (mg) of Pregnancy Fetuses Albicans Fo1~icle{mm) Coll~ction
559 II-III 2100 0 None None 9 8/24/57
559 II 2650 0 ,, 2 11 8/24/57
979 II-III 1150 0 II 1 1 1/9/58
979 II 2600 1 1 None 4·· .. 1/9/58
401 II-III 3550 1 1 2 8 3/2/57
40l II 1615 0 Non~. 1. 4 3/2/57
528. III-IV 2650 0 None None 12 8/22/57
I 528 II 2000 0 " 2 3 8./22/57
~
I./.)
I
302 III-IV 5350 1 1 None 20 11/2./56
302 It 4000 0 1 II 20 11/2/56
378 IV-V 4900 1 1 4 5 2./ 13/ .?7
378 II 2.700 0 1 4 9 2/13/57
430 IV 1950 0 2. _4.,.5 4 2/ 16/57
430 II Lost
177 IV 3450 1 1. None 3/2/56
177 II Lost
450 IV 4300 1 1 " 7 4/9/57
450 II 1750 0 1 1 1 4/9/57
Table No. 12 (Continued)
Wt. of I Wt. of II Diameter
Ace. Ovary Ova•:y Corpus luteum No. of No. Corpus oflargest Date of
No. Age of~ (mg) (mg~ of Presnancy Fetuses Albicans Follicle(mm) Collection
595 V-VI 4050 0 None 3 4 10/2/57
595 II 5150 0 II None 10 10/2/57
980 3 v 3250 0 " II 14 1/9/58
980 It 6550 2 1 II .3 1/9/58
191 v 5700 1 1 1-2 .6 3/3/56
191 II 3150 0 1 1 . 1 3/3/56
414 v 4700 1 1 3 7 3/5/57
n 414 -J II 2250 0 1 3 1 3/5/57
~
I
521 VI 4400 0 None 3 9 8/2.5/57
521 II 5000 0 II 7 5 8/25/57
531 VI 2800 0 II 4 3 9/2/57
531 II 3050 0 II 2. 14 9/2/57
586 VI 3300 0 II 3-4 7 9/15/57
586 11 3000 0 It .3 3 9/15/57
222 VI 4900 1 1 ,5 6 3/4/56,
222 II 2600 0 None 4;, 2 3/4/5,6
417 VI 4500 1 1 4 4 . 3/9/57
417 II 3750 1 1 5 3 3/9/57
Table No. 12 (Continued)
:Wt. of I Wt. of II Diamet.er
Ace. Ovary Ova.:y Corpus luteuin No •. 'of . No. Corpus of largest. Date of
No. Age of~ .(mg) (mg) of Pr~sn,ancy Fetrises Albicans Fol~iCle(mm) .CollectiQn
4 . ' .•
448 VI 3400 1 1 . 4-5 4/2/57
448 tl 1650 0 None 3 4/2./57
500 VII 2300 0 Lactaf.ing 3 4 6/9/57
500 II 2750 1 Lactating 3 4 6/9/57 ; .: .. , ~ .
184.4 VIU-IX 2650 14 None·· 6-7 ll/15/56
184.4 II 1500 0 II 5 .6 11/15/56 .·
676 IX 5450 1 1 4-5 3 11/3/57 ..
676 11 4250 0 None 3 7 ll/3/57 I
-.,]
:·' IJ1 . ··-·
I 976 IX 3450 1 1 6 ?. .r/6-9/58
976 II 3750 1 1 7 7 1/6-9/58:
341 JX 5500 l 1 4 5 . 2/6/57 ..
341 II 3500 0 None 2 .. 10 2/6/57
398 IX 5450 2 2 '1 5. 2/21/57
398 II 2400 0 None 4 10 2/21/57
451 IX 4000. 1 1 4 7 4/10/57 '.. ,. '
451. II 2150 0 None 6 :.1 4/10/57
~ Not definitely pregnaJilt; had ovulated~
Partially destroyed. .. . · ..
3 Had decompos.ed somewhat--ideiit~fi~ation o.f corpora albicantia not possible.
4 May be corpus luteum ofoestrous:;.n.ot ofpregnancy.
5 Did not complete dissection of this ovary.
1. Development of the follicles and time of ovulation.
Z. Age of animal--number of corpora albicantia COfrela~ion.
3. Types of ovulation.
1. : FoUicl~ d.evelopment and ovulation. · Originally it was thought
that a collection ·of ovaries from late August to October would help
establish the period of successful breeding and conception. However,
only ten sets of ovaries from this period have been collected. All
ovaries from animals older than Class I had one or more developing
follicles (Table No. 12). The follicles ranged from 3 to 14 millimeters
in diameter~ One Class I female had· a developing follicle 7 millimeters
in diameter. The ovaries from a Class VII individual collected in early
June contained several small follicles 4 millimeters in diameter. It.
is not un-q.sual for ovaries taken from pregnant cows to have follicles
up to 10 millimeters in diameter.
m spe-cimens 531 and 586, collected in September, the follicle wall
was very thin. Female No. 595 collected on October 2, 1957,. had
three large follicles, one of which ruptured when handled. Although all
the ovaries collected during this period had large follicles pres.ent, tpe
data are too limited to indicate trends on ovulatioll; dates.
. Z. Age of animal--number of corpora albicantia. The number
6f corpora albicantia or pigmented scars in moose ovaries has a
direct relationship to the age of the individual (Table No. 8 ). This
suggests that, in moose, the corpora albicantia of corpora lutea of
pregnancy persist for a considerable time and possibly throughout the
e~.nimaPs life. However, estimating past reproductive success from
pigmented scar counts other than in a general way is not considered
feasibl~ in moose because they exhibit multiple ovulation. Thus, if
tw9 or more ova are released ~imultaneously and only one is
su~cessfully fertilized the remaining corpora lutea of oestrous will
lutenize and become corpora lutea of pregnancy although not
representing a fetus. Ultimately they become corpora albicantia and
would introduce an error in an estimate of past reproduction success
based on corpora albicantia scar counts ..
3. .Types _?.f ov~ation. The number of corpora lutea of pregnancy
prese:nt in moose ovaries usually corresponds to the number of fetuses
present. Thus if twin fetuses were present two corpora lutea were
present; however, s,everalvariations were observed. One pair of
ovaries had a single corpus luteum and twins were present; another had
two corpora lutea and a single fetus although no evidence of absorption
of a second fetus was observed in this animal. In the case of twin
fetuses, the ·corpora lutea were located one in each ovary, two in one
ovary, a:nd as previously mentioned, one instance of a single corpus
luteum. -76-
Cheatum ( 1949) indicates that corpora lutea of oestrous not
resulting in pregnancy do not form pigmented scars. Several sets
of ovaries from cows collected in October and November were examined
and what appeared to be degenerating corpora lutea of oestrous were
present, but at this stage it was impossible to determine if the scar
tissue would be pigmented. Also, it was·considered possible that the
embryo was not yet attached to the uterine wall and lost in examination,
and in one instance the cow was believed to have experienced an
abortion or resorption.
Other Observations on the Progress of Rut Activities
Additional observations on the progress of rut were obtained
from field examination of hunter killed animals and from aerial sex
and age composition counts.
On September 17 this writer killed a yearling bull which had one
large cow accompanying it. The pair were observed for 30-45 minutes
before the bull was shot. During this period the male evidenced mU.ch
interest in the cow but did not attempt to mount her. Examination of
his stomach contents revealed he had ingested some urine--typical
of rutting bulls. On September 20 R. 0. Skoog killed a 3-4 year old
bull near the Susitna River bridge along the Denali Highway. He
reports that this bull had ingested a considerable amount of urine.
Aerial sex and age composition counts of the moose populations
inhabiting the Clear Creek and Maclaren River drainages on October 8-9,
and on the Susitna River area October 10 tallied 456 animals (see Sex
and Age Composition Counts, Upper Susitn.a~Copper River Valleys).
Most, 76 percent, of these animals were found in "harem-like" groups
of 3-21 animals. The moose were generally distributed along the
creek b0~toms in dense willows 6-12 feet high.
Moose were under almost continuous observation for eight hours
but no bulls evidencing interestcin cows were seen. In: fact some of
the large bulls were leaving-the breeding groups and others were
beginning to eat again. suggesting that the period of active rut was
past.
Evidence of recent rutting activity was abundant on willow-and-
alder-covered benches some 200-400 feet above where the majority of
the moose were tallied. Nearly 100 rut pits {11 brunstgropen") were
counted. These excavations are reportedly made by bulls alternately
pawing, urinating and rolling in them during extreme exci~ement of
the rut {Peterson 1955).
-77-
Mating reportedly takes place in the immediate vicinity of these
pits (Lonnberg, 1923). This area was covered by 3-4 inches of snow
s,ome 3 to 4 days previous to the counts. Fresh trails led from the
breed~ng area to where the moose had regrouped in the valley areas,
a distance. of approximately 1-2 miles. The presence of rut pits and
the subsequent movement of th~, moose to another area also suggest
that the peak of the breeding portion of the rut had pas sed.
Discussion of Rut
The breeding activities of the moose inhabiting, the Railbelt and
Matanuska Valley moose populations commence in early September,
when the bulls first start polishing or rubbing their antlers, and
continue through September, October, and early November.
Spermatogenesis, as evidenced by presence of spermatozoa in
the epididymis has begun at ~east by August 20 and continues at least
until December (Table. No.7). Examination often sets of ovaries
in August and early September revealed that developing follicles were
present but that none of the females had ovulated.-One set of ovaries
collected on October 2 had not ovulated, but the largest follicle
ruptured when handled, possibly indicating that this cow was about to
ovulate.
The combined data of testis weights, parturition observations,
embryo and. fetus measurements, ovarian analysis, and field
observations, indicate that the peak of conception occurs sometime in
late September or early October, probably about October l-3. It is
estimated that 80 percent of the fetuses in this sample were conceived
w.ithin .a 15 day period and.that all of thetn. were conceived within a
40-45 day period. This suggests that most females are bred during
their h:.-st oestrous, but that subsequent oestri may occur if the female
does not conceive during the first. It is also possible that the length
of the period of conception is caused by age-differential ovulation.
Possibly, both additional oestrous cycles and age-differential ovulation
account for the extended period of successful conception.
Fertility Rate~ Pregnancy data were obtained from 98 moose
during the winters of 1955-56, 1956-57, and 1957-58. These moose
were examined as a result of highway, railroad and illegal kills, and
all were examined between late October and May when moose are
pregnant. In most instances complete information was available and
jaws, ovaries and fetuses, if present, were collected. The "barren
cow moose" is a concept apparently accepted by many; theoretically,
under certain adverse conditions a large percentage of the herd could
-78-
Table No.13. Comparative reproductive data from 98 cow moose of Age Class I-IX
Percent•
Percent Total Total N(). ·Twins:
No. . This Sets of Barr.en No. Fetuses Fetuses: Preg. 100
,·;,
Age Class Cows Sample Twins Smgletons Cows Fetuses This ·sample 100 Cows, Cow.s Pregnancie:
I 5 5 0 1 4 ·:I . 9 20 '1 0
II-III 17 17. 5 1 14 2 16: 14.3 94 15 7
IV-V 30 31 9 21 0 39 3_4.· 9 130 ~0 30
VI-VII 14 14.5 2 11 1 15 13.3 107 13 .15
0
-.J VIII-IX 17. 5 8. i9.7 129 -D 17 7 2 Z2 15 47
i
Unknown 15 15. 5· 5 '9 1 19 16.9 .' 127 14 36
98 100 24 64 10 112. 100 115 88 . 27
'·
Excluding Class I 123.
Fetuses :100 Pregnancies 129
Pregnancies :100 Cows 90
<' ,, •• '
Excluding-Class I Individuals 94
remain barren or lose their fetuses as a result of diseas_e or
malnutrition. This, however, does not appear to be a problem in the
Matanuska_ Valley and Railbelt areas, where the bull:cow ratios are
as low as 7 per 100 in some localities and where available winter
browse appears to be a limiting factor in other localities, as 88 of 93
(95 percent) of all cows older than Age Class I were pregnant-(Table No.I3).
The present technics employed to age moose are 110t sufficiently
accurate to assign a specific year to an age class. The ag'e classes
probably include several year classes, particularly in the older age
categories (see Sex and Age Composition section). Thus, in an effort
to measure the relative calf production of young and old moose and to
minimize the aging technic problems, the eight recognizable age
classes of breeding age females were lumped into four a:ge categories.
Yearlings, or Class I, individuals were conside'£ed separately (Class I
individuals are discussed in Age at Sexual Maturity section). :
The age category of Class II and III individuals, unfortunately
the most difficult_ age classes to separate, i~cludes the period at;which
female moose reach sexual maturity (see Age at Sexual Matu~ity),.
The category of Age Classes IV and V, which probably includes
moose of 3 1/2 to 6 l/2 years, coincides with early physical prime,
and is represented by 30 individuals. No barren cows were found in
this group.
The age category compo~ed of Classes VI and VII probably
represents moose of 6 1/i.to 10 1/2 years; only one of 14 other animals
examined was barren.
The oldest group, Age Classes VIII and IX, probably represents
moose l') 1/2 to 20 years old; only two of 17 cows examined were
barren.
Although the present data are lim~ted in number, there is no
indication that female mo()se live past their reproductive age even though
hunting is not at present used to manipulate the age structure of the herd.
O:n.ly one of 15 {above Age Class I) unknown-age females was
barren. Thus, as mentioned earlier, 95 percent of all female moose
examined, above Age Class I, were pregnant.
Another important factor in evaluating the relative reproductive
importance of each age category is the number of calves produced.
This is expressed as calves per 100 cows and the barren cows are
-80-
included in the computations (Figure No. 9 ). These data reveal that
the younger age groups, Age Class I and Age Classes II and III,
produce fewer calves and that the oldest age group, VIII and IX,
continue to produce calves.
The rate of twinning is still another factor relative to the
importance of a particular breeding age group. Figure No.9 indicates
that the youngest breeding age group, Age Classes II and III, has the
lowest rate of twinning as well as the lowest calf:cow ratio, excepting
Class I individuals which are not considered a breeding age group.
The oldest age group has the highest rate of twinning; 47 sets per. 100
pregnancies.
The age category composed of Age Classes VI and VII, presumed
to represent moose in late prime of life, is difficult to interpret as
both the calf:cow and twinning rate are lower than expected. This is
probably the result of a small nonrepresentative sample.
These data indicate that potential reproduction in the Railbelt
and Matanuska Valley moose populations is very good; that great
hunting pressure, even reducing the bull:cow ratio to 10 per 100 or
less has not lowered the fertility rate of the moose populations; and
that hunting only bulls is not an effective means of controlling moose
numbers.
-81-
Figure No. 9 . Comparative potential reproduction of five age
categories of cow moose.
Age
150 -
12..5.
IUD_
5..0..
Fetuses/ 100 cows and
twins/ 100 pregnancies
Ill
Classes I II & III IV & V
I
I
Fetuses per 100 cows
Twins per 100 pregnancies
-82-
VI & VII VIII & IX
Sex and Age Distribution of the Matanuska Valley and Railbelt Moose
Populations
Sex and age data were obtained from 476 moose, from Age Class
Fetus to Age Class IX, the oldest recognizable age category (Table No. 14).
The, sex and age information for Age Classes Fetus and Calf represents
all specimens collected, and includes animals collected as a result of
railroad and highway accidents and illegal kills. The specimens
represented in Age Classes I-IX were killed by trains during the
winters of 1955-56 and 1956-57 between Mile Posts 150 and 250 on the
Alaska Railroad.
Sex Ratios. Initial sex ratios of many mammals, including cervids,
approximate a 1:1 ratio with, perhaps, a slight numerical superiority
of males indicated for some species. Sex ratios at conception indicate
a definite male superiority in numbers, under certain favorable conditions,
but sex selective mortality factors tend to reduce this superiority even
during the prenatal period. Robinette, et. al. (1957), working with
mule deer,. presented a review of the literature on sex differential
mo·rtality as well as considerable quantitative data on mule deer sex
ratios, both pre-and postnatal. The literature and data presented
. show that there are exceptions to the general belief that males outnumber
females at birth. This is especially apparent when dealing with local
populations. Some factors which may influence the initial male:female
ratio are as follows: age structure of the population, ·average age and
past reproductive history of the females, the plane of nutrition before
and after conception, and the severity of winter during the gestation
.period. Although these factors can affect the male :female ratio at
birth, there seems to be no way to predict which sex will be favored;
generally, however, the male suffers the greatest mortality.
Robinette, et. al. (op. cit.) indicate that postnatal sex selective
mortality factors in mule deer apparently affect males at a greater
rate during the early months, but that females die at a greater rate
during the first winter. This is reversed during the second winter.
During this period the mortality loss rate for males is roughly twice
that of females.
The present data on the sex ratio of moose fetuses are limited,
but information from 63 fetuses indicate:\; a sex ratio of 103 males per
100 females. The sex ratio of 14 sets of twin fetuses was 16 males
to 12 females or 133 males per 100 females. The sex composition of
the 14 sets of twins was as follows: males, 5 sets; mixed, one male
and one female, 6 sets; and females, 3 sets.
-83-
The sex ratio of 129 moose calves, varying in age from one to
ten months, was 64 males to 65 females or 98 males per 100 females.
This is essentially a I ~1 ratio, as was found in the prenatal specimens,
with only a slight indication of excessive male mortality.
The sex ratio of animals older than calves is distorted by hunting.
The influence of hunting on the sex ratios of the moose populations
is illustrated by dividing the study area into three local areas which
. are subjected to varying degrees of hunting pressure. The criteria
for separating these areas are based on aerial sex and age counts,
observations on winter migrations and upon known accessibility to
hunting. The areas are as follows~ Area I, the Matanuska Valley,
Mile Posts 150-175 along the Alaska Railroad; Area II, the Willow
area, Mile Posts 176-200 along the Alaska Railroad; and Area III, the
Kashwitna-Talkeetna area, Mile Posts 20 1-250 on the Alaska Railroad.
These areas represent moose populations subjected to intense, heavy,
and practically no hunting pressure, respectively.
The moose represented in Table No.l4, ·above Age Class Calf,
were killed by trains during the winters of 1955-56 arid 1956-57. The
eight age classes above Age Class I have been combined into four age
categories in an attempt to compensate for the aging technic difficulties
(see Age Distribution). Although the samples from each local area
are small, the effect of hunting on the male segment of the moose
populations in Areas I and II is very apparent. The bull :cow ratio in
Areas I and II are 21 and 38 bulls per 100 cows, respectively. The
assumption that sex ratios obtained from examination of train killed
moose are representative of the existing moose populations is supported
by the sex ratio data obtained from aerial sex and age counts made on
approximately the same local moose populations (see Sex and Age
Composition in the Lower Susitna Valley). The sex ratios obtained by
the two sampling technics are similar. The overall bull~cow ratio
as indicat~d by the railroad kill is 57 bulls per 100 cows. The same
ratio obtained from aerial composition counts is 44 bulls per 100 cows.
The two samples are not directly comparable. however, because most
of the railroad sample came from Area III which. is not hunted, whereas,
over half of the aerial sample represents a heavily hunted area.
Nevertheless. trains appear to sample proportionately the moose
populations inhabiting the areas adjacent to the right-of-way.
The sex ratio in Area III, which supports very little hunting, is
84 bulls per 100 cows, approaching a 1 ~1 ratio, but showing a definite
indication of excessive male mortality. The sex ratio of the three oldest
age classes, 46 bulls per 100 cows. suggests that sex selective mortality
factors affect males. However, even relatively light hunting would
-84-
distort the sex ratio; particularly that of the older age categories.
The sex ratio of the yearling class, which indicates a surplus of
males, is confusing. The only logical explanation is that trains select
yearling males or, more plausible, that the sample is not representative
of the age class in question.
Sex ratios of moose appear to be essentially 1 ;1 with only a slight
indication of male superiority in numbers during the fetal stage and
a correspondi~g slight indication of excessive male mortality during
the first year of life. The sex ratios beyond Age Class Calf are
distorted by hunting, but in Area III where hunting is limited by
accessibility natural mortality apparently affects males at a greater
rate.
Age Distribution. Data on the age of 240 moose, Age Class I-IX,
were obtained from animals killed by trains between Mile Posts 150
and 250 on the Alaska Railroad. These data are presented in Table•Nos.
I4and 15.
Age determinations of moose based on comparative wear ofthe
mandibular teeth have been described by Skuncke ( 1949}, Lensink {19 55),
and Peterson (1955). All three of the aging technics are based on
diagnostic characteristics of tooth wear, and jaws evidencing similar
wear are placed in the same age class. Apparently, only. Skuncke had
some known age jaws for comparative purposes. All three of the
previously named writers describe nine general age classifications,
excluding calves of the year. In all probability only the first three
age classes correspond to the chronological age of the animal. In
analyzing the material presented here the writer first used a key, based
on a combination of diagnostic characteristics of wear, constructed by
Lensink (op. cit.). Subsequent cross checking by Lensink revealed
that complete agreement was not obtained even on Age Classes II & III
when using the key alone. Since comparative wear is difficult to
evaluate quantitatively, classification of jaws based on experience and
comparison with a set of known age or approximate age jaws seems a
more desirable technic. Quimby (1957) working with elk and having
known. age jaws for comparison concluded that no single characteristic
or combination of characteristics of wear satisfactorily separated
animals with "full mouths", and while not absolute, the best technic
was visual comparison with known age jaws. In his conclusion he further
states, 11 ••• familiarity gained by handling large numbers of jaws
seems to provide the best criteria for establishing age classes."
-85-
The latter, in combination with a jaw board of approximate age··
jaws, is the technic employed to classify the jaws discussed in this
section of the report. Age Class II and beyond undoubtedly includes
more than one year class. The overlap occurs because moose are
known to have a maximum life span of at least 21 years (Skuncke,
op. cit.). Thus, the seven age classes beyond Class II represent
moose from 3 to 20 years of age. In all probability the older age
classes represent 3-5 year classes.
Hunting changes the age distribution of the bull population. segment
and for this reason bulls and cows are considered separately in Table Nos.
14 and 15 •. Very few bulls survive to Age Classes VIII and IX in the three
local areas studied. The reason for the poor survival of bulls in
Area I and II is directly attributable to removal by hunting. The
mortality factors affecting bull survival in Area III are not known.
The status of the population as reflected by age distribution is
best assessed from age determinations .of the female segment, because,
as has been previously discussed, males are removed by hunting.
Again, the lack of accurate aging criteria, especially for year classes,
compounds the problems involved in. analyzing the significance of the
population age structure. The basic problem involved is determining
the exact number of year classes represented by a particular age class.
However, until known age specimens are available the desired breakdown
will not be possible and analysis of population age structure based on
the nine recognizable age categories or combinations thereof must be
considered as only a general indication of population age structure.
Several interesting popUlation trends are revealed through analysis
of the age structure of the 1955-56 railroad killed moose. The data
obtained from the 1955-56 kills are used instead of a cumulative total
kill for a number of years because of the desirability of analyzing the
fate of several important year classes. The 112 cow moose, Age
Class I-IX, killed by trains during the winter of 1955-56 are listed in
Table No.l6 by age class and percent of total. Analysis of these data
reveal that Age Classes I and II comprise only six and five percent,
respectively. of the total female population. This suggests poor survival
of these age classes. Cros.s checking with the 19 53 and 1954 fall
aerial sex and age composition counts made on these same areas
reveals that the calf~cow ratios were approximately 44 and 40 calves
per 100 cows, respectively. Thus, if the sample of railroad killed
animals is representative of the existing female population, great
mortality has occurred to these age classes. The unusually severe
winter of 1954-55 may have caused heavy mortality of calves and
possibly affected yearlings similarly (see Sex and Age Composition in
the Lower Susitna Valley». Unfortunately, quantitative evidence of
calf survival during severe winters is not available. Limited field
.~86-
observations made during the winter of 1955-56, when total snow
accumulation possibly exce.eded that of 1954-55, revealed that calf
and adult mortality may have been heavy, particularly in Areas II and
Ill. Area I, th~ Matanuska Vall~y. did not experience unusual snow
accumulations in 1955-56. Cow moose have a long reproductive life
span.and cons.equently the apparent poor survival of two successive
age cla~ses is not necessarily a serious loss in a well established
moose population (see Reproduction).
The age structure of the Railbelt moose populations, as indicated
by train killed moose for the years of 1955-56 and 1956-57 has a
preponderance of 11middle" to old age females. However, the age
structure of the cow segment of the three local populations is quite
different. In Areas I and II 58 and 51 percent, respectively, of the
cows are of Age Glass V or older, whereas in Area III only 38 percent
of the cows are represented in the older age classes. The percentages
of females in the, oldest age category, Age Classes VIII and IX, from
the three areas are as follows: Area I, 25 percent; Area II, 19 percent;
and Area ill, 11 percent. These data indicate that the age structure
of the population in Area III is considerably younger than that of
Area I. The most obvious differences between the two areas which
might affect population age structure are climatological. Area I, the
Matanuska Valley, is subjected to frequent strong winds throughout
the viri.nter. The winds tend to reduce the snow cover thereby allowing
moose easier travel to browse areas and also making more browse
available to the moose. The average temperatures in the Matanuska ··
Valley are considerably warmer than those of Area III. Area III lies
within a deep snow belt; frequently 40 or more inches of snow cover
the ground and consequently also cover the low shrubs, thereby reducing
the amount of available winter browse. Theoretically the more favorable
climate of Area I should allow for a greater survival of calv.es and for
better survival of the oldest age class individuals.. The harsh winters
of Area Ill could cause great mortality of calves and old animals.
The data obtained from the railroad killed moose indicate that the
two populations are possibly responding to the effects of climate as
illustrated in the preceding discussion. Area I has a very dense
population of moose, with a considerable number of old females. Area
III has considerably fewer moose per square mile but has an overall
younger population.
Other factors may be affecting the age structure of these populations.
The numbers of moose in Area III may be increasing, although there are
no data to indicate a substantial increase in moose numbers in this area.
Area I populations possibly are decreasing, hence an unbalanced old
population; however, the annual calf:cow ratios indicate that production
is excellent and last fall's hunting season revealed that survival of
bull calves to 16 months was very good.
-87-
Table No. 14. Sex and age ratios of three local moose populations
(as obtained from railroad kills the winters of 1955-56 and .1956-57).
Percent of Percent of
Age Males in Females in Percent
Classes Total Each Local Each Local of Total
& Area cf ·~ Sample cf:lOO ~ Population Population Sample
Fetuses 37 36 73 103
Calves 64 65 129 .98
Class I
150-17 5 2 1 3 200 40 5
176-200 2 2 4 100 10 3
20 l-250 9 6 .. 15 150 15 8
Combined 13 9 22 144 15 6 9
Class II & lii
150-175 2 3 5 66 40 12
176-200 5 7 12 71 23 12
201-250 11 18 29 61 18 25
Combined 18 28 46 64 21 18 19
Class IV & V
150-17 5 1 6 7 16 20 25
176-200 10 20 30 50 45 34
20 1-250' 23 20 43 115 38 28
Combined 34 46 80 74 39 30 33
Class VI & VII
150-175 0 8 8 0 0 33
176-200 4 18 22 22 18 31
201-250 12 19 31 63 20 27
Combined 16 45 61 35 18 29 25
Class VIII~ IX
150-175 0 6 6 0 0 25
176-200 1 11 12 9 5 19
201-250 5 8 13 62 8 11
Combined 6 25 31 24 7 16 13
Cotnb;ined II'otals
150-175 5 24 29 21
176-200 22 58 80 38
201-250 60 71 131 84
Total 87 153 240 57
-88-
Table No.15. Sex and age composition of Railbelt and Matanuska Valley
moose populations by age class (as obtained from railroad
killed moose~during the winters of 1955-56 and 1956-57).
Area and 1955-56 1956-57 . Combined
Age Class c! ~ c! ~ c! ·~ c!:lOO ~
150-175
I 1 1 1 0 2 1
II 0 0 0 1 0 1
III 1 2 1 0 2 2
IV 0 2 0 2 0 4
·v 1 1 0 1 1 2
VI 0 4 0 1 0 5
VII 0 2 0 1 0 3
VIII 0 1 0 0 0 1
IX 0 5 0 0 0 5
Totals· 3 18 2. 7 5 24 21
176-200
I 1 2 1 0 2 2
II 0 2 0 0 0 2
III 3 3 2 2 5 5
IV 3 8 3 3 6 11
v 3 6 1 3 4 9
VI 2 6 1 0 3 6
VII 0 8 1 4 1 12
VIII 1 4 0 1 1 5
IX 0 6 0 0 0 6
Totals 13 45 9 13 22 58 38
201-250
I 8 4 1 2 9 6
II 1 3 3 -3 4 6
III 4 4 3 8 7 12
IV 5 4 7 4 12 8
v 9 9 2 3 11 12
VI 6 10 5 1 11 11
VII 1 8 0 0 1 8
VIII 3 5 0 0 3 5
IX 2 2 0 1 2 3
Totals 39 49 21 22 60 71 84
-89-
Table No.I6. Age of 112 cow moose killed by trains the winter of
1955-56 between Mile Posts 150-250 on the Alaska
Railroad.
Age Class Number of Moose Percent of Total
I 7 6
II 5 5
III 9 8
IV 14 13
v 16 14
VI 20 18
VII 18 15
·VIII 10 9
IX 13 12
Total 112 100
-90-
Weights anq1vfeasurements
Peterson (1955) summarized the available weights and measure-
ments of the four subspecies of North American frioose. The Alaskan
subspecies, Alces alces gigas, is represented in his data by five
specimens (bulls collected for museum groups taken from the Kenai
Peninsula). No weights are recorded for the Alaskan specimens.
Eighty-three moose, of Age Class Calf or above, were weighed
or measured in conjunction with current moose management studies
of the Railbelt and Matanuska Valley moose populations in south
central Alaska (Table No.17)~
The weights are in pounds and' a.re· self explanatory.· The
measurements are in millimeters and definition is necessary. The
definitions are as follows:
Girth--This measurement was taken as a circumference of the
body back of the forelegs--around the deepes(part of the chest.
Hind Foot--This measurement was taken from the heel of the
calcaneum to the tip of the hoof.
Total Length--This measurement was taken from the tip of the
nose to the tip of the tail, excluding hair, following the body
contours.
Ear--This measurement was taken from the notch to the tip of
the ear, excluding hair.
Height at Shoulder--This measurement was taken from the
vertebral spine of the scapula to the bottom of the hoof.
Pelvis--This me.asur.ement was taken from the crest of the ilium
to the tuberosity of the ischium.
Body--This measurement was taken from the metacromium
process of the scapula to the atlas.
Neck--This measurement was taken from the metacromium
process of the scapula to the atlas.
Tail--This measurement was taken from the tip of the tail,
excluding hair, to the first sacral vertebra. On moose this
measurement is very difficult to take accurately.
-91-
Table No.l7. Weights and measurements of moose.
· Measurements i ' . Weights Z · Accession
Date Age Girth H. F. T. L. E. Ht. Sh. .Pelvis Body Neck' T.~ Body . Total Sex No.
5/29/57 Calf 655 445 1140 135 835 40 ~ 968
6/2/57 Calf 660 465 1090 140 795 220 600 240 45 48. cJ 969
6/5/57 Calf 600 42.0 880 125 770 175 500 40 31 ~ 970
6/6/57 Calf 630 440 1105 .140 850 .200 570 45 45 cJ 971
6/13/57 Calf 810 510 1190 160 960 245
.,\
680 270 60 78 ~ 501
6/15/57 Calf 610 444 842 130 864 39 ? 974
6/18/57 Calf 720 460 1180 140 850 210 58 cJ 973
6/18/57 Calf 680 430 1040 140 840 .. 19Q 53 ~ 972
. 6/24/57 Ca,lf 680
i
472 1052' 153 942 185 62 cJ 975
6/30/57 · Calf 489 1155 927 51 54 cJ 504
7/11/56 Calf 533 1295 171 114 102 cf n
7/18/57 76 ...0 Calf 552 1220 1092 110 .~ 507
N n.
(Kalgin ls.land Moose3
(
(6/18/57 ':~calf 680 430 i.040 140 840 190 53 ~ ~72
(6/30/57 ·~··· Calf 711 451 1079 863 ~ 972
(8/11/ 57 Calf 914 533 1549 1041 ~ 972
(
(6/18/57 Calf 720 460 1180 140 850 210 58 r:J 973
( 6/30/57 Calf 737 457 1117· 914 r:J 973
{8/11/57 Calf 990 558 1625 lll7 r:J 973
11/15-20/57 Calf .1499 673 2108 229 1397 .381 1321 267 425 ~ 944
11/23/57 Calf 673 . 1359 1066 210 310 c! 779
11/(.3/57 Calf 711 229 1499 270 r:J 820
12/20/56 Calf 285 450 r:J 340
Table No. 17 (Continued).
Measurements Weishts Accession
Date Age Girth g. F .. T~L. E. Ht. Sh. Pelvis Body Neck T; Body Total Sex No.
'
1/2/57 Calf 62.2 1626 1257 ~ 352
. 1/4/57 Calf 635
1/8/58 Calf 1321 660 1930 216 1435 394 991 108 210 325 (! 964
1/16/57 Calf 1575 610 1981 254 1422 381 1219 406 275 425 ~ 328
1/21/!58 Calf 162.·6 718 1981 22.2 1511 445 1422 470 265 425 d 984
1/?.6/57 Calf 635 205 c! 339
i321 ' 1/26/57 Calf 1473 635 1549 229 330 300 ~ 327
1'/26/57 Calf 1473 660 2024 ~ 334
1/26/58 Calf 1549 699 2007 210 1397 406 1321 394 385 ~ 987
1/7.9/58 Calf 1473 692 2'159 215 1505 413 1232 406 d 994
1/31/57 Calf 1524 711 203 223 d 418
2/3/58 Calf 1372 718 2184 222 .1397 419 1346 240 395 c!
n 2/4/57 Calf 1524 686 1549 22'5 375 d 375
...0 2/4/57 Calf 1422 686 1473 zjs c! 366 1./.l
v 2/4/57 calf 610 1473 205 '·. r,
~ 2.23. 4 1397
2/11/57 Calf 673 2os' ~ 2/11
i/13/57 Calf 1461 6S6 1880 216 1575 356 268 4;15 ~ 379
2/14/57 Calf 216 1448 240 ~ 389
. 2/16/57 Calf 1270 648 1575 191 1397 318 1092 368 140 230 ~ 380
2/23/57 Calf· 1524 660 1676 1461 318 205 310 ~ 397
2/26/57 Calf 1321 673 1930 216 1422 343 305 200 31'5 d 403 ..
3/2/57 Calf 1422 673 1803 216 1499 356 235 385 ~ 405
3/11/57 Calf 1321 660 1854 216 1372 356 195 295 c! 426
8/31/57 I 2159 241 1549 485 ~ 543
9/2/57 l 1981 749 243.8 254 1651 533 157.5. 495 6.30 ~ 536
3/19/57 I 1829 813 2642 254 1753 533 508 457 669 ~ 428
Table No. 17(Continued).
Meaaureme#ts Weights Accession
Date Age Girth. H.. F. T. L .. E ... . Ht~ Sh. Pelvis Body Neck T. Body t.otal Sex No. . ..
9/2/57 II BOO 1715 590 ' .,.
!? 513
10/31/57 II 2,134 813 2515 1880 !? 677
3/4/57 II 1930 762 2134 254 1803 540 770 ~ 415
8/24/57 II-III 749 248 1676 843 ·~ ~~9
11/26/57 III-IV 1880 775 254 1753 1524 406 690 840 ~ 8/2~/57 III-IV 1905 787 2591 248 1727 533 1727 584 102 545 840 ~ 528
1/8/57 IV-V 813 870 -~ 4.26
. 2/4/57 IV-V 1905 838 1854 665 ~ 373
2/1.3/57 IV-V 1905 787 2438 260 1880 508 610 540 828 ~ 378
4/9/57 rv-v 80'0 248 1829 sto 695 ~ 450
3/14/57 v 762 . 2489 254 1854 457 570 ~ 430
n 8/25/57 V-V.I 2032 800 2642 267 H~54 584 1753 . 559 706 995 ~ 521
1.0 9/2/57 VI 2337 787 2692 254 18D,3 508 925 ~ 531 ~
8 3/9/57 VI 1930 787 2337 241 1880 495 580 ~ 417
4/2/57 V.I 1880 787 2718 254 ~905 559 1753 584 514 800 -~ 448
9/16/57 VI-VII 2286 806 2845 273 1880 1702 660 670 955 ~ 586
6/9/57 VI-VII 1803 800 2692 241 1803 483 584 89 540 760 -~ 500
11/3/57 VIII-IX 2083 826 2616 1854 ~ 676
2/22/57 IX 762 500 ~ 398
4/10/57 IX 787 260 1727 411 579 ~ 451
12/19/57 Adult 2108 806 2794' 248 !j! Tags' 99-100
1/17/57 Unknown 762 908 ~ 344
8/21/57 I 775 2083 248 1536 1080 152 d 629
8/22/57 I 1727 737 2464 254 d 821
9/8/57 I 1524 762 1600 450 .cf 82-2.
. 2/7/57 I 749 1753 652 d 391
3/31/57 I 1626 800 2743 254 1753 1549 559 d 444
Table No. I7(Continued).
Measurements
Date Ase. earth H. F .. T .. ~. E. Ht •. Sh .. Pelvis
8/2.0/57 n 800 4642 .254 1638
12/18/57 lli 813 1778
2./4/57 lll
9/20/57 IV 82.6 2.819 267 1981
2/16/57 IV-V 813
1/31/57 VI 2.235 838 2134
2./1.4/57 Vl 826 2.54 2083
1/8/58 Vlll 22.61 838 2.870 2.54 1930
11/2/57 U:rikn. 1930 787 2.629 273 1880
2./7/57 Unkn. 1702 762. .1803
~ 1 Measurements in millimeters.
~ · Z Weights in pounds. ! These courtesy of Charles Parsons.
Starved. 5 With ~fitlers.
·Weights Accession
Body Neck T.· Body Total Sex ·No.
'
d 630
809 5 d ~38
545 d 369
. 12.7 d 587
580 d 402
780 1085 .d 360
730 d 387
. 1778 559 870 1140 d 965
540 d 790
460 645 d . 208.5
Although the present data are too few to be conclusive, it seems
that very few mature bulls exceed 12,00-1400 pounds in total weight
even in their pre-rut prime. Total weights of four bulls, and hog
dressed weights of six bulls, Age Class I and above are presently
available (Table No. 17). The weights of the mature bulls, Age
Class III and above, are all from the winter months, a period when
bulls are very thin and possibly weigh 10 to 15 percent less than.
during their pre-rut prime in the early fall (Skuncke 1949). The
heaviest of these individuals weighed a total of 1140 pounds. Skeletal
measurements indicated that this was a very large moose.
The maximum total weight of 17 females Age Class I and above
was 995 pounds. The average total weight of 10 females Age Class II
and above which were collected during the fall and winter months was
877 pounds. Cow moose do not lose weight during the breeding season
in late September and early October and consequently they enter the
winter in prime condition. They do, however, utilize their fat
deposits gradually during the winter and by spring have lost consider-
. able weight. The average total weight of four females above Age
Class II which were collected in late spring and early summer,. was
708 pounds; roughly 20 percent less than the average of the 10
individuals collected during the fall and winter. The amount of
weight lost by individual female moose is dependent upon a number
of factors including the severity of the winter and the quantity and
quality of available winter browse. The few weights recorded here
are not necessarily typical of all areas. Certainly, a greater number
of individuals representing all seasonal perio¢ls and contrasting
climatological and range conditions are needed before conclusions
are drawn concerning average winter weight losses.
Growth
Moose calves grow rapidly during their first five or s~x months
of life and may weigh 10 or more times their birth weight by the end
of this period. Calves, which inthis area are born from mid-May
to early June, weigh approximately 25 to 35 pounds at birth
(Kellum 1941; Skuncke 1949) and by mid-November they may weigh
. as much as 400-450 pounds.
The average of 10 calves weighed during late May and June (nine
were weighed in June) was 50 pounds; two calves weighed in mid-July
averaged slightly over 100 pounds apiece; three calves weighed in
mid-November averaged, 385 pounds apiece.
=96=
The growth of moose from conception through the first year of
life is illustrated in Figure No. 10. This graph was constructed
from the total length measurements of 95 moose embryos, fetuses,
and calves. In this and in the subsequent figures in this section of
the report the individual measurements are represented by a point
and the averages for the indicated periods by a circle. The curve
was fitted to the averages by visual inspection. This is a
generalized and tentative curve, as are those given in subsequent
figures, and it is not meant to represent any biologica1law of
growth, nor to picture detailed variations in the growth pattern.
The range of total lengths is quite great, particularly in those
taken during the winter months when the moose were 6-10 months
old. This may well reflect individual differences in rate of growth.
The rate of individual growth may be affected by a number of factors
of which the more obvious are; differences in the rate of development
between the sexes, between twins-and singletons, individual
differ.ences, i.e. , genetic, and variations in local environmental
conditions. At present data illustrating these factors are very
meager. Skuncke {op. cit.) reports that males exceed females in
total growth at the end of six months. There is some indication that
moose vary in size from one area of Alaska to another. Again,
weights and measurements representing the various areas are too
few to be significant.
Growth from the early fetal stages through the first five or six
months of life is continuous although at a progressively decreasing
rate. With the onset of winter conditions in late November, growth
apparently halts.
The growth of moose from birth through approximately 22 months
is illustrated in Figure Nos. 11 and 12.. Figure No. 11 is based upon
total weights of 40 moose. The curve was fitted to these averages
by visual inspection. Figure No. 12 represents hind foot measurements
of 49 moose. This curve was fitted to the biweekly averages by
visual inspection.
The data represented by Figure Nos. 11 and 12 indicate that moose
calves grow only during the summer and early fall. Apparently their
winter forage, largely willow, birch, and aspen twigs, provides only a
maintenance diet. It has been demonstrated that many grasses, legumes,
and some trees lose much of their food value at maturity. This,
combined with the change from a lush summer diet of leaves,
shrubs, and aquatic vegetation and milk, plus the increased difficulty
of obtaining food with the advent of snow, perhaps, causes a cessation
of growth. However, the physiological processes responsible for the
-97-
cessation of growth and the stimuli governing them are not, at
present, completely understood. This writer believes that in moose,
one of the principal factors is the low nutritional plane of the winter
diet.
Another period of relatively rapid growth commences in the
spring of the moose's second year and by September or October,
at 16 to 17 months of age, approximately 90 percent of the total
skeletal growth is completed. It is interesting to note in Figure No. 13
that the second period of growth appa.rently ends in September or
October, concurrent with the rut, whereas calves probably grow
until November.
Total weight, however, continues to increase for a number of
years but apparently at a much reduced rate. Skuncke (op. cit.)
indicates that in Sweden moose grow in total weight, until at least
seten years of age and that bulls probably grow in total weight
until ten years of age. He further states that females do not grow
much after the first three or four years. The weights and
measurements of the Alaskan subspecies listed in Table No.l7 and
illustrated in Figure No.l3 indicate that females grow very little
in either total weight or skeletal measurements beyond Age Class III.
-98-
I -.o -.o
I
Figure No.lO, Growth. of moose from conception to 10 months post partum as illustrated by
total length measurements of 95 embryo.s, .fetuses, and calves.
2400 m
2100
1800
1500
1200
900
600
300
.
+" ()
0
• • •
• ••
•
• • ••
•
•
0 .....
0
0
0
Figure No.11. Growth of moose from 1 to 22 months as illustrated by total weights of
40 individuals.
600
500
400
300
200
100
I ' /
I
I
I
I
/
I
I
I
/
0--.-..... /
I ~ .... -I
> 0 z
.
(.)
(!,)
~
-e--
,.c
(!,)
r.x.
/
/
/
/
/
/
I
~--
1
-----.....@
> 0
~
.
(.)
(!,)
~
. ,.c
(!,)
r.x.
.......
0
Figure No.l2. Growth of moose from 1 to 22 months as illustrated by hind foot measurements
of 44 individuals.
800 mm__
750
700
650
I
I
I
I
·.· / . / . . / 0 • • , : ;"' - - --..-o--. - - -_,
./ .~ . .
/ \:I .-·
••• •
/
• •
. ,--------o
/.
,;~>. •
/ .
~ 600 I
I
• •
550
500
450
I
·' . a' 07 • I .
•
I ,.
I
I
I
. ... u
0
> 0 z t:
0
> 0 z
. u
a.>
~
.
,.Q
a.>
~
.
J.t
~
I ....
0
N
I
Figure No.l3. Growth of moose from birth to maturity as illustrated by total weight.
(Beyond Age Class II only weights of females are shown)
1050
900
750
600
450
300
150
nds
,--
1
I
I
I
I
I
I
•...._ I I .... ,~
I
I
I
I
I
I
I
I
T
I ..
-/
/
/
'/
/
/
. ,.-,,.
"
•
• •
• ,_'A----IJ---. --------- -
•
•
• • •
Age Class Calf I II III IV v VI VII VIII
•
•
IX
Notes on the Incidence of Echinococcus granulosus in Moose
One hundred and twenty-four sets of moose lungs have been
collected and examined for the presence of hydatid cysts,
Echinococcus granulosus larvae. The lungs were collected in
conjunction with studies of the moose-railroad conflict, checking
station operations, and routine examination of highway and other
accidental kills. The collection of these data was greatly facilitated
by cooperation of the management of the Alaska Railroad, railroad
section personnel of the Willow, Caswell, Sunshine and Talkeetna
sections, and local Fish and Wildlife Service game management
agents.
The presence or absence of the tapeworm cyst was determined
by visual inspection, palpation, and finally by sectioning the lungs
into slices approximately one-half inch thick. Hydatid larvae do not
always localize in the lungs of the hos:t, but examination of 86 moose
livers and hearts, the lungs of which were also checked and 17 were
infected, have given negative results.
The life cycle of this par<i,site has been reviewed by R. L. Rausch
( 1952). The cycle usually involv;es ungulates as the intermediate
host, and canines as the final host .. The larval form, the hydatid
cyst, is found in the intermediate host; usually moose and caribou in
this portion of Alaska. The adult tapeworm is found in the final host,
in Alaska, usually wolves or dogs. Coyotes are possible final hosts,
although according to R. L. Rausch (viva voce) no instances of
Echinococcus infected coyotes from the study area are known.
In compiling the data a natural geographic feature was used to
separate the two areas portrayed in Figure No.I4 and the data
tabulated in Table Nos.l8 and 19. All moose collected north of Knik
Arm were considered in the Railbeit-Matanuska Valley populations
and all moose south of Knik Arm are considered in the Anchorage-
Upper Kenai populations. In all probability there is very little, if
any, interchange between these two areas as Knik Arm and the
adjoining mountains constitute a formidable natural barrier.
Analysis of these data reveal interesting information relative to
the incidence, distribution and possible final hosts in the Lower
Susitna Valley and Anchorage areas.
The incidence of E. granulosus in a moose population seems
dependent upon the availability of the parasite and the length of time
the individual host species has been exposed to it, i.e., the age of
-103-
Figure No. 14. The Railbelt-Matanuska Valley moose populations (Area I)
and the Anchorage--: Upper Kenai moose populations (Area II) . ..
Mt. YeiJ.lo
401~/"
II It
'/1 "\ \
88,49
7270 8000
AREA I
7530
9646
7425
AREA II
-104-
Table No.l8. -Incidence of-Echinococcus granulosus in the
Railbelt Moose Populations.
Percent Percent
Age Groups No. Lungs No. Infected Infected of Sample
Calf 23 0 0 22.8
I 13 2 15.3 12.8
II & III 13 2 15.3 . J 2. 8
I, II & III 26 4 15.3 25.8
IV, V & VI 29 8 27.5 28.7
VII,· VIII & IX 16 10 62.5 15.8
Unknown 7 2 28.5 6.9
·Totals 101 24 23.7 100.
Excluding Calves 78 24 30.7
Table No.l9. Incidence of Echinococcus granulosus in the
Anchorage-Upper Kenai Moose Populations
Percent Percent
Age Groups No. Lungs No. Infected Infected of Sample
Calf 3 0 0 13.
I 3 0 0 13. 1
II & III 4 0 0 17.4
I, II & III 7 0 0 30.5
IV, V & VI 5 1 20 21. 7
VII, VIII & IX 8 0 0 -34.8
Totals 23 1 4 100.
Excluding Calves 20 1 5
-105-
the individual. In the Railbelt-Matanuska Valley populations the
incidence of hydatid disease ranges from 15 percent in the age
category composed of Age Classes I, II and III (1, 2, 3, and possibly
some 4 year old individuals} to 63 percent in the age category
composed of Age Class VII, VIII.and IX individuals. The latter
probably includes moose from 7 1/2 to 20 years of age (Skuncke 1949).
Hydatid cysts were not found in calves of the year. Excluding calves,
24 or 30.7 percent of 78 individuals examined were infected.
E. granulosus is not common in moose populations located in the
areas south of the Knik Arm. Only one instance of infection was
observed in the 23 sets of lungs examined by this writer.
The reasons for the differential rate of infection between the two
areas are not fully understood at present. Possibly, the final host
is not present in the Anchorage-Upper Kenai areas or if present, is
not sufficiently abundant to insure infection of the ungulate group.
In fact, the final host group is not definitely known for either study
area. Wolves are absent or very rare in both areas, coyotes are
present in both areas but are not abundant and the mature tapeworm
has not been identified from a coyote. Dogs are very numerous in
both. areas and are allowed to roam freely by most owners. Again
quantitative evidence on the incidence of E. granulosus in dogs of
these areas is not available. In view of their abundance and
distribution dogs seem the logical final hosts. in the study areas.
Several authorities have discussed the possible pathogenic
effects of hydatid disease on the ungulate host (Cowan, 1944, and
R. L. Rausch, 1952).
During this study the general physical condition of each animal '·.
examined was recorded and the incidence of pregnancy was also
noted. In no instance was the physical condition of infected animals
visibly different from noninfected animals and the pregnancy rates
of infected and noninfected animals were identical; 90 percent of all
females Age Class II and above were pregnant. At present, this
writer has observed no instances where hydatid disease appeared,
upon gross examination, to be significantly detrimental to the vitality
of the ungulate host.
-106-
..
•
RECOMMENDATIONS
1. The r.p.oose kill reporting system and collection of moose heads
should be continued. The reporting and collecting should continue
throughout the year, not just during the winter period .
2. Daylight train operation and slow orders in critical kill areas
should be implemented whenever economically feasible. Aerial counts
made of the moose inhabiting the area along the right-of-way reveal
these critical and potentially critical areas.
3. Trails and feed yards should be constructed in areas with
histories of critical kill.
4. Moose guards warrant further testing.
5. The study of seasonal moose movements should be continued.
6. This project has defined the current moose problem and yielded
several temporary moose saving expedients. Continued study, on a
cooperative basis, should provide further understanding ofseasonal
moose movements and the feasibility of altering them to the benefit of
the railroad and the moose.
7. Collection of biological data relative to the reproduction, health
and age of the study populations should be continued.
LITERATURE CITED
Armstrong, R. A. 1950. Fetal development of the Northern White-Tailed
Deer (Odocoileus virginianus borealis Miller). The American
Midland Naturalist, 43(3) :650-666.
Chatelain, E. F. 1951. Winter range problems of moose in the Susitna
Valley. Proceedings Alaska Science Conference, 2:343-347.
1952. Distribution and abundance of moose in Alaska.
Proceedings Alaska Science Conference, 3:134-136.
Cheatum, E. L. 1946. Breeding season of White-Tailed Deer in New
York. Journal of Wildlife Management, 10(3) :249-263.
1949. The use of corpora lutea for determining
ovulation incidence and variations in fertility of the White-Tailed
Deer. Cornell Veterinarian, 39(3):282-291.
-107-
Galley, :f. B. 1957. An appraisal of ovarian analyses in determining
reproductive performance of Black-Tailed Deer. Journal of
Wildlife Management, 21( 1) :62-65.
Kellum, F. 1941. Cusino' s captive moose. Michigan Conservation,
Michigan Department of Conservation, 10(7) :4-5.
Lensink, C. J. 1955. Tentative method for aging moose. Federal
Aid in Wildlife Restoration, 10(2).
Lonnburg, Einar. 1923.
Gok, Albert Bonnier.
Sveriges Jaktbara Djur. Svenska Jordbrakets
Stockholm, Haft. 1, pp. 1-65.
Peterson, R. L. 1955. North American Moose. University of Toronto
Press, Toronto, Canada, pp. 1-" ~80.
Quimby, D. C. and J. E. Gaub. 1957.
indicator in Rocky Mountain Elk.
21(4)~435-450.
Mandibular dentition as an age
Journal of Wildlife Management,
Rausch, R. L. 1952. Hydatid disease in Boreal regions. Journal of
the Arctic Institute of North America, 5(3)~157-174.
Ritcey, R. W. and R. Y. Edwards. 1957. Letter of June 19 to
Robert F. Scott.
Robinette, L. W., J. S. Gashwiler, J. B. Low, and D. A. Jones.
1957. Differential mortality by sex and age among mule deer.
Journal of Wildlife Management, 21( 1) :1-16.
Skuncke, F. 1949. Algen, studier, jakt och vEl.rd. P. A. Norstedt
and Soners,. Forlag, Stockholm, pp. 1-400.
Winters, L. M. and G. Feuffel. 1936. Studies on the physiology of
reproduction in the sheep. University of Minnesota Agricultural
Experiment Station Technical Bulletin 118, 20 pp.
,_ W. W. Green, and R. E. Comstock. 1942. Prenatal -----------------development of the bovine. University of Minnesota Agricultural
Experiment. Station Technical Bulletin 151, 44 pp.
-108-
VIVA VOCE REFERENCES
Buckley, J. L. 1957. Leader, Cooperative Wildlife Research Unit,
College, Alaska.
Rausch, R. L. 1958. Chief, ZoonoticDisease Section, Arctic Health
Research Center, United States Public Health Service, Anchorage,
Alaska.
Watson, G. W. 1957. Fish and Wildlife Administrator, Branch.of
River Basins Studies, Fish and Wildlife Service, Anchorage, Alaska.
Prepared by: Approved by:
Robert A. Rausch Robert F. Scott
Wildlife Management Biologist Supervisor of Game Restoration
Date: January 31, 1958
----------~--~--~-----
-109-
JOB NO~ 5: Food Habits of Railbelt Moose
PERIOD COVERED: January 1, 1957, to March 31, 1957
ABSTRACT
Rumen content samples from 122 moose killed by trains between
Mile Posts 172 and 231 on the Alaska Railroad during the winters of
1955-56 and 1956-57 were analyzed. Only the gross particles, an
average of 5 percent of each sample, were considered. This analysis
revealed the following: ( 1) seventeen food items were identified;
(2) willow, birch and aspen comprised 97 percent of the identifiable
food material; (3) moose ate more willow during 1956-57, possibly
due to lesser snow accumulations; and ( 4) until some technique for
identifying the small food particles, which comprise about 95 percent
of an average rumen content sample, is devised the validity of the
present technique is questionable.
OBJECTIVES
To determine relative occurrence of the various browse species
in samples of moose stomach contents taken along the railbelt.
TECHNIQUES USED
Research investigations began with a review of available literature
concerning stomach content analysis of browsing animals. Few entirely
satisfactory methods were discovered and conspicuous among the
methods reviewed was the absence of a technique for evaluating the
proportion of food items which are unidentifiable with the unaided eye.
Probably Dusi ( 1946) has come closest to devising a workable
microtechnique for food habits studies. This technique involves the
use of plant tissue slides and photographs for comparison with fecal
pellet. Therefore, when the stomach sample investigations began,
an attempt was made to develop a similar technique.
In order to properly prepare the plant tis sues for slide mounting
they were first fixed, then macerated in a solution of chromic acid
and nitric acid as described by Dusi (op .. cit.). Following the maceration
process, the plant material was centrifuged in distilled water until
clear and acid free. Next, the various plant tissue samples were
placed in a solution of Mayer's Haemalum for approximately fiVEf to
ten minutes. The Haemalum stain was not too successful, but
examination of prepared slides showed some distinct cell detail which
-110-
was encouraging, in that generic separation appeared possible.
Further experimentation with one percent aqueous safranine proved
worthwhile as slides prepared with this dye were clearer and showed
more detail than the previous stain. Before mounting on slides the
stained tissues were dehydrated with Tertiary Butyl alcohol. Canada
Balsam mixed with Tertiary Butyl alcohol was used as a mounting
medium.
Permanent slides of. reference plants were made with which
stomach samples or pellets were to be compared. Considerable
difficulty was encountered in differentiating plant cells of the two
genera in the willow family. Separation of these genera was thought
possible by fiber length, but statistical analysis of the various fibers
showed too great an overlap to use this measurement criteria for
identification. Some attention was given to the organization of slope
of pits on the plant vessel walls, but again this criterion was not
distinct enough in any of the closely related plants to assure positive
identification. Thus, since use of the proposed technique could only
be realized through extended research, which at the time was not
feasible, only the particles identifiable macroscopically were used.
The identification of the gross particles was accomplished (in the
case of the dry samples, 1955~56) through hydration of the samples
by boiling until the stoma.ch contents had reached. a saturation point.
The next step was to wash the material through a wire mesh. screen.
A one-quarter inch mesh screen was found to be the most satisfactory
for retaining identifiable food iteJhs. These remaining coarse
constituents were examined with the unaided eye or a 6X binocular
microscope.
Identifiable materials were segregated by species and measured
volumetrically by the water displacement method. This was
accomplished by removing the food items from the containers in which
they were segregated and placing them on absorbent paper towels to
dry, then transferring them to a graduated cylinder. Readings of the
identifiable material were taken to the nearest . 1 milliliter. All otre r
materials were measured to the nearest milliliter. With the exception
of hydration, the frozen samples (1956-57) were subjected to the same
process as the dry preserved samples.
During the course of the investigations several problems arose,
presenting obstacles still needing resolution. Perhaps the greatest
problem encountered in analysis of the stomach samples was the
condition of the samples. The first series (1955-56} was dried and
hydration by boiling was necessary in order to restore the food items
-111-
into more readily recognized particles. This condition was not
encountered in the 1956-57 group, as these samples were preserved
by freezing. Consequently, plant tissues from this group were
identified more accurately and with greater ease.
In addition to being thoroughly dried, some samples in the
1955-56 series had been subjected to considerable damage by wood
and bark eating insects. Identification of heavily damaged samples
was only possible by microscopic examination; fortunately, only
14 out of 73 samples needed this treatment. If possible, samples
should be preserved in formaldehyde o:r frozen if proper storage
facilities are available.
Another problem, although not as acute, was the lack of a complete
reference collection of moose browse items. However, this lack was
met by compa~ing food items with herbarium specimens at the University
of Alaska. For future analysis work, a collection of known food items
should be gathered and identified.
When the reference plants were subjected to acid treatments
there appeared to be a differential breakdown of tissues. In the same
sense these tissues appear to break down similarly in moose digestive
juices; that is, birch appeared to be the hardiest while willow, and
especially aspen, tended to be less resistant to mechanical and chemical
actions. Consequently, the effects of such factors might introduce a
bias in analyses based on only the readily identifiable food particles.
FINDINGS
This report presents the results of an analysis of 12.2 moose rumen
content samples collected along the Alaska Railroad during the winters
of 1955-56 and 1956-57. The samples were collected by Robert A. Rausch,
Dustin L. Sloan and railroad employees, between Mile Posts 172 and
231 on the Alaska Railroad.
Seventeen different food items were identified from the 122 samples
analyzed. These food items included, in order of total identifiable
volume, the species as follows~ willow (Salix spp.). birch (Betula spp. ).
aspen and cottonwood (Populus spp. ).!/, high-bush cranberry (Vibur~
~), alder (Alnus sp.), grasses (Graminae), Labrador tea (Ledum spp.),
hemlock or water parsnip (Umbelleriferae), spruce (Picea spp. ),
bog blueberry (Vaccinium uliginosum), moss (unknown), red alderberry
{Sambucus racemosa), low-bush cranberry {Vaccinium vitis-idaea),
fungi (unknown), currant (Ribes ~). horsetail {Equisetum S..E£:.,).
!:.._/ ·The term aspen as used in this report refers to all species of
Populus that occur in the railbelt area.
-112-
dwarf dogwood ( Cornus sp.), wild rose (Rosa acicularis).
The three most important browse species, willow, birch and
aspen, comprised about 97 percent of the total identifiable volume for
both years' samples. The average percentage occurrence of willow,
birch and aspen in 1955~56 was 49, 37 and 10 percent, respectively
(Table No. 1). In 1956-57 the average percentage of occurrence for
the same species was 65, 24 and 8 percent, respectively (Table No. 2).
The average percent occurrence for the three important species in .
1955-56 and 1956-57 are very similar to the findings of Spengz.er (1953)_
which were based on the analysis of 96 moose stomach content samples
collected from railroad killed moose between Mile Posts 172 and 228
on the Alaska Railroad. The average percentage occurrence in
Spencer's _. samples were as follows: willow, 53 percent; birch,
37 percent; and aspen, 12 percent.
The utilization of willow and birch differs considerably between
the winters of 1955-56 and 1956-57 whereas consumption of aspen and
browse species of lesser importance remained relatively constant.
Apparently, moose ate more willow during the winter of 1956-57.
Snow cover was the major variable between the two years. In 1955-56
snow cover was considerably greater than in the following winter.
Frequently 60 or more inches of snow covered the g~ound during the
winter of 1955-56, whereas 30 to 40 inches was about the maximum
accumulation of snow during the following winter. Snow cover affects
browse utilization in several ways. Deep snow materially restricts
travel by moose (thereby forcing them to remain in one area until all
browse is exhausted), covers low shrubs, and permits moose to utilize
browse that they would not be able to reach during winters of normal
snowfall.
The relative importance of the effects of deep snow is not known;
perhaps the most important single factor is the restriction of the
moose's mobility. Previous browse studies indicate that moose prefer
willow (Spencer 1953, Rausch 1956), but when climatological conditions
restrict the amount of favored species available to them, moose exist
on browse that would be eaten in lesser quantities under more favorable
conditions. The relative amounts of each potential browse species
available, as revealed by a browse reconnaissance of the study area
in 19 55-56, are illustrated by percent of total in Figure 1. The relative
utilization as revealed by analysis of the rumen content of samples
collected in 1955-56 and 1956-57 are also illustrated in Figure 1.
Willow comprised about 30 percent of the woody vegetation above
snowline but constituted about 60 percent of identifiable food in the
rumen content samples.
-113-
Table No. 1. Average 'species composition of moose stomach samples
collected--winter of 1955-56.
Average* Percentage
Species Percent .Range Frequency
Willow 49.2 0-100 96.2
Birch 37.1 •. 0-100 94.9
Aspen 10.7 0-100 50.0
Alder 1.8 0-28 11. 5
Currant Tr. ** 0-6 10.0
Elder Tr. 0-6 5. 1
Spruce Tr. 0-36 2.5
Horsetail Tr. 0-Tr. 1.3
Moss Tr. 0-17 1.3 * of identifiable material.
** Tr. ~less than . 5 of 1 percent.
Table No. 2. Average species composition of moose stomach samples
collected--winter of 1956--57.
Average*
Species Percent
Willow
Birch
Aspen
High Bush Cranberry
Alder
Labrador Tea
Low Bush Cranberry
Elder
Currant
Dogwood
-Wild Rose
65
.24
8
1 1-
1 -
Tr. **
Tr.
Tr.
Tr.
Tr.
Tr.
Spruce Tr.
Grass Tr.
Fungus Tr.
Water Parsnip Tr.
Bog Blueberry Tr.
* of identifiable material.
** Tr. : less than . 5 of 1 percent.
-114-
Percentage
Range Frequency
30-95 100
4-70 100
0-42 44.8
0-32 20.4
0-13 14. 2
0-16 10. 2
0-3 8. 1
0-3 4.0
0-10 2
0-Tr. 2
0-6 2
0-Tr. 2
0-Tr. 2
0-3 2
0-Tr. 2
0-8 2
Figure No. 1. Comparison of available browse and stomach contents
sample analysis.
80 ercent
40
w B
80 ercent
40
.w B
80 ercent
40
w B
19 55-56 Browse Composition Survey
Mile Posts 172-231, The Alaska Railroad
A Al s
1955-56 Stomach Sample Contents Analysis
A Al AO
1956-57 Stomach Sample Contents Analysis
-115-
W ---Willow
B ---Birch
A ---Aspen
Al---Alder
H. B.--High Bush
Cranberry
AO ---All Others
Although the results of this study are in general agreement with
other similar studies of moose browse utilization and do not differ
markedly from field observations on browse utilization, a system for
identifying a greater portion of each sample, to determine the validity
of the present technique, is needed, An average of about 5 percent
of each of the 122 samples was~ identifiable. The problems of
devising a technique for identifying the small food particles, roughly
95 percent of each sample, were discussed in the section on Techniques
Used.
RECOMMENDATIONS
A method for analyzing a greater percent of an average sample
should be devised.
LITERATURE CITED
Dusi, Julian L. 1946. A method for the determination of the food
habits of the cottontail rabbit by use of the plant microtechniqU:es
and fecal pellet analysis. M.S. Thesis, Ohio State University.
Rausch, Robert A. 1956. Mobse management studies. Quarterly
Progress Report, Federal Aid in Wildlife Restoration,
11{2) :l-43.
Spencer, D. L. andE. F. Chatelain. 1953. Progressinthe
management of the moose of South Central Alaska. Transactions
North American Wildlife Conference, 18.:539-552.
Prepared by:
Peter E. K. Shepherd
Biological Aid
Date: January 31, 1958
Approved by:
Robert F. Scott
Supervisor of Game Restoration
-116-
JOB NO. 5: Sampling of Kill by Hunters
PERIOD COVERED: August 20, 1957, to December 31, 1957
ABSTRACT
The 1957 moose hunting season can be summarized as follows:
1. Twelve percent of 2, 075 hunters checked were successful.
2. Two hundred ninety-five moose were checked; interviews with
guides and outfitters revealed 300 additional hunter kills for
a total known kill of approximately 600.
3. . Fifty-five percent of the moose checked were yearlings.
4. Ninety percent of the moose checked in the Matanuska Valley
were yearlings.
5. Yearlings, due to habitat preference, may be more susceptible
to hunters.
OBJECTIVES
To obtain data relative to the magnitude and composition of the
kill by hunters and to collect biological specimens and data.
TECHNIQUES USED
Data on the moose kill in south central Alaska, excluding the Kenai
Peninsula, were obtained from hunter checking stations, game manage-
ment agents' reports, and interviews with guides and outfitters. Two
hunter checking stations were operated, one on the Glenn Highway at
Palmer and the other on the Denali Highway near Paxson.
FINDINGS
During the 1957 hunting season 295 moose were checked at hunter
checking stations or by Fish and Wildlife Service field personnel.
Breakdown by checking agency reveals the following totals: ( 1) Palmer
checking station, 190 moose; (2) Denali checking station, 59 moose;
and (3) field pe-rsonnel, 46 moose.
-117-
·The number of moose hunters, length of average hunting trip, and
~ercent of successful hunters are summarized in Table No. 1.
Table No. 1. Summary of checking station data--19 57.
Station
Denali
8/20-9/4 Moose 980 2336 2.4 59 6 59 39.6
Palmer*
8/20-9/4 Moose 1095 2737 2.5 190 17 190 14.4
Total 2075 5173 2.4 249 12 249' 20.7
*Operated on weekends throughout season.
Moose hunting .during August and early September apparently was
most successful in the Matanuska Valley and along the Glenn Highway
where 17 percent of the hunters were successful; only six percent of
those hunting on the Denali highway were successful. However,
reports from guides and hunters indicate greatly increased hunter
success in the Denali: area during the last ten days of the first season.·
Additional information on the hunter take in the Lake Louise and Denali
Highway area was obtained from interviews with guides and outfitters.
The interviews, conducted by R. 0. Skoog. revealed that approximately
150 moose were taken from each of the former areas.
The total known kill is approximately 600 moose; however, a few
of the moose reported by the guides and outfitters undoubtedly were
checked at hunter checking stations. The distribution of the known
kill is as follows: Denali Highway, 200 moose; Lake Louise area, 150;
Glenn Highway system, 130; and the Matanuska Valley, 120.
Although the present data does not provide a means for accurately
estimating the total hunter kill. this writer believes that the 600 known
kills does not exceed 50 percent of the total hunter kill.
Age Composition of Hunter Killed Moose
Age data from 142 hunter killed moose were obtained. The age
compositions for the various areas are represented in Tables 2 and 3.
~118~
Table No. 2. Age class of hunter killed moose {by percent).
-.
Age Class Total
Area I II III IV v VI VII. VIII IX Moose
Matanuska Valley 87.5 7 4. 1 1.4 72
Willow 53· 13.5 6.7 6.7 6.7 6.7 6.7 15
Matanuska Valley-
Willow Combined 82 8 4.5 2.2 1.1 1.1 1.1 87
Glenn Highway 57 24 9.6 4.7 0 4.7 21
Denali Highway 17 22 28 17 11 5 18
Other Areas 25 25 25 6.5 12 6.5 16
Total All Areas 63.3 14. 1 10. 5 5 3. 5 1.5 2. 1 142
Total All Areas
Except Matanuska
Valley 38 21. 1 18. 3 8.4 7 3 4.2 --71
Table No. 3. Ratio of yearling bulls per 100 older bulls.
Yearling Bulls:
Area 100 Older Bulls Total Animals
Matanuska Valley 630 73
Willow 88 17
Matanuska Valley-Willow
Combined 373 90
Glenn Highway 50 36
All other Areas 31 17
Total All Areas 125 162
Total All Areas Except
Matanuska Valley 43 90
-119-
The sample of hunter kills obtained at hunter checking stations
represents the take by roadside and ground vehicle hunters. Very few
airplane hunter killed moose are checked. The age composition
data reveals that continued heavy hunting pressure greatly affects the
age composition of the bull population segment. In the Matanuska
Valley approximately 90 percent of the h,unter killed bulls were
yearlings (Table No. 2). The ratio of yearling bulls per 100 older
bulls also reflects the effects of hunting pressure, but in areas where
intense hunting is relatively recent this ratio indicates that yearling
males possibly are more susceptible to hunters (Table No. 3). Yearling
males tend to remain at low elevations· during the fall whereas many of
the older males are usually at or near timberline. This differential
habitat preference may cause an over representation of yearlings in
the hunter take.
Biological specimens collected at hunter checking stations are
reported on in other sections of this report.
RECOMMENDATIONS
A system of sampling that provides a basis for estimating the
annual hunter harvest of moose should be continued.
Prepared by: Approved by:
Robert A. Rausch . Robert F. Scott
Wildlife Management Biologist Supervisor of Game Restoration
Date: January 31, 1958
-120-
Job No. 6 --Herd Composition in Interior Alaska
PERIOD COVERED: October 31, 1957 to December 1, 1957
ABSTRACT
Aerial compositiqn counts were made in three specific areas subject
to hunting: the Tanana Valley, Fortymile, and the lower KoyukUk Valley.
Six hundred nine moose were counted in 19.8 hours for an average of 30.7
moose sighted per hour. The sex and age data are summarized as follows:
Tanana Valley: The calf:cow ratio decreased from 47:100 in 1956
to 42:100 in 1957· Survival of bull calves to yearlings indicated 35
per cent mortality. ·The bull:cow ratio of 68:100 indicated light hunting
pressure.
Fortymile: The calf cow: ratio decreased from 53:100 in 1956 to
46:100 in 1957· Survival of bull calves to yearlings indicated 20 per
cent mortality. The bull:cow ratio of 91:100 indicates light hunting
pressU.Z.e; however, it is believed that· a disproportionate sampling of
bulls may have occurred.
Koyukuk: The calf:cow ratio was 67:100 indicating a high level
of productivity. Data from 1956 were not available to determine calf
surv~val. The young bull:bull calf ratio of 48:100, however, suggested
higher mortality than in other areas; perhaps due to heavy wolf pre-
dation the previous yinter. The bull:cow ratio of 80:100 indicated
light hunting pressure.
-The calf percentage of the total herd continues at 20 and 19 per
cent for the Tanana Valley and:Eb~rtymile respectively. These ratios
have not changed since 1954. In the Koyukuk, there were 28 per cent
calves in 1957 as compared to 36 per cent in 1954.
It is apparent that the moose populations in the Tanana and
Fortymile are relatively stable and are:··n.ot· being affected adversely
by the present hunting pressure. The Koyukuk-moose herd also appears
to be in healthy condition despite unusually heavy wolf predation
during the_winter of 1957·
The data for this study are in the Federal Aid files of the Fish
and Wildlife Service at Fairbanks.
~121-
B
.......
N
N
B
,
I
I
I
I
Huslia
\\
'
Hughes
r
I
t
~
Figure 3. General Area Covered by Moose Surveys
Koyukuk River
boundary 'of survey area
Scale 1" = 16 miles
,,
Figure 2. General Area Covered by Moose Surveys
•, Fortymile
~----bounary of survey area
Scale 1" = 16 miles
I ....
N
~
I
Figure 1. General Area Covered by
Moose Surveys
Tanana Valley
N
6
-----boundary of su~e;v area
Scale · 1" = 16 miles
I
I
Tanana
River
(
I
\
' ' \
I
\
I
I
,,~ \ ,... . '-...."'-.'I t' __ ,
... I
I'
f
/
OBJECTIVES
To determine age and sex composition of local moose populations
as an index to productivity and survival in areas subject to signifi-
cant hunting pressure or wolf predation.
TECHNIQUES USED
During the period from October 31 to December 1, 1957, aerial
com:fjosition counts were conducted in the Tanana River and tributary
valleys near Fairbanks, the Mosquito Fork, Ketchumstuk Flats area of
the Fortymile, and the Koyukuk flats between Koyukuk Station and Hughes o
Counts were made using a Super-cub in the Tanana area, a Cessna 180 and
a Pacer in the Koyukuk area, and a Pacer in the Fortymile area. Flights
were made at elevations of 500-700 feet above the g~~und and moose were
tallied in the folloWing categories~
1. Small bulls -spiked, forked or antlers with very small palms
considered to be 18 months of age . There is probably some overlap be-
tween this class.and adults.
2 . Adult bulls -antlers medium to large o
3. Cows -all anterless adult moose~
(a) Without calves
(b) With one calf
(c) With two or more calves
4. Calves -moose 4 - 6 months old, smaller than adultso
5. Questionable -moose which could not be identified accurately
due to poor visability or flying conditionso
The number of hours actually spent searching for moose was recorded
for each area to determine the number of moose seen per flying hour. Sig
Olson, John Klingbeil, Jack Frost and Douglas Jones acted as observers
while Joe Miner, Stan Frede.ricksen, Harry Pinkham and Glenn Orton served
as pilots during the survey.
The areas covered were essentially limited to those supporting moose
populations subject to hunting pressure, wolf predation or both. Except
for the area between Salchaket Slough and tbe Richardson Highway, the
Tanana flats and Wood River areas covered in previous years were not in-
cluded, since hunting pressure in these areas is negligible. The areas
surveyed are shown in Figures 1, 2, and 3.
=125=
.•
FINDINGS
A summary of all moose tallied is presented in Table 1 by area.
Five hundred ninety-two moose were classified as to sex and age, plus
17 additional individuals which were not, for a total sample of six
hundred nine individuals. The total flying time for the entire proj-
ect, including the time spent traveling to and from the survey, Fwa.s
29.8 hours . The actual time spent counting moose on the areas was
19.8 hours. The total moose seen per hour based on total flying time
for the project was 20.4, and 30.7 moose were seen per hour during the
time actually spent looking for moose . The number of moose observed
per hour for the various areas is as follows:
AREA
Tanana Valley
Fortymile
Koyukuk
All areas combined
NO. MOOSE SEEN PER HOUR
24.7
40.0
34.6
The number of moose seen per hour is undoubtedly low, since con-
ditions for observation were extremely poor. Snow cover was light;
consequently, low brush, grass, stumps, windfalls and rocks projecting
through the snow presented constant distractions and hampered the ob-
serveris ability to see moose as compared to spotting moose against the
relatively even, overall snow cover prevailing in prior years.
Moose were not observed in sufficient numbers to allow statistical
analysis of the comparative differences in herd composition at different
elevations. No moose· were observed above timberline; the majority being
located along the tributary creeks and main river bottoms and flats.
The herd composition for all areas surveyed is summarized and presented
in Table 2.
PRODUCTIVITY
Tanana Valley Area -The calf~cow ratio dropped slightly from
47~100 in 1956 to 42gl00 in 1957. This is the third year that this
ratio has decreased (53~100 in 1955). Despite this fact, productivity
can be considered good. Althouth it is assumed that the cow segment
of the herd is the most constant, it is possible that the percentage
of yearling cows has increased due to good survival, and the calf:cow
ratio consequently would decrease__._ The calf percentage of the total
~126-
. ~--~·-; .·
•
herd still remains at 20 per cent; the same -level maintained since 1954,
w~ich would tend to indicate a uniform level'of production. The ratio
of twin calves per 100 cows dropped to the lowest point in three years
( 2 ~ 100) • Outwardly, there appears t.o .be a slight downward trend in pro-
ductivity over the past three or four years. A more direct comparison ·
between 1956 and 1957 is possible by excluding the Tanana Flats and Wood
River counts for both years, using only those counts from the Chena
River, Chatanika River, Shaw Creek, and the (}oodpaster River.-It is
evident in Table 2 that the data indicate very little change in the
past two years in this area.
Fortymil~ -The productivity index in this area decreased. some-
what from the previous year. Calves per 100 -caws d.i"opped from 53~100
in 1956 to 46~100 in 1957j and the, percentage of calves dropped from 24
to 19. Despite this fact, productivity in this area still is on par
with the Tanana Valley as well as areas south of the Alaska Range.
Eight cows with twin calves were observed in the Fortymile as compared
to no cows with twins per 100 cows with calves in 1956.
T4e reduced ratio of calves per 100 cows in 1957 might have been
caused by good calf survival from 1956 resulting in a larger number of
non-breeding yearling cows. In 1956, 28 .cows without calves and31 cows-
with calves were tallied (90~100) as compared to 34 cows without calves
and 23 With calves (148~100) tallied in 1957·
Koyukuk -The Koyukuk area showed the highest level of productivity
of any of the areas surveyed. The calf~cow ratio was 67gl00 and the
proportion of calves in the total herd was 28 per cent. A further indi-
cation of relatively high level of production was the incidence of cows
with twin calves· (23 cows with twin claves per 100 cows with calves).
The only comparable data available from previous years for this area
was obtained in 1954. Production was very good at that time as indi-
cated by a calf~cow ratio of 86:100 and a calf percentage of 26. The
ratio of_cows with twin <::alves was also very high, 36~100. It is evi-
dent that during the past four years, the level of productivity in this
area has been very high.
Unusually heavy wolf predation, aggravated. by a deep crusted snow
condition during the winter and early spring of 1957, was apparently
an important mortality factor. During March, the bounty hunter team
of Stickman ~d Huntington counted 175 dead moose believed to be-wolf
kills in 123 hours of flying time •
-127-
TABLE 1
A BULLS
R
E ~ A ~YOUNG ADULT
[: .. -
T'A1V'AN.k 'Vk.Iii:iEY I:
.. [:
Chena, Chatanika, i!
Shaw, Salcha Cr., I'
14 38 Goodpaster !
' 1: ,.
i
Tanana River "
( Sa1chaket) I 3 15
Above areas combineqj 17 53
i I
!:
FORTYMTI.iE
..
Mosquito Fork,
West Fork,
KechUI!.lstuk 12 42
KOYUKUK VALLEY
~ .........................
Hughes to Koyukuk
l!og R . , Hus:lil~ R , 14. 56 ' -· , .. ,, ~· ..::
-· GRAND TOTAL 43 151
[
SUMMARY OF MOOSE POPULATION COMPOSITION COUNTS
TANANA VALLEY, FORTYMILE, AND KOYUKUK
NOVEMBER. -DECEMBER 1957
... cows ~· CALVES
WI;THOVT WITH WITH
TOTAL CALF 1.CALF 2 CALVES TOTAL TOTAL
~a 44 31 1 76 34
.
18 26 15 0 41 15
70 70: 46 1 117 49
54 34 23 2 59 27
70 42 35 11 ·.
88 58
'
194 146 104 14 264 134
..
~.,.,...,. .... -
UNIDEN-MOOSE ACTUAL MOOSE
TIFIED FLYING SEEN
TIME PER
HOUR
TOTAL TOTAL.
6 168 7·8 21.5
'
0 74 2.0 37.0
6 242 9.8 24.7
1 141 3·5 40.0
10 226 6.5 34.6
17 609 19.8 30.7
11 .....
N ..c
n
TABLE 2 SEX AND AGE RATIOS -TANANA VALLEY, FORTYMILE AND KOYUKUK -1957
(Comparison with 1954, 1955, 1956 in Tanana Valley and 1956
in Fortymile)
..
YOUNG TWIN
TOTAL BULLS CALVES CALVES CALF
BULLS PER PER PER 100 '{o OF
PER 100 100 COWS TOTAL AREA SAMPLED YEAR 100 cows AD. BUT..LS cows W/CALVES HERD
TANANA V:AIJDEY'
Cheina, Chatanika., Shaw Cr.,
Salchaj Goodpaster 1957 68 37 45 3 20
1956 68 30 43 19 20
Tanana (Salchaket) 1957 44 20 37 0 20
Above areas combined 1957 6o 32 42 2 20
1956 83 47 25 5 20
1955 ·123 1: • --53 13 19
1954 85 --47 5 20
FORT;fMI:J.;E ·
Mosquito Fork, Ketchumstuk,
West Fork 1957 91 29 46 8 19-
1956 66 30 53 0 24
KOYUKUK R~VER
Koyukuk R. {Huslia to Hughes
Hog River, Huslia River) 1957 80 25 66 23 28
I
..... _ .. __
·~--··---
YOUNG YOUNG TOTAL
BULLS BULLS NUMBEF
'{o OF PER 100 MOOSE
TOTAL BULL IN
HERD CALVES SAMPLE
-
8 82 162
8 77 93
4 40 74
7 69 236 -
71 405 7
18 186 410
13 1~:?'7 109
8 89 140 I
7 6o 129
6 48 216
I
I
I
!
i
0 ...
'-'l
0
8
TABLE 3
A
R
E
A
TANANA VAiiL'EY
Chena, Chatanika, Shaw Cr.,
Salcha, ·~·Goodpaster
Tanana (Salchaket)
..
Above areas combined
FORTYMIIiE
-Ketchumstuk, Mosquito Fork,
West Fork
..
• •
TOTAL
cows
44
95
139
59
!
YOUNG BULL: BULL C.Ai.F RATIOS
(TANAN.kVALI;EY '& ·FORTYMILE)
1956.:57 .
1 9 5 6
TOTAL
BULL BULL CALF TOTAL
CALVES TOTAL COW cows
·-
9 21:100 76
23 24:100 41
32 23:100 117
15 25:100 59
I
~
1 9 5 7
TOTAL
.YOUNG
BULLS
14
3
17
12
YOUNG BULLS
TOTAL cows·
18:'loo
7:100
15:100
20:100
•
PERCENT
MDRTALITY \•
-·----
..
The young bull~ adult bull ratio in all areas ranges· from 25 to 32
per 100 and is indicative of' good overall production. It further re-
flects the light overall hunting pressure exerted on.-these herds. In
genera.J., productivity can be considered good despite a sligbt dowri.ward
trend from previous years f'o~ all three areas surveyed, and it compares
favorably with the Susitna-Matanuska area as well as the Copper River
Basin.
SURVIVAL (to 18 months)
Survival of' young bulls (to 18 months) can be measured in one of
two,ways, i.e., the ratio of yoUng bulls to bull calves of the year or
the ratio of bull calves to total cows for the past year as compared
to the ratio of' young bulls to total cows for the current year. The ·
reliability of the former depends primarily on uniform calf production
from year to year. The latter assumes that since cows are not hunted
and subject principally to natural mortality factors, this segment of
the population is probably the most constant and thus probably provides
the most reliable index to survival. The ratios of bull. calves and
young bulls to total cows for 1956 andl957 respectively: are presented
in Table 3·
Tanana Valley -The 1956 counts indicated a bull calf~total cow
ratio of 23~100 and the 1957 counts showed a young bull~total cow ratio
of' 15~100, indicating 35 per cent mortality. Only a moderate loss of
young male animals, probably mostly due to. hunting is evident.
Fortym.ile -The bull calf~ total cow ratio derived in 1956 was
25~100 and the young bull:total cow ratio similarly derived in 1957
was 20~ 100, thus showing a 20 per cent mortality. This reflects a
relatively high level of survival and the light hunting pressure ex-
erted in this area. The ratio of 89 y9ung bulls per 100 bull c::alves
in 1957 tends to substantiate the above although it is apparent that
the latter figures indicate a lesser degree of mo~ality.
Koyukuk -There are no data available for 195~ from which to derive
a bull calf:total cow ratio. Therefore, it is not. possible to determine
the survival of young males to 18 months on this basis. The young bull:
bull calf ratio ( 48: 100) suggests considerably heavier mortality of
young bulls than observed in other areas . This cannot be interpreted
as an accurate figure, however, since there is no way in which to ascer-
tain whether or not calf production has been constant in this area from
year to year. It may, however, reflect the allegedly heavy wolf pre-
datien ~uring the previous winter.
~131~
If predation resulted in a weak yearling male class, it is logical
that the female segment of the yearling class was similarly affected"
Conceivably, predation in the Koyukuk area should have taken a propor-
tionately larger toll of the calves, the most 1Kulnerable age class,
thereby affecting the yearling class represented the following fall.
Yearling fem,a.les are generally non-breeding and comprise a portion cff'
those cows recorded as "cows without calves". The areas with no seri-
ous predation problem should show a little higher ratio of cows without
calves compared to areas where hea"l.ry predation has occurred. In the
Tanana Valley and Fortymile area, the ratio of cows without calves to
100 total cows was 60:100 and 58~100 respectively. In the Koyukuk,
the ratio was 48:100. Since the yearling bull:bull calf ratio also
indicates the possibility of a higher degree of mortality than else-
where, it is possible that wolf predation would have materially af-
fected survival of the 1956 calf crop in the Koyukuk area.
EFFECTS OF HUNTING
Tanana Valley-The bull~cow ratio of 68:100 in the tributary stream
valleys and ratio of 44:100 in the Tanana flats indicates an overall ·
light to moderate hunting pressure in these areas. The ratio for the
·entire area is 60~100 and it is believed that the current hunting pres-
sure is in no way detrimental to the moose population at present.
Fortymile -The bull: cow ratio (91:100) in this area is high and
does not seem comparable to the ratio obtained in 1956 ( 66: 100). This
ratio suggests disproportionate sampling of bulls. Although a question-
able ratio has been obtained in the current counts, there is no doubt
that hunting pressure is not significant enough to substantially affect
the number of bulls in the population.
Koyukuk -Three native villages (Hughes, Huslia and Koyukuk) have
ready access to the area. Hunting is restricted principally to those
areas along or immediately adjacent to the rivers and streams navigable
by river boat. The ratio of bulls to cows is high (801100).
Hunting in all the areas surveyed is limited, for the most part,
to the navigable streams and rivers, roads and the areas immediately
adjacent to them. Some moose are taken by aircraft as well, however,
this accounts for a comparatively small segment of the kilL Very few
moose are taken over a half-mile from.a route of travel, which leayes
the major portion of these areas unhunted. · The road network out of
Fairbanks receives heavy pressure during the moose season and there is
~132~
....... '
..
no doubt that the bull population in local areas is depleted temporarily.
The large surrounding untapped reservoirs, however, serve to replenish
these areas over a period of time and the general effect of hunting on
the population as a whole is insignificant at present. Likewise, the
hunting in the Fortymile (Taylor Highway) is nearly all accomplished
from the road leaving the area a half-mile or more from the road practi-
cally untouched.
There are no moads in the Koyukuk region, thus travel is restricted
to river boats and an occasional airplane. It is again obvious that.the
area effectively hunted is only a small portion of the region as a whole,
and hunting in itself is not an important decimating factor at present.
RECOMMENDATIONS
Herd composition counts in the Tanana, Fortymile and Koyukuk areas
should be continued.;
Prepared by; Approved by~
SIGURD T. OLSON ROBERT F • SCOTT
Wildlife Management Biologist Supervisor of Game Restoration
DATE~ January 31, 1958
~133-
"
Job No. 7 Moose Management Studies -Stikine River Valley
Aerial Surveys
PERIOD COVERED: September 15 -December 31, 1957
ABSTRACT
Forty-one moose were killed on the Alaska portion of the Stikine
River valley during the 1957 legal season. Age compos~t:~n~determined
from jaws collected indicates a healthy population, with a large portion
of young animals represented in the kill. Aerial counts made in Decem~:er
shqwed a good herd increase with the average ratio being 37 calves per':,
100 adults,.
OBJECTIVES
To obtain a total population estimate and herd sex and age compo-
sition. To evaluate the hunter harvest.
T;~Jm'IQUES USED:.,-1;c;: -
During the legal open season, (Sep. 15 -Oct. 15), jaws were col-
lected from moose killed by hunters and all moose taken were tabulated
to record the total harvest. It is believed that an accurate record of
the kill was obtained, as Fish and Wildlife Service personnel were present
on the river and checked on kills throughout the entire season. Jaws
were segrated into age class groupings by examination of tooth replace-
ment and wear.
It was planned to make aerial composition counts in November prior
to the shedding of antlers by the bulls, however, unfavorable flying
weather and lack of snow cover delayed the counts. On December 17 counts
were finally made under relatively good conditions. A new show cover
orovided excellent contrast for spotting moose and flying conditions were
favorable, ~nth the exception of snow squalls in the Limb Island area.
A Cessna lBO was used for the counts, piloted by Bill Stedman, with
Da.ve Kleln as observer.
The Stikine River penetrates the Coast Range and reaches tide water
near the town of Wrangell. Moose occur along the entire river, from
interior British Columbia to the delta flats on the Southeast Alaska
coast.. Generally, the river is clo;sely flanked by rolling hills and moUn-
tains, but the lower forty-five miles of the river below the Great Glacier
runs through a flat valley three to four mil-es wide. A relatively stable
moose herd exists in this lower valley and there is little exchange of
animals with other areas. The greater portion of this area lies within
Alaska (30 miles)~
There are about 50 square miles of valley bottom along the Alaska
portion of the Stikine River$ Probably one-half of this is excellent
winter moose range, the remainder being intermediate in quality. An
estimate based on recent aerial surveys and a partial ground count made
-134-
.. ..
I
I
N
Scail.e:
1 inch= 4 miles
FIGURE 1. STIKINE RIVER WJ:N'IER MOOSE RA.NGE
I
ll'l
("")
.-1
I
(Shaded arem indicates extent of winter range)
in 1952 by Mammal Control Agent, Lee Ellis, in 'Which 126 moose or their
tracks were counted, places the population level of moose at 150-175 on
the Alaska side of the International Boundary.
Browse species are more varied and somewhat different than on moose
ranges in western Alaska. Dogwood, Comus stolonifera has the greatest
density and may be the most important winter food in this area. Willow
and cottonwood are of secondary importance and Viburnum, Elder and moun-
t,ain ash are also used, but are less numerous• Evidence of heavy-browsing
i$ apparent in some areas; however, generally, browse plants appear vigor-
ous and in good condition. Density of browse plants is much greater than
in Western Alaska~
The Stikine River moose herd is a valuable asset to Southeast Alaska,
offering an opportunity for moose hunting which is not generally available
tnroughout this region.
The Hunter Harvest: This year the total le-gal harvest of moose on
the Stikine River, within Alaska, was 40 bulls., In addition, one cow was
spot accidentally when a hunter 1.s bullet passed through a bull and struck
tbe cow standLng behind it. Three more moose were also shot in the Muddy
R~ver-Thomas Bay area.
This substantial kill, the largest on record for the Stikine River,
was brought about through increased hunting pressure under favorable
weather conditions over a one month season. Although small boats with
outboard motors are the main mode of transport for the hunters, airplanes
were used extensively this year for transporting hunters and equipment
to and from camps and for reconnaissance flights to survey terrain and
locate moose. A summary of the moose kill on the Stikine River from
1952 -1957 is shown in Table 1, with the length of seasons, number of
hunters and hunter success.
TABLE 1. Total Kill and Hunter Success Ratios on the Stikine River, Alaska,
in Relat:.ion to Lengthof Seasolf, 1952-1957 ..
Length of Est~ No. Noa of Moose Percent
Year Season of Hunters Taken Success
1952 Septo 15 -Oct. 14 300 31 10
1953 Sept. 15 -Sept. 30 100 12 12
:\.954 Sept. 15 ~ Oct. 5 125 14 ll
1955 Sept. 15 -Oct. 5 150 16 ll
1956 Sept. 15 -Oct. 5 125 30 24
1957 Sept. 15 -Oct. 15 160 40 25
Averages 160 24 16
-136-
Restricted travel, due to low water levels, resulted in a reduced
moose kill on the British Columbia side of the border in the Iskut and
Katete river areas this yeare It is believed seven moose were taken from
this areae Normally, about 10 = 12 moose are killed each year on the
Canadian side of the boundary by Alaska hunters employing the Canadian
guide» Walter Simpsono
Bulls killed late in the season~ (Oct~ 10 ~ 15)J were still in
excellent conditione Several hunters taking these late moose reported
no offensive flavor to the meat" The rut3 which was apparently initiated
by this date 9 was not reflected in deter!oration of the physical condition
of the bullae Sex:~al-pr~siological ch~~ges associated with the rut are
:mi.ni.m.al in young bulls and t.heir large representation in the kill may
account for the high q~ty of the meate
The age composition of the kill continues to show a large proportion
of young animalss as has been the case in past yearso Such an age struc=
ture reflects a heavily harvested and healtny population~ which.is quite
likely increasing in numbers., The gradually inqreasingamiual harvest
over the past severai years is apparently a product of this herd increase&
The age class distribution of moose killed in the 1957 harvest is shown
in Table 2, as determined from jaws collected from 21 bulls& Although
the number of jaws collected was small it represents a random sample of
the animals killedo
TABLE 2.., Age Class Representation of Hunterc·....Killed Moose on the Stikine
River during 1953=1955 and 1957~ (From aged jaws collected)o
1953 1954 1955 1957
Age Class ~No .. Jaws ~No.,. Jaws % No .. Jaws ~ No,., Jaw!.
I (15=17 months) 18 2 8 1 58 7 57 12
II (2 yrs,. 3=5 mos.,)-55 6 33 4 8 1 :29 6
III (3 yrsv & older) 21 3 58 7 33 4 14 .3
Totals 11 12 12 21
Aerial Counts~ Complete Coverage of the Alaska portion of the Stikine
f.
River Valley is attempted"in making·the a.e:dil count~.,· howevel;"~ the'il'l.ter= :e
spersion of' spruce timber throughout the valley offers concealing 0over
for the moose 9 ConsequentlyJ the counts obtained more nearly reflect.
trends in population size~ A· summar.y of the aerial counts is presented in
Table 3., The breakdown of cal. ves to adults indicates a fa.wrable increase
this yearo Ratios varied from 25 calves per 100 adults on the lower river;
to 56 calves per 100 adult!!! on the upper :rivero The average for the whole
valley was 37 calves per 100 adults., These ratios compare favorably with
the lower Susitna=Ma.tanuska Valley moose herd ratios of 31 calves per 100
adultsa Removal of a large portion of bulls by hunting prior to the counts)
undoubtedly, contributes to this high calf~adult ratio on the Stikine0
=137~
\
Segration of bulls and cows was not possible. Antler shedding had
started, and in addition, the small size or the antlers or moose in this
area, the turbulent air conditions usually encountered, and the abundance
of vegetative cover, make aerial differentiation of sexes unreliable.
Only one large antlered bull was seen; however, antlers on yearling bulls
in the dense brush or scattered spruce could easily have been overlooked.
TABLE 3o Aerial Moose Counts Made on the Stikine River, Alaska, December
17, 1957.
Area Adults Calves Unident. Total Cal ves/100 Adults
Lower River
(flats to Kakwan Ft.) 27 7 3 37 25
Upper River
(Kakwan pt. to
Int. boundary) 16 9 25 56
Totals 43 16 3 62 37
RECOMMENDATIONS
Annual aerial composition counts and the collection of harvest infor-
mation should be continued to maintain a current knowledge or the welfare
or this important moose herd. Effort should be continued to secure counts
or bulls under favorable conditions soon after the hunting season. There
is a need for additional study to explain variations in calf:adult ratios
on the upper and lower rivers.
Prepared by:=-_,...~~=-~---__;Approved by: David B.. Klein ::::'Ro-;b:-e-rt~-=F=-.--=s-co-t~t=-------
\'lildlife Mgt'ii, B~<?,lo~'ti Supervisor, Game Restoration
Date: December 31, 1957
-138-