HomeMy WebLinkAboutAPA4116
TK
1425
.S8
B54
no.4116
MOOSE MANAGEMENT STUDIES
Volume 13, number 2
Job Completion Reports
May 1, 1959
Note from Alaska Library Resources and Information Services:
This document is related to later moose study documents that had been used as supporting
documentation by the Susitna Hydroelectric Project and that appear in the Susitna
Hydroelectric Project document index. Job numbers 1, 2, and 3 cover the Susitna River
basin.
Therefore, Alaska Library Resources and Information Services has assigned APA no. 4116
to this document and has included it in the Susitna Hydroelectric Project collection. Pages
for Job numbers 4 and 5 are included to make the document complete.
There is a blur on p. 6. That line reads:
"Rivers to the Cook Inlet, the Little Susitna River, the Knik River,"
Volume 13
JOE COMPLETION REPORTS
Project W-3-R-13 Alaska M~y 1, 1~5'
Wildlife Investigations
Work Plan A
MOOSE MANAGEHENT STUDIES
Personnel
Sigurd T. Olson, Acting Supervisor, Game Restoration
David R. Klein, Wildlife Management Biologist
Ro'Dert A. Rausch, " 11 11
Ronald 0. Skoog, " 11
"
Ur'han C. Nelson
Number 2
Acting 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Not for Publication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).
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CONTENTS
Job No. Title Page
Sllilllll.acy. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • i
1 Herd Composition Surveys--Susitna and Copper.
~iver Valleys ..........................•........... 1
2 Moose Calving Studies •....••.•••••••••••••••••••••• 27
3 Distribution, Movements, and Dynamics of Railbelt
Moose Pdpu!~tions •••••••.••••..••..•.•.•••.•••..••• 42
4 Herd Composition in Interior Alaska •••••••••••••••• 43
5 Southeast Alaska Moose Studies ••••••••••••••••••••• 53
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SUMMARY
Job. No. 1.--Herd c-omposition Surveys--Susitna and Copper River Valleys
-sex and age composition counts of moose populati~ns inhabiting
the Lower Susitna and Matanuska Valleys, and the Upper Susitna and
Copper River Valleys were conducted in October and November of 195S
with the following results:
1. Eight thousand seventy-five moose were tallied in 64.1
hours of flight time actually counting moose.
2. Productivity in both areas is good with an average of 42
and 37 caJ. ves per 100 cows respectively.
3. Survival of yearling bulls 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 rat:ios.
'These reveal that in areas accessible by road or to swamp
buggies the bull segment of the population is reduced. .This
reduction, however, has not been demonstrated to affect the
pregnancy rate; thus hunting of bulls only does not contirol
herd size.
Job No. 2.--Moose Calving Studies
Aerial counts of moose inhabiting calving areas are most success-
ful in the early morning, between 3 a.m. and 7 a.m. Pregnant moose
seek a variety of vegetation types for calving, but apparently concen-
trate in lowland, marshy areas that provide a variety of early-spring
food and escape cover.
Moose calves first were seen on May 11, in 195S. Calving prog-
ressed rapidly and peaked on May. 25 or 26. The final crop, estimated
from aerial counts and from in utero observations~ was 109 calves per
100 cows of Age Class I or older (24 months or older at the time o£ the
parturition counts).
Twins occ:ur in about 30 percent of the pregnancies, and two sets
of triplets were observed.
Aerial counts made when the calves were about six months old<
revealed a calf mortality of 45 to 60 percent. Mort.ality appro:x:ima.ting
this magriitud~ has been relatively constant in the Valley areas for a
number of years and may be normal under the environmental conditions
existing on the study areas. Survival of twin varies considerably: from
area to area. Specific factors affecting overall calf survival and
survival of twins are not known.
i
Job No.3-Distribution, Movements, and Dynamics of Railbelt Moose
Populations.
No work accomplished on this job.
Job No.4--Herd Composition in Interior Alaska
Aerial composition counts were conducted during November and
December in the Tanana, Fortymile, and lower Koyukuk Valleys. Eleven
hundred nine moose were tallied in 19.3 hours of aerial counting for
an average of 57.4 moose per hour.
Productivity indicated by calf:cow ratios, twins per 100 cows
and the calf percent of the total herd remaiQ.s· "good" in all three
areas.
Survival of moose to the yearling stage in the Tanana and
Fortymile area is higher: than that observed in the Koyukuk.
The effects of hunting in all three areas has little effect on
the m~ose populations as a whole. Hunting pressure is quite localized
in all three areas, since access is limited to those areas immediately
adjacent to the roads and rivers.
There is still a decided need for study to provi,de data which
will enable the investigator to better evalua:te the effect of the many
variables affecting composition counts from year to year.
Job No. 5--Southeast Alaska Moose Studies
Thirty-one moose were killed on the Alaska portion of the Stikine
River during the 1958 legal season. Age composition of the kill con-
tinued to reflect the heavy cropping of bulls. Hunter success contmued
high for the area at 23 percent. Composition counts showed minimum
ratios of 41 calves per 100 cows which are comparable to heavily hunted
areas in the Matanuska Valley. An estimate of the moose population on
th~ Stikine River based on pre-hunting season sex and age ratios and age
distribution of the hunter-kill indicate a post. hUnting season popula-
tion of 310o
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JOB NO. 1. --Herd Composition Surveys--Susitna and Copper River
Valleys
PERIOD COVERED: September 1, 1958, toNovember 26, 1958
ABSTRACT
Sex and age composition counts of moose populations inhabiting
the Lower Susitna and Matanuska Valleys, and the Upper Susitna and
Copper River Valleys were conducted in October and November of
1958 with the following results:
I. Eight thousand seventy-five moose were tallied in
64. 1 hours of flight time actually counting moose.
2. Productivity in both areas is good with an average of 42
and 37 calves per 100 cows respectively.
3. Survival of yearling bulls 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 swamp
buggies the bull segment of the population is reduced.
This reduction, however, has not been demonstrated to
affect the pregnancy rate; thus hunting of bulls only does
not control herd size.
OBJECTIVES
To determine age and sex composition of identifiable local
moose population 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 during late October
and November. The Upper Susitna and Copper River Valleys were
surveyed between October 26, and November 2, using a Supercub
150, piloted by Gene Stolz of the Aircraft Division. Flying _time,
actually spent counting moose, totaled 35. 5 hours.
-1-·
Snow cover in the Lower Susitna Valley was not adequate for
counting moose until November 12, and the counts were completed
on November 26. .
The counts were made with a Supercub 150, except on the
Fort Richardson Area where the desirability for maintaining V. H. F.
radio contact with the Military Control towers prompted the use of
a Gessna 180. The planes were piloted by the following Game
Manag~ment personnel: Jim Branson, agent in charge, agents
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hours wer.e spent actually countir1g moof!e.
The counts were made within each predetermined local area
from an altitude of 300 to 600 feet depending upon terrain, ground
cover, and moose visability factors, (principally light and snow
conditions}. Each moose seen was inspected and assigned to a
sex. and age cat;egory. If 9oubt concerning. its category existed, a
low level inspection pass, was made. Neither total 9ounts nor
systematic samples were practicable due to the lar&e area involved.
An -attempt was made, howev.er, to spend a proportionate amount of
time c9unting in each cover type, and at the ·various altitudinal
levels within each local area. The sex and_ age distribution patterns
of the moose populations were not known exactly, prior to counting,
therefore pre,s~nt techniques do not always produce a truly representa-
tive sample. Some of the lo.cal populations represe~ted in the data
have, however, been studied for a number of years.' The kn.qwledge
obtained relative to the seasonal distribution of moose has resulted
in modification of counting techniques, yielding more representative
samples. As knowledge of population characteristics accumulates
the problems of sampling techniques should diminish~
Data Recorded
Moose sex and age determinations by aertal obse;rvers are
limited to five categories:
1. Young bulls--bulls with spike or forked antlers, usually
with little or no antler-palm development. These animals
are predominantly "yearlings". approximately eighteen
months old. There is some overlap with two-and three-
year~old. moose. The errors are believed compensating
however~ because unusually small antlered two-and three-
year-olds are counted as yearlings and large antlered
yearlings are placed inthenext.higher age category.
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2. Medium bulls--bulls having some antler-palm develop-
ment, but not massive appearing; probably two-and
three-year-old animals. The medium-bull category's
most useful function is to create an awareness of the
size differential between young and adult bulls, and it
does not provide clear=cut data useful in determining
population trends. -Animals in the medium-bull category
are considered adults in calculating sex and age ratios.
3. Adult Bulls--all bulls having greater antler development
than the preceeding 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 1958 sex and age composition counts were
analyzed to determine current productivity, survival, and effects
of hunting in each identifiable population as well as for the moose
herds in general. The indicators of population status were first
described in Federal Aid Progress and Completion Reports as
follows: Federal Aid in._Wildlife Restoration (Alaska), 10 (3) 7-11,
restated and modified in :1:2 ( 1) 3="6. The indicators are again
stated, with several additions, below. Each. are evaluated by
examining one or more indices provided by the appropriate sex
or age ratios.
··Productivity--the initial incidence of live births to females
in the population, and the subsequent 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.
A secondary indicator of productivity is the ratio of twins
per 100 cows with calves. The full significance of this ratio is
not fully understood at present. Nevertheless, in certain areas
the ratio of twins per 100 cows with calves approaches 25 per 100
and adds a significant number of individuals to the herd. In some
populations, such as the Mts. Susitna:..Beluga area, the high
incidence of twinning is concurrent with excellent productivity.
The Matanuska Valley populations which have a sustained record
of good to excellent productivity have a relatively low ratio of
twins per 100 cows.
-.3-
The observed variations in twinning rates may reflect a
number of survival factors rather than differences in twinning
rates at nat~lity. In the Matp.zlUska Valley examination of the
contents of nearly 100 uteri taken from cows collected during
the period when moose a,re normally pregnant~ revealed 27 sets
of twins per 100 pregnancies. Aerial counts made on the same
areas during May and JU.ne f958~ indicated 33 sets of twins per
100 cow's with calves •. The data obtained from the i:n: ute.ro and
. calving area observations suggest that in the Valley areas
mortality rates.for twins are greater than they are for singletons.
'The r~asons for certain other areas having higher ratios
of twins are not known~ but 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 produchvity
in this report. The terms correspond to the following numerical
values:
Poor-------~------=--below 20 calves per 100 cows
Fair----::--=----------20 to 35 calves per 100 cows
Good---:.-------------36 to 50 calves per 100 cows
Excellent----------=':"'-more than 50 calves per 100 cows
The foregoing categories pertain only to productivity at
approximately six months a.s measured by the calf:cow ratio.
They do not necessarily indicate the overall well-being of the
herd. A population having poor productivity, at six months,
could have excellent survival during the remaining portion of
the year and be increasing; conversely a population could have
excellent productivity, poor survival and be decreasing.
Survival--The survival of the calves recorded on the fall
sex and age counts to approximately the same date one year later--
i.e. , survival from approximcttely 6 to 18 months of age; and as
survival of calves recorded on the spring or parturition counts to
the same date one year later--i.e., survival from birth to
12 months.
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Survival between 6 and 18 months can be measured by two
indices, each using a different population segment as its comparison
base. The first index is the ratio of young (yearling) bulls per 100
bull calves. In computing the young bull :bull calf ratio it i's
necessary to assume that calf production and survival to the time
of the counts remains constant from year to year, and that the
sex ratio of moose calves is 100:100. Calf production and sur-
vival to the time of the counts could vary considerably :fi·om year
to year and cause an. error in the index. Sex composition data
obtained from examination of moose fetuses and calves indicate,
essentially, a IOOto 100 ratio.
The second index to survival from 6 to 18 months is pro-
vided by the ratio of young bulls per 100 cows as compared to
the previous year's ratio of bull calves per 100 cows. Theoreti=
cally, the difference between these ratios represents the mortality
·during the period between 6 and. 18 mont:hs. The percentage
obtained from these methods should not, at present, be interpreted·
as absolute, because the aerial surveys possess a number of
seemingly inherent variables that have not been fully evaluated.
The comparison does, however, yield data useful in interpreting
population trends.
Cow moose are probably the most constant population seg=
ment in Alaska where they are not hunted. They are therefore used
as the base for comparing young bulls with last year's bull calves.
The use of the female population segment as the comparison base
for the survival index assumes that natural mortality of adult
females is approximately equal to the annual recruitment ofyearling
females, which a.re colinted as adults by aerial observers. In
populations experiencing either a rapid increase or decrease the
described indexw:i.ll be biased. Most d. the moose populations in
South Central Alaska, however, appear to be nearly stable or
increasing slowly. the index is therefore believed to provide a
reliable index to survival, providing that the various sex and age
components of each population are sampled proportionately.
A comparison base comprised of only those females two years
and older could be used, but at present it is not considered necessary.
The segment of the female population two years and older is computed
by assuming a 100 to 100 sex ratio in yearling moose and then sub-
tracting a number equal to the number of young males counted from
the total females counted. The previous yearus mortality is offset
by the. recruitment of last year 3 s yearling females to the base or
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comparison segment of the female pQp\l).ation. The foregoing
method provides an older and perhaps more stable age group for
compari,.son purposes, bu~ does not provide fo.r differential sex
survivai· rat.e~ to two yea.rs. I;n •. s.om.e areas hunting is a major
. decimating factor to . .Yc,.earling bull.sJ a.nd. would cause a significant
error to the s.tirVhlal index in the areas experiencing intense
hunting. pressure~
An index to survival of moose from 6 months to 12 months
_is provided by a,erial counts madein May and early June of 1957
. and 1958. The.faU counts have a numb_er of previously discussed
variables that are difficult to quantitate, and that tend to reduce
the value of the survival indices.· The spring counts possess
fewer known .. variations, and mortal~ty of moose from 12 to 18
months is believed minimal, except to hunting •. Thus, the spring
survival counts serve as an index to neffective survival". This
provides a measure of calves surviving to .one year, an.d under
our existing regulations, a measure of the yearling bulls which
will be available to hunters the following :fa:Jl •.. The spring survival
index is the ratio of calves per 100 cows il1 the spring as compared
. to the same .ratio obtained from.. the previous falls• sexand age
count •. Calf moose remain with th,e cow until she bears another
·.calf, usually the following spring •. At parturition the female drives
the last yeax~-s calf away. The calf does not leave the immediate
area. for several days, however, and spring calf:cow counts are
feasible until. early June ..
Effects of Hunting ... -The exteil.t to which hunting reduces the
male segment of the population is m.easu.rtd, primarily, by the
ratio of bulls per 100 cows •.. Another hi.de~ is the ratio of young
-bulls per iOQ adult bulls, how-ever, hunting tends to lower both the
number and average age of the .bull segment of the population; thus,
the yearlings COl1stitute a greater po.rti0 n of the bull population. as
hunting pr.essure increases.
FINDINGS
Sex and.Ase Comeosition of the
~ower Susitna Valley Moose Po;eulations
The gener~l areas of the Lower Susitna. and Matanuska
· 'Valleys are illustrated in Figure J ... The areas include the drain-
. ages of the Big. Susitna River -from the Talkeetna and Kahiltna
· Rivers to U..a&IM lplet,. the Little Susitna River, the Knik River,
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and the Matanuska River. Several additional drainages adjacent
to Anchorage are also included in the surveys.
The Lower Susitna and Matanuska Valleys support some of
Alaska's most abundant, accessible, and valuable moose popu-
lations, as well as some of the least accessible. ,Whenever possible
the areas outlined in Figure 1 represent identifiable moose popu-
lations believed to be resident within a specific geographic unit.
The M:atanuska Valley and Vlillow areas represent local identi-
fiable populations which have been studied for several years. The
basis for classifying them as identifiable populations was reported
in the following reports: Federal Aid in Wildlife Resto-ration
(Alaska) 11 (2): 19-22., and 12 (1}: 28 ... 110.
The study areas are as follows: Matanuska Valley, Willow
area, Kashwitna area, Susitna Flats, Mts. Susitna and Beluga,
Kahiltna glacie.r_ arE;)a, and Fo.rt Richardson area.
Each population indicator is discussed separately below,
as it applies to the general area and to certain local areas.
Productivity
Productivity throughout the Lower Susitna and Matanuska
Valley areas is considered good. The combined, and weighted
average calf:cow ratio for the entire area is 42 calves per 100
cows (Tables 1 and 2), and compares favorably with the 1957
calf:cow rat~9 of44 calves per 100 cows (see Table 7). The calf:
cow ratios are remarkably similar in the local areas comprising
this general area. The Kashwitna and Susitna Flats areas are
exceptions with calf:cow ratios of 35 and 32 .calves per 100 cows,
respectively. The Kashwitria calf:cow ratios for 1957 and 1958 are
identical. The reasons for the relatively low productivity in the
Kashwitna area are not clear, but it is: believed to reflect poor
survival of-calves rather than a low birth rate. Studies:_· of moose
pregnancy rates, through examination of railroad-killed moose,
reveal that at least 90 percent of all females Age Class II and
above are pregnant. Aerial surveys made at parturition time,
May and early June, also revealed a uniformly high calf;cow
ratio in 1958.
The mortality factors affecting calves are not fully known.
One theory is that the combination of deep snow and insufficient
winter browse adversely affects the females ability to care for
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Fi.g!;l.re_· 1. Moose populations in the Lower Susitna and Matanuska Valley
areas.
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20 Miles
1. Matanuska Valley
2. Willow Area
3. Kashwitna Area
4. Susitna Flats
5. Mts. Susitna & Beluga
6. Kahiltna Glacier Area
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7. Ft. Richardson Area C 0 0 K INLET
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Table I. Summary of moose population composition counts--Lower Susitna-Matanuska Valleys--November
and December 1958. ·
Yearling~ ~Medium La;ge-Total Females Females . Females Total Total Total
Area d d d Males -W /0 W/1 · W /2 Females Calves Moose
Matanuska
Valley
. Will ow Area
25
22
Kashwitna Area 84
Susitna Flats 14
23
17
71
13 ,
6 54
37 76
201 356
14 41
487 361 25 873 411 1338
292 169 15 476 199 751
390 159 21 570 201 1127
45 19 1 65 21 127
1 Mt. Susitna-
'f ·Beluga
Kahiltna
Glacier Area
Ft. Richardson
Area
Totals
8
30
22
205
11 43 62
25 82 137
21 28 71
181 411 797
52 27 7 86 41 189
95 57 6 158 69 364
139 85 6 230 97 398
1500 877 81 2.458 1039 4294
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Table 2. Sex and age ratios in Lower Susitna &: Matanuska Valley moose populations--Nov.&: Dec. 1958
Matanuska Valley 6
. Will ow J\r ea 16
K.ashwitna Area 62
Susitna Flats 63 "
Mt. Su sitna &:
Beh~ga 72
Kahiltna Area 87
Ft. Richardson 31
Totals 32
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43
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42
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32
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42
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12 18
5 17
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10 19
7 24
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2 11 3 1338
3 22 5 751
7 84 15 U27
11 133 22 127
4 39 9 189-
8 87 19 364
6 45 10 398
5 39 8 150 4294
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the newborn calves. Quantitative data on the Kashwitna area
supporting the above theory is lacking. The Willow area which
is adjacent to the Kashwitna area experienced severe winters
in 1954-55 and1955-56. ProductiviLy as shown by calf:cow
ratios obtained the following falls was only fair. Since 1956-57,
winters have 'J:>:een relativ.ely mild. and the calf:cow ratios in
.1957 and 1958 were 35 and 42 calves per 100 cows, respectively,
whereas the 1956 fall counts revealed only 27 calves per 100 cows.
In all prqbability snow depths· in the Kashwitna and Willow areas
are similar. Data indicating the comparative availability of
winter browse are not available, nevertheless the calf:cow ratios
are somewhat different, although, it is possible that the difference
is related to sampling error.
The Matanuska Valley and Kenai areas also seem to reflect
increased productivity of calves following warm winters. The
Matanuska Valley has had relatively mild winters since the
severe winter of 1954-55, and calf production increased from
34 per 100 cows in 1955 to 53, 50 and 47 calves per 100 cows in
. 1956, 57, and 58, respectively. Productivity on the Kenai has
been even n:tore dramatic, increasing from a low of 19 calves
per 100 cows in 1955 to 24, 35, and 42 calves per 100 cows in
1956, 57, and 58, respectively.
Refuge Supervisor Spencer, reports that the increased
productivity on the Kenai is concurrent with increased production
of browse on a large burnwhich occurred in 1947. The relative
importance of the mild winters as compared to that of an increased
supply of browse are seemingly impossible to separate. fu all
of the areas discussed, factors other than mild winters and the
resulting increased availability of browse may be affecting the
survival of calves, however, if such factors are present they are
not currently known.
The incidence of twinning in.the Lower Susitna and Matan;..
uska Valley areas, unlike the calf:cow .ratios, is quite variable.
The ratio of twins per 100 cows varies fro-m a high of 26 per 100
in the Mt. Susitna and Beluga area to a low of 6 per 100 in the
Matanuska Valley areas. The problems of interpreting the
significance of twins are discussed in the Section on Techniques.
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Survival
Survival of moose calves to _12 months in the Lower Susitna
Valley and Matanuska areas as r_evealed by spring aerial counts
(Table 3) is unusually good. The areas surveyed had a fall calf:
cow ratio of 50:100, and the following spring a calf (11 to 12
months) :ratio of 45:100; a measurable mortality of 10 percent
from November to May. This low mortality may well reflect
the mild winter of 1957-58. The mortality figure cannot be
considered exact, because it is impossible to determine if the
fall and spring counts are equally representative of the popu;.· ··
]atfcns sampled. In my opinion they are equal.
Survival of young bulls to 18 months is only fair. The
1957 bull calf:cow ratio was 22:100, and the comparable ratio,
young bulls per 100 cows, in 1958 is 8:100, this indicates that
more than 50 percent of last year's young bulls were removed
by hunting or other mortality.factors (Table 4). Examination
of survival by area (Table 4) reveals that young bull survival
varies greatly. The areas that are accessible and receive
intense hunting pressure, notably the Matanuska Valley and
Willow areas, have young bull:cow ratios of about 5 per 100.
Comparison of the young bull:cow ratio with the previous years
bull calf:cow ratios in the Matanuska Valley and. Willow areas
reveal a mortality of 70 to 90 percent 3 with hunting probably
the most important decimating.factor.
Survival in the more inaccessible areas, such as the
Kahiltna Glacier and Kashwitna areas was good. These areas
had an indicated survival of male calves, as measured by the
young bull :cow ratio, and the young bull :bull calf ratio, of
approximately 85 percent.
The indices to survival of 18 months are influenced by
hunting pressure and do not adequately measure survival of
female moose, which are not hunted. It is believed that the
spring aer.ial counts are a better index to survival of female
moose, because mortality between 12 and 18 months is con-
sidered minimal.
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Table 3. Survival of moose calves to 12 months as measured by the
yearling:cow _ratio obtained froin aerial counts made in
the Matanuska Valley and Lower Willow areas.
Date Total Females Total Yearlings Yearling :100 females
May 7, 1958 60 31 52
May 9, 1958 85 25 29
May 12, 1958 166 67 40
May 16, 1958 112 61 52
May 19, 1958 101 40 40
May 21, 1958 106 53 50
May 24, 1958 87 44 50
May 27, 1958 79 32 41
June 3, 1958 84 42 50
Average yearling :female ratio 45
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-1.3-
Table 4. An index to the survival of Bull Calves to 18 months.
Area
Bull calves :100
Cows 1957
L~ Susitna & Ma:ta;n:u.ska
Valleys
Matanuska Valley
Willow
Kashwitna
Kahiltna Glacier
Susitna & Beluga Mts.
Ft. Richardson
Totals
U;e:,eer Susitna -Co;e:eer
River Valle~
Lake Louise
Maclaren River &
Clearwater Creek
Alphabet Ridge
Oshetna Rivers & Tyone Cr.
Little Nelchina
Oshetna & Nelchina combined
Clarence L. & Black River
Mt. Drum & Wrangell Mts.
'Upper Gakona River
Kiana River and Lower
Chugach Mts.
Totals
25
17
17
2'1
27
22
22
33
18
18
27
24
26
25
20
22
12
21
..,.14&.
· lnd1ca'ted
Young bulls :100 pe-r·o:em:~ ··
Cows 1958 survival
3 12
5 29
15 8.8
19 90
9 33
10 45
8 36
7 33
12 67
11 61
13 48
7 29
11 42
11 44
12 60
13 59
10 83
11 52
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The Effects of Hunting
In order to more effectively demonstra1;e the effects of hunt-
ing on the bull segment of the 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 Vallev. The Matanuska Valley represents an
area of nearly unlimited accessibility by car and foot in the lowlands,
and a corresponding accessibility to swamp buggies and tracked
vehicles in the timberline areas. The Valley has an overaU bull:
cow ratio of 6:100. The bull:cow ratio has declined steadily for a
number of years. The ratio in 1956, 57, and 58 was 10, 8, and
6 per 100, respectively. These figures indicate unusual hunter
efficiency in harvesting bulls. -This past fall 1338 moose were
represented in the Matanuska Valley sample; only 54 were males,
Age 6lass I or older. There is no indication_ that this harvest of
males has in any way lowered the annual calf crop. A sample of
22 females Age Class Il and older collected during late 1958 and
early 1959 revealed a 100 percent incidence of pregnancy. In all
probability the hunter harvest will not significantly reduce the
bull percentage below its present level, because the principal 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. The bull:cow ratio of 16:100 reflects this
utilization. The area has an expanding system of roads and trails,
providing hunters better access to the moose population. Hunter=
success in 1958 was good and the decrease in the bull:cow ratio
from 28:100 in 1957 to 16:100 in 1958 may reflect increased hunt-
ing pres sure.
Kashwitna Area. The bull:cow ratio is 62 per 100. Hunting
is limited to the areas adjacent to the railroad, and to the few
'lakes suitable for float or ski-equipped airplanes. The bull moose
concentrate in the foothills of the Talkeetna mountains during the
first season and most of the second season, and are not generally
available to hunters. Apparently, hunting is not greatly affecting
the male portion of the population at present.
-15-
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Susitna and Beluga Mountains and Kahiltna Flats. These
areas· are accessible only by airplane, and have very few lakes
· or landing strips suitable for safe airplane operations. The
bull:cow ratios are 72 and 87 per 100 respectively, and reflect
the limited accessibility to hunting.
Fort Richardson. The Fort Richardson military reserva-
tion which.is closed to hunting has a bull:cow ratio of 31:100.
The moose population inhabiting Fort Richardson apparently is
hunted intensively on the periphery of the closed area. During
the first season many of the moose are located outside of the
reserve; particularly in the Chugach mountains and. Eagle River
areas where hunting is legal. The legal kill apparently is
sufficient to significantly affect the l:iull:cow ratio.
Sex and Age Composition in the
Upper Susitna and Copper River Valleys
The local areas corrip.rising this region are illustrated
in Figure 2. In general the region includes most of the tributaries
of the Susitna River above Deadman G-eek, the Nelchina Basin,
and the Copper River and its tributa-ries from the Tazlina River
to the Sanford River.
The populations identified in Figure 2 and Tables 5 and
6 represent, primarily, geographical divisions. When more
detailed studies are possible, segregation of some of these
areas into local identifiable populations seems probable.
The areas covered are as follows: Lake Louise, Maclaren
River and Clearwater Creek, Alphabet Ridge, The Oshetnas and
Little Nelchina Rivers, Clarence Lake and Black River, Mount
Drum and Wrangell Mts. , Upper Gakona River, and Kiana River
and Lower Chugach Mts.
In Tables 5 and 6 several of the above areas have been
subdivided; however, the combined totals for each geographic
area are used to analyze the population trend indicators.
Productivity, survival and effects of hunting, the indicators of
population trends, are again discussed in order.
-1.6-
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Key to Moose populations in Upper Susitna & Copper River Valleys:
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1. Lake Louise Area
2. Maclaren River and Clearwater Creek Area
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L 4. Oshetna Rivers Area
5. Little Nelchina Area
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[ 7. Mt. Drum and-Wrangell Mts. Area
8. Upper Gakona River Area
[ 9. Kiana River and Lower Chugach Mts. Area
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Figure 2
Hoose populations in Upper
Susitna & Copper River
Valleys.
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Table 5. Summary of Moose Population Composition Counts--Upper Susitna & Copper· River Valleys
Young~ -:tVIemum -Large TotaT -F'emare·s~ Females Females -Total Total Total
Area .Males Males Males Males w/o w/1 w/2 Fanales Calves Moose
Lake Louise 3 6 19 28 26 17 2 .O::b5 21 94
Maclaren River 61 53 118 232 316 194 7 517 208 957 Clear Creek
Alphabet Ridge 63 87 237 387 371 192 4 567 200 1154
Oshetna Rivers & 17 28 48 93 69 58 7 1~~4 72 299 Tyone Creek
Little NelChina 3 9 15 27 26 18 0 4b4 18 89
. I ~ Oshetna & Nelchina . I areas combined 20 37 63 120 95 76 7 178 90 388
Clarence Lake & 22
Black River
26 123 171 129 63 5 . 197 73 441
Mt. Drum 13
Wrangell Mt. area
33 103 149 71 34 1 106 36 291
Upper Gakona River 11 11 39 61 50 32 2 84 36 181
Kiana River & 13 23 99 135 109 14 1 12:4 16 275
Lower Chugach Mts.
Totals 206, 276 801 1283 1167 622 29 1818 680 3781
---:
Table 6. Sex and age ratios in Upper Susitna and Copper River Valleys--November 1958
§
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Lake Louise 62 12 47 10
Maclaren R. 45 36 40 3 Clear'Creek
Alphabet Ridge 68 19 35 2
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1\) ? Oshetna Rivers 69 22 53 11 & Tyone Creek
Little N elchina 61 13 41 0
Oshetna-Nelchina
Combined 67 20 50 8
Clarence Lake 62 15 37 7 and Black R.
Mt .. Drum-140 10 34 3 Wrangell Mt.
Upper Gakona R. 73 22 43 6
Kiana River & 108 L. Chugach Mt. 11 13 7
Totals 71 19 37 4
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ProductivA.ty
Productivity in the Upper Susitna and_ Copper River Valleys
is considered good. The 1958 fall counts indicate an overall
average of 37 calves per 100 cows (Table 6). The 1958 calf:
cow average is slightly lower than that of 1957, which was 42
calves per 100 cows. The counts, however,, are not directly
comparable, because the 1958 counts include relatively large
samples from two areas not represented in the 1957 counts •.
Productivity in the Upper Susitna and Copper River Valleys
varies-considerably from one local area to another and possibly
reflects the need for further investigation to delimit the boul).daries
of the local populations. The calf:cow ratios range from a high of
53 per 100 in the Oshetna Rivers and Tyone Creek area to a low
of 13 per 100 in the Kiana River and Lower Chugach Mts. area.
The sample from the latter area, however, is believed non-
representative of the entire population. Despite the non-uniform
rates of productivity the overall calf production appears good.
Survival
Survival as measured by the index provided by the ratio of
the 1957 bull calves compared to the 1958 young bulls is in excess
of 50 percent for the entire region (Table 4). Survival in the areas
accessible to hunters is reduced; Lake Louise and the Little Nelchina
areas had an indicated survival of 33 and 29 percent respectively.
Both of these areas are ~:.a.ccessibia~ to hunters and the population
boundaries are not well defined.
The low productivity and high survival rates of the Kiana
River and Lower Chugach Mts. area is believed to reflect a non-
representative sample. Inclement weather prevented adequate
coverage of the lowland portions of the area. Previous studies
have indicated that during October most of the bulls are usually
at or above timberline, whereas cows with calves frequent the
areas below timberline. The bull:cow ratio of 108. bulls per 100
cows also suggests disproportionate sampling.
In the areas where large samples were obtained, and where
hunting is limited to the areas along the few roads and numerous
lakes, approximately 60 percent of the 1957 bull calves survived.
Good examples of such.areas are the Alphabet Ridge, and Maclaren
River and Clearwater Creek areas where 1154 and 957 moose were
counted, respectively.
~21=
Effects of Hunting
The bull :cow ratio for the entire Upper Susitna and Copper
River Valley areas is 71:100, and compares favorably with the
same ratio for 1957 which was 69 bulls per 100 cows. The effects
of hunting are largely masked by combining the accessible areas
with those subjected to a lesser hunting pressure, and for this
reason several of the areas representing varying degrees of
hunting pressure are discussed separately below.
Lake Louise. Aerial hunting is intense in this area and
the bull:cow ratio is 62:100, as compared to last year's ratio of
49:100. It is believed that the small sample of 94 moose counted
in 1958 is probably non-representative of the existing bull :cow
ratio.
Maclaren River and Clearwater Creek Area. The bull:cow
.ratio in this popular hunting area is 45:100 and compares favorably
with the 1957 ratio of 43:100. The Maclaren and Clearwater areas
have been readily accessible to foot and swamp buggy hunters for
only three seasons. In 1956 the bull:cow ratio was 62:100, and initially
it was believed that the increased accessibility to hunting would
quickly lower the bull:cow ratio, however, much of the area is
closed to hunting and the effective radius of foot and swamp buggy
hunters is relatively small, considering the entire area. Hunter
success in 1958 was considered good, but it appears that the
hunter take may be approaching a plateau or maximum under the
present regulations and restricted accessibility.
If additional roads are constructed, or if the present road
system is maintained during the second season, when many of the
bulls inhabiting the Denali reserve move into the legal areas, the
annual harvest will definitely increase, and a further reduction of
the bull :cow ratio would be expected. · The reduction of the bull
population segment is not undesirable from a management stand-
point.
-The moose population inhabiting the Maclaren and Clearwater
areas are considered together this year because an early snowfall
had precipitated a movement of the moose from the highland areas
north of the Denali Highway to the lowland. areas between the con-
fluence of the Maclaren and Susitna Rivers. This altitudinal
migration was apparent during the counts and separation of the two
populations was impossible.
=22-
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Alphabet Ridge. Hunting, although intense in the access-
ible portions of this area is not reducing the bull population .
segment rapidly. The bull:cow ratio in 1957 andl958are Bland 68
per 100 respectively. The ratio indicates a reduction in the hull
population which may reflect increased hunting; however, the
1957 counts were believed to have sampled the sexes disproportion-
ately, in favor of males.
Oshetna and Little Nal:china Rivers. The bull:cow ratio for
this area in 1957 and 1958 is 78 and 67 respectively. Again the
1957 samples are believed to over-represent the bull population
segment. Hunting pressure in these areas, particularly; the
Little Nelchina River are is increasing, and a decrease in the
overall bull:cow ratio is expected. There are numerous airstrips
in this area, and the number of commercially operated swamp
buggies is increasing yearly.
Clarence Lake-Black River Area. No roads or trails
traverse this area and relatively few airplane hunters utilize
this moose population; the bull:cow ratio is 62:100.
Upper Gakona, Mount Drum and Wrangell Mts., and Kenai
River and Lower .CHugach Mts. All of these areas are relatively
inaccessible to hunters, except by airplane, and hunting does not
appear to be influencing the bull:cow ratios. The bull:cow ratios
for 1958 are 73, 140p and 108 per 100, respectively. The effects
of disproportionate sampling in the latter two areas were discussed
previously and are not elaborated on in this section.
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. A summation of the results of investigations to
determine the reliability of the counts was presented in the 1957
Federal Aid in Wildlife Restoration (Alaata) 12 {1): 15-16 report.
No new studies were conducted in 1958.
A knowledge of the range or identity of local or geographic
populations appears to be one of the most important criteria for
obtaining reliable composition counts. Some pbpulations are
defined particularly well, either by prominent terrain features
which act as a .barrier to movements of moose or through studies
of seasonal movements of moose. Other populations, such as
-23-
Table 7. Comparison of sex and age ratios in moose populations of Alaska.
Young Twin Calf Young
Total 13ulls--j ., Calves/ Percent . Young Bull Bulls/ ' .
Bulls/ lOQ:_frbtal Calves/ 100 Cows .· in Total Percent in 100 Bull Total Moose
Area 100 Cows Bull.s :.:~ :· 100 Cows w/Calf Herd . Total Herd Calves in Sample
Susitna -Matanuska Valley
1958 32 35 42 8 24 5 39 4294
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
1954* 63 --30 2 16 ----601
I 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
1950 16 . ' 1140 ----·-----'-· -.
Mean 41 26 42 7 22 5 40 2058.
Upper Susitna -Copper River Basin
1958 71 19 37 4 18 5 61 3781
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 83 26 52 10 22 8 80 1900
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Table 7. (Continued)
Young Twin Calf Young
Total Bulls/ Calves/ Percent Young Bull Bulls/
Bulls/ 100 Total Calves/ 100 Cows in Total Percent in 100 Bull Total Moose
Area 100 Cows Bulls 100 Cows w/Calf Herd Total Herd Calves in Sample
Kenai**
1958 44 21 42 15 23 5 43 3371
1957 43 18 35 12 20 4 45 3155
1956 51 13 24 10 14 4 54: 3786
1955 50 14 19 10 13 4 75 3109
1954 84 14 27 6 12 6 90 2048
I 1953 62 12 26 7 14 4 39 2900
l'V 1952 50 33 21 6 ~2 10 156 1136 \J'I
I
1951 69 18 23 16 12 7 108 1513
1950 --------7 ----1158
Mean 57 18 27 10 i4 6 76 2452
Tanana ValleY:**
1958 53 49 43 9 22 9 80 419
1957 6(} 32 42 2 20 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 81 35 46 7 20 9 107 316
* Limited sample may not be representative.
** Data from Refuge Supervisor Spencer.
*** Young bull-adult bull identification uncertain.
**** Does not include some areas as previous years.
those inhabiting the Mount Drum and Wrangell Mts., and Kiana
River-and Lower Chugach Mts. areas, are not well defined, and
much of the population data pertaining to these herds is inadequate.
The number of moose counted per hour of aerial, counting
time has been used as an index to relative moose density, and as
a check on the reliability of the aerial counts. The data is
presented in Tables 2 and 6. The overall moose per hour of
counting figure for the Lower Susitna and Matanuska Valley areas
for 1957 and 1958 was 123 and 150 respectively. The increase
in the number of moose counted in 1958 is believed to refle-ct
the good survival of moose during the 1957-58 winter, and to the
better_· counting conditions in 1958. In 1957 the counts, in some
areas were hampered by poor snow cover. The moose per hour
figure -in the Upper Susitna and_ Copper River Valleys in 1957 and
1958 were 102 and 106 respectively. Counting conditions were
approximately identical both years. A summation of moose sex
and age composition surveys conducted in Alaska from-1950
through 1958 is presented in Table 7.
RECOMMENDATIONS
The results of the 1958 sex aind age composition counts
suggest the following recommendations.
1. Sex and age composition counts should be continued.
The sample size could probably be reduced if the counts
were made when the moose are more homogeneously
distributed during the rut--in late September and early
October.
2. Survival of moose to 12 months should be measured by
spring calf:cow counts made in late May and early June.
Prepared by:
Robert A. Rausch
Wildlife Management Biologist
Date: January 31 ~ H59
Approved by:
Sigurd T. Olson
Acting Supervisor of Game
Restoration
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i JOJ3 NO. 2--Moose Calving Studies.
PERIOD COVERED: May 1, 1958, to July 1, 1958.
ABSTRACT
Aerial counts of moose inhabiting calving areas are most
successful in the early morning, between 3 a.m. and 7 a.m.
Pregnant moose seek a variety of vegetation types for calving,'
but apparently concentrate in lowland, marshy areas that provide
a variety of early-spring food and escape cover.
Moose calves first were seen on May 11, in 1958. Calving
progressed rapidly and peaked on May 25 or 26. The final crop·,
estimated from aerial counts and from in utero observations, was
109 calves per 100 cows of Age Class I or older(24 months or older
at the time of the parturition counts).
Twins occur in about 30 percent of the pregnandes, and
two sets of triplets were observed.
Aerial counts made when the calves were about six months
old revealed a calf mortality of 45 to 60 percent. Mortality ap-
proximating this magnitude has been relatively constant in the
Valley areas for a number of years and may be normal under the
environmental conditions existing on the study areas. Survival of
twins varies considerably from area to area. Specific factors
affecting overall calf survival and survival of twins are not known.
OBJECTIVES
To determine the areas, pattern and dates of moose partu-
rition, initial productivity and calf survival.
TECHNIQUES USED
This project attempts to assess some of the problems
seemingly inherent to aerial calf:cow observations rna de in the
spring; and to determine the calving areas, the progression and
magnitude of calving, and calf survival.
-27-
Eleven periodic counts were made on moose calving be-
tween May 7 and June 17, 1958. The counts were made with a
supercub, piloted by Division of Predator Control assistant
district supervisor Burkholder, and Aircraft Division pilots
Smith and Wardleigh. The observer was P.R. Biologist Rausch.
A total of 40 hours of flight time was expended on this project.
FINDINGS
Several problems encountered in making aerial observa-
tions of moose calving were discussed in the 1957 Federal Aid,
Alaska, 12( 1): .60 report •. The problem believed most critical
to making accurate parturition~cow observations was the tendency
for some cows to hide their calves, and the failure of these cows
to exhibit a response pattern to aerial buzzing that would enable
the observer to determine the presence or absence of a calf.
The term parturitio.n:cow ratio as used in this report
refers to the number of cows that have given birth at the time of
the aerial counts. The term is more exact than a calf:cow ratio,
because moose frequently have twins. Thus,. a calf:cow ratio
would over estimate the incidence of calving.
I
The counts made in 1958 attemptetl to assess the problem
of 11 questionable cows 11 (those cows that appear and respond as if.
a calf is :present although not visible to the observer), by making
the counts in early morning, by continuous circling of question-
able cows, and by consideration of the cowsw physical appearance.
The counts usually were started at dawn, 3 a.m. and were
completed approximately four hours later. The early morning
counts s.~em to coincide with the activity periods of the moose
inhabiting the study areas, as most moose observed were stand-
ing and feeding. Flying conditions are generally better in the
early morning. Turbulence was seldom encountered, and light
intensity was increasing, whereas light intensity was decreasing
during 1957 evening flights. Counts made during midday are
unsuccessful, bec.ause most moose are lying down a..n:d are
:partic;u,larly difficult to see.
Animals responding in a manner that indicated a calf was
possibly present were circled repeatedly at low elevation until
the calf was seen, or the observer was satisfied that no calf was
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present. Frequently, particUlarly in June when some of the calves
were several weeks old, the calf was not seen until the fourth or
fifth pass. Some of the calves were located several hundred yards
from the cow. Again, these calves appeared to be the older q.nimals;
newborn calves generally were found·close to the C()W.
The physical appearance of pregnant cows and those that have
given birth is quite different. The difference is readily apparent. if
the observer obtains a dorsal. view of the animal. The abdomen of
pregnant cows is qu:ite obviously nround" in May. Weights of a few
complete uteri collected from pregnant cows in April and May ranged
from 100 to 175 pounds, and equalled 12 to 20 percent of the animals
total weight. Thus, the reasons for the difference in dorsal profiles
is obvious. The physical appearance of cows suckling young apparent~
ly deteriorates rapidly. Their ribs become prominent and their coats
ragged, often large patches of hair are shed. Other moose seldom
exhibit "patchy" shedding in early June. The non-pregnant two-year~
olds frequently retain a glossy, dark coat of hair until mid-June.
The combination of early-morning counts, persistent circling
of questionable cows, and evaluation of the cows' physical appear-
ance reduced the questionable cow segment considerably in 1958.
The questionable cow category did, however, increase on the June
counts( Tables 1 and 2). The reasons for this increase a:r:e not
known~ but probably include the following: the previously discussed
increasing independence of the older calves, the emerging leaves
and grasses which form complete canopies in some v·egetation types,
and the probability of early-calf-mortality. The latter seems the
most important factor, although a diffi.c.ult':one to quantitate. Cows,
seen in early June, that act and look as if they have given birth,
but that have no apparent calf coUld be cows that have lost their
calves. Calf mortality from May to November is high (see Calf
Survival), and it is logical to assume that some calf mortality occurs
during and and immediately following the calving period. It is not
known how long a cow will frequent an area where she has lost a
calf, or how long she will act as if she has a calfo Unfortunately,.
sp-eciffc·mortalitYfaCtors affecting calf moose are not well known
(see Calf Survival). Continued refinement of present counting
techniques should provide adequate data on the progression and
peak of calving. Counts of moose calves beyond mid-June may not
be practical until knowledge of specific mortality factors is gained.
-29-
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Table 1. Summation of Aerial Surveys on the Progress of Calving in the Lower Susitna and
Matanuska Valley Moose Populations.,;=May and June 1958.
female female female female female total short
without status with with with total cows & yearlings
total
all
Date calf unknown 1 calf 2 calves . 3 .calves fern ales calves calves (11 to 12mo.) anirmls
May 7
May 9
May 12
May 16
May 19
May 21
May 24
May 27
June 3
June 5
June 17
,.,..---
!
60
85
166
107
91
78
53
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16
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6
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0
1
1
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10
8
10
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0 0 0 60
0 0 0 85
0 1 0 167
4 0 0 112
3 6 0 101
18 10 0 106
25 '8 0 87
32 27 0 79
44 14 1 85
33 11 0 61
7 7 1 30
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0 60 31 91
0 8.5 25 110
2 169 67 236
10 1~2 61 183
15 116 40 156
38 144 53 197
41 128 41 169
86 165 32 197
75 160 25 185
56 117
21 51
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Table 2. Progress of calving in the Lower Susitna and Matanuska
valleys as indicated by the various parturition:cow ratios.
Observed *Estimated **Twins: Total
Parturitions: Parturitions: Calves: 100 partu-cows in
Date 100 cows 160 cows 100 cows i:itio.ns sam_ele
May 7 0 0 0 0 60
May 9 0 0 0 0 85
May 12 • 5 • 5 • 5 --167
May 16 3. 5 4.0 3. 5 () 112
May 19 9. 0 10.0 15.0 66. 6. 101
May 21 26.0 26.0 35.8 35.7 106
May 24 37. 9 39.0 47. 1 . 24.2 87
May 27 74.6 81.0 108.8 45.7 79
June 3 69.4 81. 1 88.2 25.4 85
June 5 72. 1 85. 2 90. 1 25.0 61
June 17 48.3*** 80.6 77.3 53.0 31
* Computed by including unknown status females as having calves.
** Triplets included in twin:singleton ratio as twins.
**)!< Count not completed due to adverse weather.
-31-
Calving· Areas.
Cows about to give birth. seek a variety of habitat types.
Certain vegetation types or .communities, however, appear to
attract relatively large numbers of moose. The types of vegeta-
. tion vary widely, but all possess several common features.
The calving areas illustrated in Figure 1 have an abundance of
. early-spring-vegetation. Some of the more common varieties
are sedge, calamagrostis, pond weed, various grasses, includ-
ing salt grass in some instances, and aquatic species, such as
pond lily.. The areas are either open or have a number of open-
ings. Many of them have dense borders of alder, birch, or
willow. If the areas are extensive and are not broken into a
patch-work of bordered openings, then clumps of spruce or
alder are usually interspersed throughout. The areas are wet;
frequently new born calves have been observed standing belly-
deep in near freezing water.
Not all moose calves are born in areas similar to those
described above. Newborn moose calves have been observed in
mature Birch-Spruce forests, and well above timberline on
Willow mountain. The only known concentration. areas, however,
occur in the lowland areas shown in. Figure 1 ..
Aerial observations of actual parturition were made on
six occasions. The areas chosen showed no consistent pattern.
Most of the cows were in brush or marsh areas and the ground
was water soaked. Much evidence of trampling was evident, and
small willows and alders were broken ..
The factors making the calving concentration areas a~ctive
to:moose are not known~ However, the soft, quagmire underfooting
could give the long legged moos.e an advantage over certain preda=
tors, and the early-spring vegetation provides a lush diet at a
critical period.
Progression of Calving.
To determine the pattern of calving activity, periodic
parturition:cow counts were made from the air. Flights began on
May 7, and calves first were sighted on May 12, when a count of
166 cows revealed one cow with twins. A minimum of 100 cows
were tallied on each count from May 12 through May 21, when the
removal of over 20 calves from one of the principal parturition
-32-
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Figure 1. Moose calving-concentration-areas in the Lower Susitna Valley.
~1111111111/lt~
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'(; $\
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Scale:
20 Miles
Key:
Calving Areas
1. Hay; Elats
2 .. Goose Bay
3. Salt Flats
4. Lake Nancy
5., Willow
6. Kashwitna
cool.<. 1~1-a~'t
-33-
areas for a stocking project eliminated this area from the partu-
rition counts.
Figure 2 presents a graphicall.nterp~etation of the data
obtained, illustrating the approximate progression of calving ..
Figure 3 presents the estimated progression of calving~ with
the questionable cows included with the cows with calves segment
of the population. Figure 4 depicts the peak of c·alving as re.veal-
ed by plotting the daily partUrition increments· derived. f'ronJ. th.e
curve in Figure 2. All curves are fitted visually and follow the
technique de_scribed by R. 0. Skoog in the 1958 Federal Aid,
Alaska 12{3) ~56~70 report. Moose calving progressed rapidly
and probably reached a peak on May 25 or 26. The present
parturitio-n. data are not complete a:nd more parturition count is
would probably estabHshthe progression and peak of calving
more accurately. The present data of progression.and peak~
however, seem logical when compared to the observations on
moose productivity reported in the 1958, Federal Aid, Alaska
12(1) :56-109 report.
Magnitude of Ca,lving.
A final calf count was impossible because of adverse
weather, and because of the previously discussed counting
difficulties encountered in mid-J.une. An estimate of the calf
crop is made 9 however, based on the parturition counts made
in early June,. and on the in utero observations made on some
·~-~-100 cows collected in the study areas from 1956 to 1959. The
estimat~d parturition~cow ratio on June 3 and 5. Table 2 and
. Figure 3. indicated 80 to 85 parturitions per 100 cows. The.!!!
utero examinations r.evealed that 95 percent of all females old~r
'than 24 months were pregnant. The observers making the partu-
rition counts, however, cannot distinguish the non-reproducing
. Class! cows(l2~24 months) from older cows, and this neces ..
sitated an estimate of the percent Class 1.· cows in the female
population segment. Limited population age composition data
from 1956. showed that Class I females comprised only 6 per-
<eent of the female segmento A favorable winter in 1956 and 1957,
the winter when the 1958 Class I individuals were· fetuses and
ccalwes, respectively,. suggest that the 1958· Clas·s I segment is
probably larger than that of 1956. An arbitrary value of 12 per-
cent, doubling the 1956 figure~ was assigned to the 1958 partu-
rition count data (Table 3). Thus, of every 100 cows counted
in 1958, 88 were potentially pregnant~. and 84 or 95 percent of
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and June 1958 of Lower Susitna and Matanuska
Valley moose populations.
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probably non~representative.
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Lower Susitna and Matanuska Valley moose populations in May & June of 1:958 •
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these were considered pr-egnant (Table 3). The average of the
twin:singleton ratio from May 21 to June 3 indicates 31. sets of
twins per 100 parturitions; in utero data, collected over a three
year period indicates 27 s-ets. For convenience of computation
an arbitrary value of 30 sets of twins per lOO parturitions was
assigned to the calf crop data .(Table 4). Thus, the £ina~ esti-
mated calf crop in 1958 was 109 calves per 100 cows, including
the Glass I individuals.
Survival.
Calf moose mortality-, from birth to six months, of 45
to 60 percent in the areas studied may be nprmal for the species
under the existing environmental conditions .. Th~ adjusted calf
crop, based on parturition counts and in utero examinations, is
estimated to be 91 calves per 100 total cows, including the short
yearlings, 11 to 12 months old at the time of parturition counts,
as cows (Table 3). Aerial sex_and.age counts made in October
and November of 1958 when the ·ealves=of-the=year were five to
six months old revealed an over-all calf:cow ratio of 42 per 100,
and indicates a calf mortality of 53 percent.
Table 3 presents the estimated initial calf production. and
survival of three local, contiguous moose herds, Matanuska
Valley,. Willow and Kashwitna.-The initial production figures are
based on data presented in the section on Magnitude of Calving,
and calf production is assumed to be similar in all three areas.
The fall calf:cow ratios were obtained from aerial sex and age
composition counts made in October and November, 1958. These
counts indicate a calf mortality of 48, 54 ari.d 61 percent in the
Matanuska. Valley, Willow, and Kashwitna areas, respectively.
Table 4 presents an estimation of calf mortality from
parturition. to six months in three local areas. The data is based
on a theoretical sample of 100 ·pregnant cows, which give birth
to 130 calves (see Magnitude of Calving). Mortality of calves is
measured by the fall sex an:d age counts. These counts reveal
that both twins seldom sur-vive to· six months. Mortality of one
twin ranged_ from 88 percent in the Matanuska Valley to 82 percent
in.the Kashwitna area. In an effort to measure the relative
survival of singletons and. "the twin rema iniri.g" with that of both
twins, the known instances in which one of twins died were sub-
tracted from the total known mortality~ The remaining mortality
was assigned equally to singletons and·"the remaining twin''(Table 4.
-39-
Table 4. Estimated mortality of calf moose in three local areas in. South Central Alaska, 1958.
Calves · Dead calves Percent
produced Percent Known Known fr. singleton mortality
by 100 ,. N() •. No. mortality Percent* No. No. .andre-singletons &
pregnant single sets all m0rtality twins dead maini:ng remaining
Area cows births twins calves twins dead calves twins twins·
Matanuska
Valley 130 70 30 48 88 26 62 36 '38
. Willow 130 . 70 30 54 85 . 26 70 44 .46
t Kashwitna 130 70 30 61 82. 25 79 54 57
I
* Mortality of at least one of twins.
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For exa.mple=~in the Matanuska Valley 100 cows produced 130
cal yes, comprised of 30 sets of twins and 70 singletons. .A,er ial
counts six months later, in November, revealed a calf mortality
of 48 percent and twin mortality of 88 percent. Thus, of the
original 130 calves 62 had died, and of the original 30 sets of
twins 26 had lost at least one. In computing the percent mortality
of singletons and the remaining twin the 26 known dead twins are
subtracted from the known loss of 62, leaving 36 unaccounted
dead calves which must have come from the 70 singletons and
26 "remaining twins". Thus, singletons and 11 remaining twinsn
in the Matanuska Valley suffered 38 percent mortality. The 26
"remaining twins" had a mortality of 38 percent or 10 calves
and the 30 original sets had a mortality of 8 8 percent or 26
.calves. Thus, of the original 30 sets of twins or 60 calves 36
or 60 percent died as compared to 26 or 38 percent of the 70
singletons. Cows giving birth to twins reared • 8 calves per
cow; cows giving birth to singletons reared. 6 calves per .cow.
Mortality of twins in the Willow and Kashwitna areas was
similar to that of the Matanuska Valley; mortality of singletons
and 11the remaining twin'\ however, was somewhat greater. The
reasons for the apparent variations in survival of calves from
area to area are n.ot known, but possibly reflect differences in
local environmental conditions.
RECOMMENDATIONS
The parturition counts should be continued for at least one
more year to more accurately determ ine the progression and
peak of calving. Larger periodic samples, preferably between
150 and 2.00 cows each, ar~ desirable.
A study to determine and quantitate the factors affecting
survival of moose calves should be inaugurated.
Prepared by~
Robert A. Rausch
. Wildlife Management Biologist
Date: January 31, 1959
Approved by:
Sigurd T. Olson
Acting Supervisor of Game
Resto ration
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JOB NO. 3==Distribution, Movements, and Dynamics of
Railbelt Moose Populations.
PERIOD COVERED: July 1, 1958, to June 30, 1959.
OBJECTIVES
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 the factors
affecting them.
To obtain data on reproduction, mortality and age
structure as a basis for interpreting the dynamics of these
populations.
TECHNIQUES USED AND FIND~NGS
No work was done on this project. The scheduled end of
Federal Aid in Game Restoration as a function of the U. S. Fish
and Wildlife Service on June 30, 1959, necessitated a curtail-
ment of field activities, and this project was dropped.
Prepared by~
Robert A. Rausch
Wildlife Management Biologist
Date: April ]. 7, 19 59
Approved by:
Sigurd T. Olson
Acting Supervisor of Game
Restoration
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JOB NOo 4~ Herd Compositi~ in Iilte-ri.or klaska
'' PERIOD COVERED: October 15· to December 6a 1958
ABSTRACT
Aerial composition counts were conducted during November and
December in the Tanana, Fortymile., and. lower Koyukuk Valleys. Eleven
hundred nine moose were· tallied in 19.,3 hours of aerial counting for
an average of 57.,4 moose per hour.,
Productivity indicated by calf: cow ratios, twins per 100 cows
and the calf percent of the total herd remains ngood" in all three
areaso
Survival of moose to the yearling stage in the Tanana and Forty-
mile areas is higher than that observed in the Koyukuk,.
The effects of hunting in all three areas has little effect on
the moose populations as a wholeo HuntiD.g pressure is quite localized
in all three areas 3 since access is limited to those areas immediately.
adjacent to the roads and rivers.,
There is still a decided need fo~ study to provide data which
will enable the investigator to better evaluate the effect of the many
variables affecting composition counts from year to year.,
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 predationo
TECHNIQUES USED
Aerial composition counts were conducted in the Tanana Valley in
the following areasz Salchaket Slough, Chena River, Chatanika River,
Shaw Creek and Goodpaster Rivero The Mosquito Fork-Kechumstuek Flats
were i.nc·luded in the Fortymile counts., Only the flats immediately ad-
jacent to the river between the villages of Hughes and Koyukuk 'station
were included iri the Koyukuk counts ... Coverage was th~refore similar to .
1957 with one exception; severe i;iurbulence caused by high winds draining
out of the hills prevented aerial counting along any of the 'tributaries
of the Koyukuk Rivero (See FederaJ. Aid Job Completion Report -Vol., 12,
Noo lo PPo 1229 123 9 124, Figo 1,2, and .3o)
The counts were accomplished using a tri-pacer in the Tanana
Valley.~> a super-cub in the Fortymile3 and .a Cessna 180 in the Koyukuk
area.. The aircraft ~ere flown at altitudes varying from 500-700 feet
above the ground while countingo MOose were tallied in the following
categories&
=43=
#
lo Young bulls ... antlers' spiked or forked wi~h little or no
palmationo There is probably some overlap between this
class and the adult class. These moose are considered as
"yearlings". (17-18 months)
2. Adult l::ulls -antlers with decided palmation ranging small
to large.
3o Cows -all antlerless moose including yearlingso
4 o Calves -young of the year (5-6 months).
5o · Unidentified -moose which could not be classified due to
poor visibility or fzying conditions o
The Tanana Valle.y survey was conducted October 27-28 by Wilbur J.
Libby of the Alaska Department of Fish and Game as part of a program
designed to acquaint state personnel with the current Federal Aid programo
It will also serve to establish continuity of activity during that period
when the Bureau of Sportsfish and Wildlife relinquishes its responsibilities
in the Federal. Aid program to the State of Alaskao Counts were conducted
in the Fortymile on November 25 by personnel from the Tok Stationo · Jack
Frost, Game Management Agent,and Art Brazda, District Agent, acting as
observer and pilot, respectivelyo The counts in the Koyukuk area were
accomplished December 4-5 by personnel fran the Fairbanks Statio:llo Sig
Olson, Wildlife Management Biologist, and Joe Miner, District Agent, were
observer and pilot.
Techniques of counting and analysis of data were similar to those
employed in previous yeam <ani will not be reiterated here. The data were
analyzed to determine current productivity, survival and effects of hunt-
ing using the same principles and methods described in the 1957 Job
Completion Report (Moose Managem.e~t Studies~ Project W-3-R-12, Work Plan
A, Jobs Noo 1 and 6, Volo 12, Apr~l 1, 1958Jo
The areas involved in the Tanana Valley include several separate
drainages into the Tanana River, however, they are fairly contigu.ous and
it is believed that the moose populations are not clearly identifiable
with the possible exception of the Salehaket area.
The Fortymile area is considered as a single unit in the area .
covered. There is an indication that composition varies within the moose
population along the Koyukuk Rivero Experience, however, is too limited
to divide this· area into separate populations., Counts are presented
currently, however, from three areas along the lower Kc~ since the
composition in each of these areas was different~ particularly with
reference to the male component of the populationo Overall evaluation
for each area, however, has been based on the weighted averages for the
entire area in each in each case.
. The field data for this study are in the files of the Federal Aid
to Wildlife Restoration Office at Fairbankso
-44-
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FINDINGS
A summary of the composition counts obtained from: the moose popula-
tions in the Tanana, Fortymile and Koyukuk river vaiieys is presented in
Table 1. The composition o£ the moose pOpulations in e~ch of the areas
are expressed as sex and age. ratios in Table 2. Table .3_:presents a com-
parison of these ratios for the past threeyears ·(1956;:195,7 and 1958).
The comparison of the current young bull: cow ratio expressed as an index
to calf survival is presented for each area in Tabf.e 4• ·· .·
In general,. circumstances were very favorable for .conducting herd
composition counts during the fall of 1958. The snow cover was complete,
and with the exception of"areas of local turbulence, flying conditions
were goodQ The total flying time expended during the survey was 28.2 hours
with 19o3 hours spent actually counting mooseo The total number of moose
seen per flying hour was 57 o4; 26o 7 moore moose per hour than observed in
1957o The actual numberoof moose seen per hour by area·var.ied from .36 in
the Tanana Valley to 1.31.6 in the Koyukuk River areao !comparison of the
moose seen per hour for 1957 and 1958 is presented in Tabie 5. ·
Table 5o Comparison of moose seen per hour in the Tanana;. Fortymile and
Koyukuk Vallezs·-12~7 vs .. 12~8
TOTAL NO;. NOo HOURS .. " .. NO. ~MOOSE SEEN
AREA MOOSE SEEN FLOWN PER HOUR·
1257 1958 1.2.21 1258 J:.221. ~
Tanana 242 427 9 .. 8 llo8 24o7· .36oO
Fortymile 141 129 3o5 . 3 • .3 40o0 .39~1
Koyukuk 226 553 ·6o2 4o2 34c.6• .. 13lc.6
.. -
TOTALS 609_ 1102 19 .. 8 12·2 30o7 _57 o4
The number of moose seen per hour in 1958 increas-ed. 31 percent in the
Tanana Valley.. remained almost the same in the. Fortymile and increased
302 percent in the Koyukuk~ In 1957 snow cover was only partial in the
Tanana Valley and temperatures ranged from zero to ·2oO F. · In 1.958 complete
snow cover and temperatures ranging downward from zero to -200 F. improved
sighting conditions and undoubtedly increased the number of moose seen per
hour.. Sighting conditions in the Fortymile area were a~st exactly the
same in 1957 and 1958 and the similarity in counts 'for both years is under-
-standab1eo In the Koyukuk Valley~ partial snow cover.!) high winds, and lack
of good light restricted visibi~ity to a great extent in 1957. In 1958,
two to three feet of snow and excellept visib~ty ·improved sighting con-
ditions inuneasurablyo It was also apparent that there were relatively few
moose in the hills bordering the rivero Nearly all· moose were found in the
willow flats adjacent to the river~ perhaps as a result of deeper snowo
Greater familiarity with the area may have also influenced the count
favorableo Although there is no readily available yard stick to measure
the actual increase in this area, herd composition data !rom 1957 indicates
population densities in the Koyukuk are increasingo All the above reasons
have contributed in part to the spectacular increase in the number of moose
seen per hour in this areao
-45-
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Table 1. Swmna.ry of Moose Populatio~ Composition Counts.-Ta.nana":V:all.ey; FOrt.~.,~-.and.Xo~V:alleys.
, October 27, 1958 -December 6 ,_._1958 ____ , ..... _ ........... · _ ... __ .. _ ..
'.
AREA
TANANA VAlLEY
Chena R.-Chatanika R.,
Shaw c., Salcha R.,
Goodpaster R.
Tanana River
(Salchaket)
~f.bove areas
FORTIMILE
Kechumstuk and
Mosquito Fork
KOYUKUK
Hughes to Hog River
Dalke River to Katee1
Katee1 R. to Koyukuk Sta •.
' < I
Above Areas Combined
GRAND TOTAL
r----'1 I ·-.~ ' I' -' :
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· MAL E ..
rnTTl\Tr.._ ADIJLT .TOTAl
-
16
21
37
14
12
13
10 I
35
86
:----""'
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. 45
31
76 '
'
25
33
25
21
79
180
.....----,
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....
61
~
52 ..
11..3'.
39
45
38
31
114
266
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~OOSE
TarAL rr~AL r.rnm. ~ _ F iM·A·L·E· ·_·_·. ·. rr-orAL _ IDM ~~[l) .. ~Ol'~. r W/0 W7I 1/;4 TU.l'JU. (}ALVES MOOSE~ MoOSE_ MoOSE bBS •. OUR
-· ·-'-' . -' I ' -: -. -·
.
67 44-3 . I 114 50 225 .8 233 9.0 26
61 32 5 98-42 192 :2 :194-2~8 69
' 128 76 a. 212 .. 92 417 .. 10 i:4Z7 u .. s 36
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36 24-2 62 28. 129 0 .129 '3.3 39
;' 32 19 4-55; 27 127' 3 130 1.1 P-l-8
(
87 59 16 162. 91 291 2"-._;I 314 .. -2.0 ~57
22 .. 2.0 3 ·45 -26 102. 7 10.9 1.1 99
I
I
141. 98 2.3 262. 144--· .. 520. 33 553 4 •. 2 132
305 0.98 33 536 264 1066. 46 1109 19.,3 57.4
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Table 2o Sex and Age Ratios = Tanana .. Valley, Fortymile, and.. .. Koy;u.kuk V<;UJ.ey. 195$. ·
TOTAL YOUNG CALVES ~ . CALF YChBULL YGo BULL YGo BULL
BULLS BULLS PER CALVES ~·OF. %OF PEl PER
PER PER 100 100 ~~:~·· ~OTAL, . TOTAL 100 BULL 100 TarAL
AREA cows . AD. BULLS ·COWS :IERD . HEF..D.·. I CALVES. COWs MOOSE
'' -
TANANA
Chena Ro, Chatariika R.
Salcha, Shaw Cr o, and
Goodpaster Ro · ' 53 37 44 6 22 7 61._ 14 227
!;
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Tanana Valley
(Salchaket) 53 67 43 14-22 11 100 21 192
Above areas combined 53 49 43 9· 22 9 80 17 419
FORTYMILE
Kechwnstuck and '
Mosquito Fork 63 56 45 ·a -22 11 '100 ' .. 23 129 ..
KOYUKUK R., .,
Hughes to Hog River 82 36 49 ,17 21. ·9 92 22 127
Dalke River to '
...
Kateel R. 23 52 56 21. 3L 4 29 8 291
Kateel R. to Mouth
of Koyukuk 69 48 58 1:3 25-10. 7? 2~ 102
Above ar~as combined 44. 44 55 19 28 7 49 13 520
Table 3G Comparison of SeJ,C a~tcl. Age.Ratios. in.MoosePQpuJ.a."t.:i.oJ;UL:j..rl, IJ;lt~riqr, . .A:J.al?ka _ .. _
AREA
Tanana yalley
J-Fortymile
f
. Koyukuk
..., r----""1 r-----: n-:-: I
1958
1957
1956
1958
1957
1956
1958
1957
1956
TOTAL IOUNG .
.BULLS , BuJ..Is
PER PER.lOO
100 co~~ An.· Butts
53
60
83
63
91
66
49
32
25
56
29
30
CALVES TWIN. _ CALF
.PER CALVJ$5 % _-OF
l.OO ... 10-0~ C9¥S _ . Tor AL.
COVlS 1-J/CALVES HEPJJ.
43
42
47
45
46
53
9
2
5
8
8
0
22
20
20
22.
19
24-
44 44 55 . 19
23
28.
28 00 '25 66
NO DATA.AVAILAl3LE
YG.BULL YG.-.Bm:.t YG.BULL TOTAL
% OF -. 'PER . . PEa MOOSE
. TQ!.' At .. l.QO. ~~ _ ... :WO -~
.' HERD CALVES-CO""lS SAMPLE
9
7
7
11
8
7
7
6
~~~--~--~
80
69
71
100
89
60
-49
48
17
15
16
?3
2.0
15
t.3
16
419
236
405
~9
140
129
520
216
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Table 4. Index to the Survival of Bull Calves to 18 Months
Bull Calves Young Bulls
per per
100 eows 100 Cows Indicated
AREA 1957 1958 % ·Bu:rvival
TANANA
Chena, Chatanika,
Salc~a, Shaw
Goodpaster 22 14 64
Salcha.ket 18 21 100
Above combined 21 17 81
FORTYMILE 23 23' 100
KOYUKUK 27 13 48
-49-
It is very evident that several variable factors influence the
number of moose seen per unit of effort.. Insufficient data are presently
on hand to properly evaluate the. precise effect. any one or combination
of these might have on the final results., When and if' real values for
these factors can be applied to the counts, the numbers of moose seen
per hour will become a more realistic index to trends in moose population
densities from one year to another.
Productivity
Tanana Valley -Productivity in the Tanana Valley continues to be
"good".. The calf:cow ratio of 43:100 has changed only slightly from 1956
and 1957 (47:100, 42:100, respectively)., Nine sets of twins per 100 cows
with calves is another indication of satisfactory reproduction.. Th~s is
the highest twin ratio recorded since 1955 when the ratio was 13:100.,
Calves comprised 22 percent of the total herd.. During the past three years
this percentage has been quite. constant ranging between 19 and 22 percent.
Fortymile -The l~vel of productivity showed little change from
previous years and is rated "good". The calf: cow ratio of 45:100 was only
one calf less than in 1957. The number of twin calves per hundred cows
with calves was 8:100 and did not change from the previous year. The per-
cent of calves in the total herd increased slightly over· 1957 (19 percent
in 1957 to 22 percent in 1958). This could reflect the reduced bull count
however, since only 63 btllls per 100 cows were observed in 1958 as compared
to 91 per 100 cows in 195,7.
Koyukuk-Productivity continues to be "excellent" in this popula-
tion despite the downward trend from 1957. The combined and weighted
average calf:cow ratio for the entire area declined from 66:100 to 55:100.
The incidence of twin calves per 100 cows with calves declined from 23
to 19 and perhaps is a secondary indicator of a downward trend in produc-
tivity.. The twin calf ratio, however, still remains perhaps the highest
of any population presently under observation., It is possible that .the .
factors governing survival are more favorable in this area than elsewhere,
resulting in better calf survival. The fact remains, nevertheless, that
the overaJ.lrate of calf production is better than in other areas ..
Productivity varied somewhat from one se@Ilent of the river to
another.. Between Hughes and Hog River, the calf:eow ratio was 49:100 as
compared to 56:100 ·in the area between the Dalke and Kateel Rivers and
58:100 from the Kateel River to Koyukuk Station., The ratio of twin calves
per 100 cows with calves were 17,-2.1, and 13, respectively.. Generally,
the variation in productivity indic:es is not significant enough to cause
concern, since the rate is rr good" or "excellent" in all areas.,
The percentage of caJ.ves in. the total herd for the entire area (28%)
remained the same as that for 1957., This is the highest percentage of
calves obtained in any area thus far. Although this figure depends on.
changes in the composition of the herd from year to year, it provides a
general indication of the annual increment of young animals.
-50-
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Survival
Tanana Valley :-The survival of calves.to the yearling (18 months)
stage is good in the Tanana Valley-. T~e ratio Qf young bulls to . bull
calves is 80:100, 11 percent higher than in 1956. The index to survival
of bull calves to 18 months (based on the comparison of the ratio of bull
calves:l.OO cows in 1957 to <the young bul:Ucow ratio iil 1958), $hows that
81 percent of the bull calves survived, a. figure· similar to the ratio of
young bulls to bull calves in 1958.. No index to survival of females to
the :Yearling stage has been develonedo howevero it can be assumed that
since females ar; not hunted that ;urrlval was-: equal to or better .than that
for maleso · · ·
. Fortzmile -The ratio of bull calves to cows in i957 and ,the ratio of
young bulls to cows in 1958 are the same (23:100). Similarly .I' the ratio
of yearling bulls to bull calves in 1958 :ls l.OO~lOOo This suggests bias
in sampling since it is assumed that if the calf crop 1.s unifol;'m from year
to year the young bull mortality should become apparent after a years'
timeo The extent of the error cannot, however, be evaluatedo One thing
is very evident.\) the incidence of young bulls in this moose population is
very high indicating excellent SUrviValo .
Koyu1mk ~ The survival index.11 based on the comparison of the previous
yearsn bull ,calf:lOO cow ratio with the current year 8 s young bull:lOO ·
cow.s ratio (Table .3), indicates that 48 percent of the bull calves six
months of age survived to be 1.8 months of age., The young bull:bull calf
ratio of 49:100 indicates a similar level of survivalo The latter ratio
is almost the same as in 1957 (48=100).. This is the lowest survival level
shown for a:ny of the interior moose populations Un.der observation. Hunt-
ing, predations and weathe,r are all contributing factors to the compara-
tively law survival rate, but to what extent each one, or a combination of
them are responsible, is unknown ..
Effects of Hunting
. . Tanana Valley -The comparatively high bull;·cow ratio continues to
reflect the relatively inconsequential effects of huntingo The ratio for
the entire area decreased from 60 bulls:lOO cows in 1957 to 53:100 in 1958.
This may be the result of the very successful current hunting season, a
disproportionate sampl.ing of bulls or both.. The patterns o£ hunting do
not vary significantly from year to year in the Tanana areao All hunting
is accomplished by boat and cari therefore, onl.y those areas immediately
adjacent to the routes of travel are hunted leaving the areas away from
roads and navigable waterways almost untouched.. The ratio of bulls per 100
cows decreased from 68:100 to 53:100 in the tributary areas and increased
from 44:100 to 53gl00 in the Salchaket area.. This suggests errors in
counting rather than a significant change due to hunting ..
Fort:vmile -The ratio of bulls to oows was 63:100 in 1958 as com-·
pared to 91~100 in 1957 and 66:100 in 1956o The difference in sex ratios
from year to year is probably the result of errors or bias in counting
rather than actual changes brought about by mortality or other factors
acting positively or negativelyo Hunting has little influence on this
-51=
population. The kill occurs largely during the latter half of September .
and only those areas iJmnediately.adjacent to the Taylor Highway are
affected. · ·· -·
KoyukUk -The ratio ~f bulls to cows for the entire area dropped
from 80:100 in 1957 to 44:100 in 1958. The extreme difference in the two
years is remarkable. The decline is vecy probably: due to differences in
conditions under which tne counts were conducted each year rather than
mortality factor. Differential sex distribution could effectively dis~ort
the bull; cow ratio~ It is interesting to note that the bull: cow ratio be-
tween Hughes and Hog River was ,82:100 and from the Kateel River to Koyukuk
Station was 69:100. These ratios are more in line with that obtained in
1957. The middle portion of-the area between the two aforementioned areas
(Kateel.River to the Dalke River), however, produced a bull:cow ratio
23:100. Why the decided va;riation in this one particular area exists is
not understood;. It may be: the result of a difference in -sex distribution
due to prevailing weather conditions at this time of the year.. The fact
that the upp·er ana J()'lrfer. areas have !itf1er:. h~ls or mountains adjacent to
the river while the _c,nter area consJ.Ste ehtJ.rely of flats may have some
effect on sex distr:ib~tion~ .· Hunting pr~ssb.re is probably greatest on the
upper and lower sectic;>n, however, the b\U]._: cow ratios are the highest . in.
these areaso Thus it is apparent that ~unting has little to do with the
bull: cow ratio.. Unt~ the distribution of the various segments of the
moose population is b~ter understood and the extent of the population,_
. or populations as the case may be, are 4etermined in the Koyukuk, the
value of the bull:cO'w ratio will rema:j.n rather vague and nebulous.
RECOMMENDATIONS
Composition counts in the future should be made with the following
problems in mind:
1. All counts should be conducted within as short. a period of
time as possible and approximately at the same time in order to
be comparable.
2. ·Counts should be made in test areas during the rut (September
15-October 10) to determine Whether . or not such count.s. are
feasible and desirable··in the .Int~rior '.:Where population den~· ..
eitie s. are. much l,ess than .. in ::s"ID~th-central Alaska.
3. In the 'Koyukuk,. counts shou.ld be made both on the adjacent flats
and the adjacent uplands to determine whether or not differential
sex distribution occurs., If it does, under what conditions.
4.. A better knowledge of movements is necessary to determine the
effect on distribution during the time counts are conducted.
Prepared by:
SIGURD T o OLOON
Acting Supervisor, Game Restoration
DATE: January 31, 1959
~52-
Approved by:
SIGURD T • -OLSON
Acting Supervisor,
Game ~estoration
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Job Noo 5 Southeast Alaska Moose Studies
PERIOD COVERED~ September 15 -December 31, 1958
ABSTRACT
Thirty-one moose were killed on the Alaska portion of the Stikine
River during the 1958 legal s:easono Age composition of the kill con-
tinued to reflect the heavy cropping of bullso Hunter success con;_
tinued high for the area at 23 percent. Composition counts showed
minimum ratios of 41 calves per 100 cows which are comparable to
heavily hunted areas in the· Matanuska Valleyo An estimate of the
moose population on the Stikine River based on pre-hunting season
sex and age ratios and age distribution of the hunter-kill indicate
a post hunting season population of 310o
OBJECTIVES
To obtain an estimate of total numbers and sex and age composi-
tion of the Stikine Valley moose population, and to record character-
istics of the annual kill by hunters.
TECHNIQUES USED
Aerial composition counts were flown over the Stikine River
valley on September 11 and 12, which was just prior to the opening
of the hunting seasono Accurate identification of animals was pos-
sible through the use of a Hiller B-2 helicoptero The helicopter
was piloted by Joe Soloy 9 with Chuck Graham, John Schwartz and Dave
K~ein as observerso
Additional sex and age composition data was obtained by inter-
viewing hunters at the close of the hunting seasono Collection of
this information from Wrangell hunters was done by Game Management
Agent Bill Sholeso
During the legal open season~ (Septo 15-Oct& 15), jaws were
collected from moose killed by hunters and a record of all moose
taken was kepto Jaws were segregated into age class groupings by
examination of tooth replacement and wearo
FINDINGS
C;omposition· Counts: In conducting the aerial counts, it was
found that the helicopter is an effective tool in securing accurate
identification of sex and age of animals observedo In this respect
and the slow speed, extreme visibility and maneuverability, the
advantage of the use of the helicopter over the small plane is con-
siderable for aerial ·game countingo Results of the aerial counts
are included in Table lo These counts represent only the. sample of
the total herd that was in open areas where observation:was possible.
Comparison of the ratios in Table 1 with composition ratios from the
Matanuska Valley, Susitna and Copper River va,lieys are quite similar.
-53~
Calf-cow ratios and calf perce-ntages a:ppear similar to the mean
values for the south-central Alaska herds., Ratios of bulls per 100
cows, while lower than most of the areas distant from Anchorage, are
never-the-less higher than bull ratios in heavily hunted portions of
the Matanuska Valleyo
Sex and age ratios of moose ·seen by hunters qre included in
Table lo These were obtained by i.:n·terviewing 25 moose hunters from
Wrangell and Petersburg. Sbme variation exists in the bull:cow
ratios obtained by the aerial and ground counts, however, calf:cow
ratios are surprisingly similar in view of the relatively small
sample sizes involved. A possible explanation for the greater ratio
of bulls observed by the hunters is tha:t wh-en bulls were observed,
hunters generally made no further effort to see other moose and con-
centrated on getting the bulls. This·was not the case when cows or
calves were seen first ..
TABLE 1. SEX AND AGE RATIOS -STIKINE RIVER MOOSE, 1958
Cbws & -CdWii! & Total Total Tot a+ Total Moose
Type of Count l Calf 2 Calves C:ows Calves Bulls Observed
Aerial Count
Sept. ll & 12 11 1 32 13 7 5a
Hunter
Observations
Sept .. 15-0ct.l; 93 46 35 174
valves/ Twin Calves/ p-al£ % in Bulls/ Moose/
~ype of Count lQO Cows 100 Cows r_rotal Herd 100 Cows Hr. Flying
; .
!Aerial Count
~ept. 11 & 12 41 8 2·, 22 23
~unter Obser-'
IV~tions. Sept ..
~5-0cto 15 . 49 26 38
'
Th-e Hunter Harvest: Thi·s ·y-ear the total legal harvest of moose
on the· S tikine Riv-er,· within Ala aka, was ·31 -bulls. Twenty-three of
these we·re ·taken by Wrangell hu.nt-e:r:-s, ·se-ven by Petersburg hunters
·and· one by a hunter from another· ar·ea., Out of ·approximately 135
persons hunting the area 70·percent·were from· Wr-angell, 22 percent
from Petersburg and 8 percent from other· areas.. Six moose were taken
in the Muddy River-Thomas Bay area by Petersburg hunters, including·
one cow accidentally sho·t.
This year's kill on the Stikine River is less than in 1957 but
higher than the yearly average since 1952. Table 2 shows a summary
of the annual moose kill on the Stikine River from 1952-1958 in
-54-
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comparison with the length of seasons, numbers of hunters and hunter
successo
The moose kill on the adjacent British Columbia side of the bor-
der was lower than in previous years with only three bulls takeno
These were taken in the Iskut River area by Wrangell hunters employ-
ing Canadian guideso
TABLE 2
Year
1952
1953
1954
1955
1956
1957
1958
TOTAL MOOSE KILL AND HUNTER SUCCESS RATIOS
ON THE STIKINE RIVER, ALASKA
-------n .L 'j .:7c-.L·'7 ./O
Esto Noo Noo of Moose
Length·lf season of <f!unters· Taken
Se:p:to l5=0cto 14 -300 -~r•. 3~
Septo 15-0cto 30 100 12
Septo 15-0cto 5 125 14
Septo 15~0cto 5 150 16
Septc 15-0cto 5 125 30
Septo 15-0cto 15 160 40
Septo 15=0Cto 15 135 31
Averages 156 25
Percent
Success
10
12
11
11
24
25
23
17
The age composition of the kill continues to show a large pro-
portion of young animalso Table 3 shows the yearly age distribu-
tion represented in the harvest as determined from samples of moose
jaws coliectedo It is interesting to note that no bulls over 2~
years of age showed up in this year 9 s jaw sampleo
The fact that •irtually the entire kill is made up of young
animals quite likely contributes to the apparent high quality meat
obtained 9 even though the hunting season occurs during the ruto
The physiological changes which accompany the rut in male ungulates
is not as pronounced in young animals as in the older bullso
TABLE 3 AGE CLASS REPRESENTATION OF HUNTER-KILLED
MOOSE ON THE STIKINE RIVER
1954, 1955, 1957 & 1958
1954 1955 1957 1958
Age Class % Jaws % Jaws % Jaws % Jaws
I (15-17 moo) 8 1 58 7 57 12 59 13
II (2 yrso 3-5 moso) 33 4 8 1 29 6 41 9
III (3 yrso & older) 58 7 33 4 14. 3 0 0
TOTALS 12 12 21 22
-55-
Population .Estimat·e: · It is possible to arrive at a minimum
population estimate for the Stikine River herd by using the age
proportions represented in the kill and the pre-hunting season sex
and ?.ge ratios as a basis· for c·omputa·tiono Age distribution repre-
sented in the annual kill for the past three recorded years shows
approximately 40 percent of the bulls taken to be over l~ years of
age (Table 3).. The average yearly kill for this same period has
been 33 bulls (Table 2)o Therefore, at least 13 bulls (40% of 33),
l~ years of age, or older, had to remain unharvested each year in
order to show up in the following year's killo This value of 13,
plus the average take of 33, equals 46, or the minimum number of
bulls present prior to the hunting season. Using the sex and age
ratios obtained from the pre·-hunting season aerial counts in Table
1, the 46 bulls at a bull:cow rat·io of 22/100 indicates 210 cows of
l~ years or older. The calf:-cow ratio of 41/100 at 210 cows yields
86 calve'S. Adding the bulls, cows and calves, the total pre-hunting
season population was 340 with 310 remaining after the close of the
season. Table 4 outlines the procedure used in arriving at this
estimate.
The population structure; which apparently exists on the Stikine
River, is typical of a heavily hunted moose herd. However, the
adequate calf ratios and the maintenance of a large harvest with no
decrease in hunter-success indicates that bulls are not being over-
harvested. Rausch (Fed. Aid Rep. 4/l/58) reports that l~ year old
bulls participate in the rut in the Matanuska Valley where hunting
pressure has removed a large portion of bulls. Bull:cow ratios of
less than 10 per ~00, with the remaining bulls predominantly l~
years old, indicate that the young bulls in that area must effective-
ly service the cows in order to maintain the calf ratio of 50 per
100 cows. Quite likely, a similar situation exists on the Stikine
whe~e l~ year old bulls are also the only significant age group
remaining after the harvest.
TABLE 4 STIKINE RIVER MOOSE POPULATION ESTIMATE
Assumptions:
1.) Age ratios show 40% of the bulls harvested each year to be
over l~ years of ageo
2.) The average yearly kill is 33 bulls.
3.) Pre-hunting season sex and age ratios:
22 bulls per 100 cows
41 calves per 100 cows
40% X 33 =
13 + 33 -46 -
22 X 100 =
210 roo x 41 =
13 min. no. bulls remaining unharvested
each year.
46 mino pre-hunting season bull population.
210 total no. cows
86 total no. calves.
342 total no. moose prior to
hunting seasono
-56-
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RECOMMENDATIONS
Annual aerial composition counts and the collection of harvest
information should be continued to maintain a current knowledge of
the welfare of this important herdo
Prepared by: Approved
David Ro Klein
Wildlife Mgt. Biologist
Date: January 31, 1959
-57-
by:
~----~~~~-----------Sigurd T. Olson
Acting Supervisor,
Game Restoration