HomeMy WebLinkAboutAPA929ALASKA D E P A R T M E N T 0 F F I S H
J U N E A U, A L A S K A
STATE OF ALASKA
William A. Egan, Governor
DEPARTMENT OF FISH AND GAME
James W. Brooks, Commissioner
DIVISION OF GAME
Frank Jones, Director
Donald McKnight, Research Chief
AND
INTERIOR MOOSE S T U D I E S
by
John W. Coady
Volume I
Project Progress Report
Federal Aid in Wildlife Res toration
Projects W-17-4 and W-17-5, Jobs 1.3R, 1.4R and 1.8R
GAME
Persons are free to use material in these reports for educational
or informational purposes. However, s ince most reports treat only part
of continuing studies, persons intending to use this material in scien-
tific publications should obtain prior permission from the Department of
Fish and Game. In all cases, tentative conclusions should be identifi ed
as such in quotation, and due credit would be appreciated.
(Printed July, 1973)
State:
Cooperator:
Project Nos:
Job No:
Job No.:
JOB PROGRESS REPORT (RESEARCH)
Alaska
John W.
W-17-4 &
W-17-5
1.3R
Coady
Project Title: Big Game Investigations
Job Title: Evaluation of Moose
Range and Habitat
Utilization in Interior
Alaska
Job Title: Evaluation of Moose
Browse and Rumen
Fermentation in Interior
Alaska
Period Covered: July 1, 1971 to June 30, 1973
SUMMARY
This report describes major activities undertaken between February
1971 and June 1973. A vegetation type map of the Tanana Flats was com-
pleted in spring 1972. The vegetation, browse selection by moose and
hares, and soil conditions in different habitats in the Tanana Flats and
in the Elliott Creek burn on the Little Chena Drainage were described
during summer 1972. Gross trends in moose -food habits were examined by
identifying .the botanical composition of over 100 rumen content samples
collected during four seasons near Fairbanks. Estimates of seasonal
energy requirements and rates of rumen fermentation and food consumption
by moose were obtained between May 1972 and April 1973 by measuring
volatile fatty acid (VFA) production, total weight and water content,
and chemical composition of rumen contents, and by extensively reviewlng
the literature. Nutritional status of moose and quality of moose range
may be reflected by rates of rumen fermentation.
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Summary ••
Objectives •••
Background.
Procedures.
Vegetation Type Map. • • . .
CONTENTS
Botanical Composition and Soil Conditions. •
Botanical Composition of Rumen Contents .•
Chemical Composition of Moose Rumen Contents, Energy
Requirements and Rumen Fermentation in Moose •
Findings and Conclusions •.••••..•..•
Vegetation Type Map ••••••.•.•••
Botanical Composition and Soil Composition •
Moose Use. • • • • • . • • • •
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Botanical Analysis of Moose Rumen Contents • 14
Chemical Composition of Moose Rumen Contents and Energy
Requirements and Rumen Fe~mentation in Moose •
Acknowledgments • •
Literature Cited.
OBJECTIVES
. 23
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The objectives of this study are: 1) to construct a vegetation
type map of the Tanana Flats; 2) to characterize botanical composition
and soil conditions of major vegetation types in the Tanana Flats, and
evaluate browse preference by both moose (AZces aZces) and hares (Lepus
americanus) in each habitat type; 3) to analyze the botanical composi-
tion of moose rumen contents collected near Fairbanks during different
seasons; 4) to analyze the chemical composition of moose rumen contents
collected during different seasons for components which reflect the
relative digestability of the forage; and 5) to estimate the seasonal
energy requirements and measure factors associated with rumen fermenta-
tion rates in moose which reflect nutritional status of the animal and
quality of the food resource.
BACKGROUND
See Job 1.8R of this report.
PROCEDURES
Vegetation Type Map
A vegetation type map of the Tanana Flats was preoared from black
and white aerial photographs (scale 1" :1320 1 ) taken during the sunnners
of 1968, 1969 and 1970. Identification of taxonomic units was ba8ed on
stereoscopic examination of photographs and on field observation. Map
units delineated on photographs were transferred using a light table to
USGS topographic maps printed on photographic drafting film. Blue-line
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copies of the finished type map were printed from the film.
Several qualifications regarding the type map should be noted.
Shapes of map units may differ from their appearance in the field since
distinct boundaries between vegetation types seldom exis.t in nature.
Aerial photographs were taken during relatively wet (June) and dry
(August) months over three years, and therefore water levels in ponds
and sloughs may differ from their present condition. In particular,
1968 photographs may indicate above normal water levels due to previous
flooding in 1967. Aberrations in photographs may slightly distort true
shapes of particular map units, although positions relative to surround-
ing units are correct.
In a project of this magnitude, using black and white photographs,
errors in photo interpretation are unavoidable. Some taxonomic· units
have undoubtedly been incorrectly identified, especially when the inter-
preter was required to classify certain mixed vegetation stqnds based on .
dominant species. However, these errors are believed to represent only
a small fraction of all map units and should not significantly affect
the usefulness of the map.
Five major taxonomic units were identified:
Herbaceous Bog: designated by number "1" (blue), and consisting of
marshes, shallow ponds and their aquatic margins, and shallow streams
where movement of water is slow enough to support emergent vegetation.
Heath Bog: designated by number "2". (white), and consisting primarily
of low shrubs and widely scattered trees. Scattered patChes of shrub
birch (Bet.ula glandulosa), paper birch (Betula papyrifera), willow,
spruce, and tamarack (Larix laricina) also occur.
Tall Shrub: designated by number "3" (yellow), and consisting primarily
of willow and alder.
Deciduous Tree: designated by number "4" (red), and consisting primarily
of paper birch, quaking aspen (Populus tremuloides), and cottonwood ~
(Populus balsamifera).
Conifer Tree: designated by number "5" (gre~n), and consisting primarily
of black spruce (Picea mariana), white spruce (P. glauca) and tamarack.
Two burns were outlined on the map. One burn of approximately 200
km2 on the east side of the Flats and south of Salchaket Slough occurred
in 195 7. The secortd burn of approximately 25 km2 near the Blair Lakes
occurred during summer 1969. A solid line indicates known boundaries,
while a dotted line indicates approximate boundaries of the burns.
Unclass.ified area is designated by "uc" and consists primarily of
deep lakes and steep rocky slopes.
2
Botanical Composition and Soil Conditions
Site characteristics and plant associations in six heath bog, six
tall shrub, two deciduous tree and three conifer tree habitats on the
Tanana Flats, and in two tall shrub and one heath bog habitats in the
Elliott Creek burn in the upper Little.Chena River drainage were described
using a sampling scheme developed by Ohmann and Ream (1971). The scheme
includes determining the approximate age of the stand by counting annual
growth rings of the largest trees, recording species, size, and density
of trees and shrubs, and determining the species and percent coverage of
low growing plants. Depth to permafrost, moisture content, and mineral
composition of the soil in each stand was also recorded.
Utilization of browse species by·moose and hares in three heath bog,
five tall shrub, and one deciduous tree stand in the Tanana Flats was
evaluated using range survey techniques similar to those described by
Cole (1963). Sixty to 200 individual plants of each major browse
species in a stand were sampled using closest plant sampling techniques,
and data were recorded on Alaska Department of Fish and Game Browse
Survey forms-(Fig. 1). A numerical index of one to three was used to
indicate age class , where one indicates seedlings less than four and
one-half feet (137 em) high, two indicates saplings greater than four
and one-half feet (137 em) high but less than two inches (5 em) in
diameter at breast height (dbh), and three indicates trees greater than
two inches (5 em) dbh. Canopy range is the height range above ground
from the first lateral branch to the top of the plant. Browse range for
moose and for hares is the height range above ground of browsing by each
species during the previous year. A numerical index of 0 to 4 was used
to indicate browse class for moose and for hares, where 0 indicates no
browsing during the previous year, .and-1, 2, and 3 indicate 1-33 percent,
34-66 percent, and 6 7-100 percent, respectively, of the lateral branches
within the browse range for moose and hares browsed during the previous
year. A numerical index of 0 to 3 was used to indicate barking by hares,
where 0 indicates no barking, and 1, 2, and J indicate a subjective
evaluation of light, moderate, and severe (or girdled) barking, respectively.
Botanical Composition of Rumen Contents
In this preliminary study, no attempt was made to standardize the
quantity of material collected from individuaL moose stomachs. A one-
quart subsample was randomly collected from each sample and analyzed.
This was done without knowing whether the one-quart subsample was
representative of the gallons of material normally in a moose stomach.
The one-quart subsamples were emptied into a gang of sieves and
washed with fresh water. Material retained by a 6. 35 mm mesh sieve was
separated by plant parts (twigs, fruit, leaves, etc.) to species where
possible. This mesh sieve was used without determining its effectiveness
in retaining food items. Food items that could not be readily identified
to species were grouped into general categories of foods (e.g. , leaves ,
twigs, fruits). All data were coded and recorded for direct automatic
data processing, using summary programs developed by Cushwa et al. (19 73).
Frequency of occurrence, the number of samples each food item occurred
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Figure 1. Alaska Department of Fish and Game browse survey form. (See ·
text for description of figure.)
Stand Area Date
Veg Type Observer
Remarks
Moose Hares
Age Canopy Browse Browse Browse Browse
Sp Cl Range Range .Class Range Class Barking
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in, was calculated and reported. Neither volume nor importance value
were reported because of the large number of factors which influence
volume calculations over which an investigator has no control.
Chemical Composition of Moose Rumen Contents, Energy Requirements and
Rumen Fermentation in Moose
Procedures have been described in two previous publications (Coady
and Gasaway, 1972; Gasaway and Coady, 1973), and will not be reported
here.
FINDINGS AND CONCLUSIONS
Vegetation Type Map
Approximately seven man-months of labor, $1,000 in materials, and
20 hours of air charter were devoted to this project. The type map was
completed in April 1972 and is located in the Fairbanks roame Division
office.
Botanical Composition and Soil Composition
The regional vegetation of northern boreal forests in Alaska,
referred to by the Russian term "taiga," consists primarily of low,
open-growing spruce forests, occasional stands of well developed spruce
and hardwoods, and frequent tracts of treeless or sparsely timbered
bogs. On south facing slopes and well drained sites the forest consists
___ of _white_ s12r1.1ce and hardwood stands of quaking_ aspe_n .;m,ci_pg.p~r l:>ir_ch_, __
while on cool, north facing slopes and poorly drained lowlands climax
vegetation is generally black spruce, tamarack and bogs.
Extensive lowlands, locally referred to as "flats" or "muskeg,"
cover broad alluvial plains throughout interior Alaska, from the south
slope of the Brooks Range to the southern coastal forests, and from the
Alaska-Canada border nearly to the Bering and Chukchi seas (Wahrhaftig,
1965; Johnson and Hartman, 1969). Approximately 30 percent of this area
is forested, while the remaining land consists of bogs, shrub thickets,
and alpine tundra (Viereck, in press). Surface vegetation patterns are
closely related to topography, drainage, presence or absence of perma~
frost and past forest fire history.
Surface features in lowland areas frequently include extensive
flood plains with little relief, meander scars and oxbow lakes, terraces,
and alluvial outwash deposits (Black, 1958; Wahrhaftig, 1965). Loess,
sand, and outwash of Quaternary age, organic deposits formed in bogs,
and recently deposited alluvium frequently overlay a micaceous schist
bedrock (Dutro and Payne, 1957; Viereck, in press). Forest soils are
generally shallow with poorly developed profiles. Piedmont st'reams,
many of glacial origin, change from braided to tightly meandering
tributaries as they enter lower elevations.
Permafrost, or permantly frozen ground, is a widespread phenomenon
5
throughout much of the Alaskan taiga. Between the Alaska Range and the
Brooks Range permafrost occurs in all areas except for south facing
slopes and recently deposited alluvium, while $OUth of the Alaska Range
permafrost is sporadic in occurrence, and is found only in bogs and on
north facing slopes (Vier~ck, in press). An important influence of
permafrost on vegetation patterns results from the frozen impervious
substrate which prevents lateral movement and downward percolation of
soil water (Benninghoff, 1952). Thus, permafrost results in saturated
soils or standing water throughout much of the taiga.
Regional distributions of vegetation types and permafrost in low-
land areas are inextricably interrelated. Insulation provided by black
spruce and bog vegetation prevents melting of permafrost during summer
months' while permafrost governs climax vegetation during the course of
succession (Benninghoff, 1952; Drury, 1956). Disjunct stands of shrubs
and deciduous trees scattered throughout Alaskan lowlands ·are frequently
the result of burning of climax vegetation, which results in lowering of
permafrost tables, and formation of a substrate temporarily favorable to
subclimax vegetation (Viereck, pers. comm.).
Geologically and vegetatively the flats of interior Alaska consist
of treeless or nearly treeless bogs and more or less forested areas
surrounding or occurring tvithin the bogs. Drury (1956) and Viereck
(1970a, 1970b) have discussed lowland forest succession and origin of
bogs along braided or meandering streams in interior Alaska. Freshly
deposited alluvium is first colonized by willow (Salix spp.) or alder
(Alnus spp.), and later by balsam poplar (Populus balsamifera). An
understory of low shrubs and horsetails (Equisetwn spp.) along with
white spruce seedlings may develop beneath the poplars. As white spruce
matures an organic ground layer of mosses, herbs, and low shrubs develops,
resulting in permafrost formation and a substrate more favorable to
black than to white spruce after 200 to 300 years.
Local disturbance of the insulating organic layer in black spruce
forests may result in shallow thawing of the permafrost, water accumula-
tion, and bog formation (Benninghoff, 1952; Drury, 1956). · Development
and expansion of bogs are frequently indicated by angular growth of
trees due to soil instability. The resulting vegetation over extensive
lowland areas becomes an intricate mosaic of black spruce forests, bogs,.
shrub and hardwood sub-climax communities, a8 well as numerous intermediate
stages.
Floristics of northern lowlands have been studied by several workers
including Ritchie (1959) and Larsen (1965) in subarctic Canada, Hanson
(1951, 1953) in western Alaska, Drury (1956) in the upper Kuskokwim River
region of Alaska, and Johnson and Vogel (1966) in the Yukon Flats of
Alaska. In addition, Anderson (1959), Hulten (1968), and Viereck and
Little (1972) have described the circumpolar distribution of trees,
shrubs, and herbs found in Alaska.
Recent alluvial deposits on lowland floodplains throughout interior
Alaska are generally colonized first by horsetails (Equisetwn arvense),
grasses (Calamagrostis canadensis), willows (Salix alaxensis~ S.
6
arbusculoides, S. bebbiana), and alders (lllnus tenuifolia). As balsam
poplar and later, white spruce or mixed white spruce-paper birch become
established, herbs such as wintergreen (J>yrola spp.) and fi reweed
(Epilob1:wn angustifolium), and low shrubs such as roses (Ro::a acic:ulor•i::),
currants (Ribes triste), and high bush cranberry (Wbur'Ylurn edulc) appear ..
Accompanying the replacement of white spruce and paper birch by black
spruce is a gradual increase in the sphagnum moss coVer (Sphagnum
capiUaceum~ S. girgensobnii, S. fuscus, and S. rubeUum) and growth of
a dense shrub layer of bog blueberry ( Vacciniwn uliginosum), Labrador
tea (Ledwn groenlandicum, L. decumbens) and birch (B. glandulosa, B.
nana). A dense ground cover of sphagnum and low shrubs, along ~vith
willows (S. pulchra~ S. bebbiana), and widely spaced paper birch, black
spruce, or tamarack may replace stands of black spruce. The recurring
process of bog formation and subsequent reforestation has been described
in detail by Drury (1956).
All stages of· bog development, from open water to black spruce
forest are found in Alaskan lowlands. Sphagnum mosses, sedges (Carex
spp. and Eriophorum spp.) and pond lilies (Nuphar polysepalum and
Nymphaea tetragona) are common in open water, while other sedges (C.
aquati lis) and horsetails (E. fluviatile, E. palustre) are found along
margins of ponds and shallow flowing water. Bog shrubs, such as bog
rosemary (Andromeda polifolia), Labrador tea, bog blueberry (Vaccinium
uliginosum), swamp cranberry (Oxycoccus microcarpus), leather-leaf
(Chamaedaphne calyculata), cloudberry (Rubus chamaemorus) , dwarf birch
(Betula nana) and shrub birch along with sphagnum mosses are common on
moist ground.
The vegetation of the Tanana Flats, a 130 0 square-mile alluvial
lowland lying immediately south of Fairbanks, Alaska, has been recently
studied (Coady and Simpson, in ~·). The area is bounded on the south
by the rugged Alaska Range, on the north and east by the glacial Tanana
River, anci on the west by the glacial Wood River, and is part of the
much larger Tanana-Kuskokwim physiographic province described by
Wahrhaftig (1965).
Surface deposits from glacial streams flowing into the Tanana Flats
on the south form a belt of broad coalescing fans that grade from coarse
sand and gravel near the mountains to fine sand and silt at lower
elevations. Haterial manteling the eastern and northern portion of the
Flats has been deposited by the Tanana River (Andreasen, et al., 1964).
Except for1 scattered low hills of granite, ultramafic rocks, and possibly
Precambrian schist, the Flats are an area of little relief (Andreasen,
et al., 1964). The entire region is underlain by permafrost (Black,
1958; Wahrhaftig, 1965), and drainage is poor, resulting in numerous
small, shallow ponds, extensive bogs, and meander scars.
Herbaceous bogs occur primarily in the northern portion of the
Flats and cover approximately 7 percent of the area. Vegetation is
dominated by emergent species, and live trees and shrubs are totally
absent (Table 1). Stagnant or slowly flowing water depths vary season-
ally, although they tange from several inches to several feet after
spring run-off. Bog bottoms consist of a meter or more of dead and
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Table 1. Floristics of herbaceous bog community; Tanana Flats, Interior Alaska.
Trees Tall Shrubs Low Shrubs
None None None
Herbaceous
Rotentilla palustris
Gramina spp.
Eriophorum. spp .
Equisetum hiemale var. califor~icum
Equisetum fluviatile
Equisetum palustre
Iris. setosa subsp. interior
Ranllnculus Gmelini subsp. Purshii
· Ranunculus sp •
Sanguisorba officinalis
Petasites frigidus
Petjsites sagittatus
Valeriana capitata
Caltha palustris subsp. arctica
Gardamine sp.
Rum:ex sp.
Carex spp.
Potentilla spp.
Utricularia vulgaris subsp. macrorhiza
Typha latifolia
Nymphae tetragona
ChEysoplenium tetrandrum
Hippuris vulgaris
utricularia minor
decaying vegetation, and permafrost depths are presumably well below the
upper surface of organic material.
Heath bogs are widespread throughout the Flats, occupying approxi-
mately 40 percent of the land. ·Dominant vegetation consists of mosses
and shrubs, although scat"tered trees and various herbs. rooting on
precipituous sedge hummocks are common (Table 2). Both mineral soil
and permafrost tables occur within a meter of the surface, although
seasonal thaw may extend to greater depths in some areas. Soil moisture
is high and shallow standing water is common in many areas.
Tall shrub communities occur throughout approximately 10 percent of
the Flats but are most frequent along rivers, streams, and sloughs and
along margins of ponds and meander scars. Recent wildfire burns may
also support tall shrub communities. Vegetation ranges from pure to
mixed stands of willow and alder with a dense understory of mosses, herbs,
and low shrubs in poorly drained sites (Table 3). Exposed miner.al soil,
low moisture content, and absence of permafrost are common on recent
alluvial deposits, while a thick organic layer, impeded drainage, and
high permafrost tables ~re found in other areas.
Discontinuous pure or mixed stands of paper birch, quaking aspen,
or balsam poplar occur throughou~ approximately 8 percent of the Flats,
particularly on slightly elevated land and on coarse river alluvium.
Understory vegetation ranges from a dense herbaceous cover in cqttonwood
stands to mixed herbs and low shrubs in aspen and birch stands. Scattered
willows and alders are common among cottonwood communi ties (Table 4) .
Well drained mineral soil lies close to the surface and permafrost tables
are deep or nonexistent.
Scattered conifer stands in the western portion and extensive low,
dense black spruce and occasional tamarack forests in the southern area
cover approximately 35 percent of the Flats. Mature white spruce
forests with a ground vegetation of low shrubs and mosses are common
near streams, while black spruce forests underlain by a dense mat of
moss, herbs, and low shrubs grow in poorly drained areas (Table 5).
Soil organic layer, moisture content, and permafrost tables range from
low in young white spruce stands to high in black spruce and tamarack
stands.
Moose Use
The seasonal importance to moose of local flatlands south of the
Brooks Range is diverse. Lowland areas, by virtue of their abundant
herbaceous vegetation, are generally important summer ranges for moose
of all sex and age groups. Furthermore, seclusion provided by numerous
dense stands of tall shrubs and trees frequently creates favorable
calving areas for large numbers of moose (Bishop, 1969).
On the Tanana Flats moose commonly feed in herbaceous bogs from
spring thaw to late summer. However, greatest use of this habitat
appears to be during early to midsummer. During late summer moose may
feed more frequently on herbaceous arid woody browse in heath bog and
tall shrub communities.
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Table 2. Floristics of heath bog community; Tanana Flats, Interior Alaska.
Trees
Betula papyrifera subsp.
humilis
Picea glauca
Picea mariana
Larix laricina var.
alas kens is
Tall Shrubs
Salix bebbiana
Salix glauca
Salix arbusculoides
Salix planifolia subsp.
pulchra
Betula papyrifera x
glandulosa
Low Shrubs
Salix brachyocarpa subsp.
niphoclada
Salix myrtillifolia
Betula nana
:Ledum paltiStre subsp.
·decumbens
. Ledum palustre subsp.
groenlandictnn
yaccirtium uliginosum
subsp. alpinum
Vaccinium vitis-idaea
subsp. minus
Andromeda polifolia
:Myrica gale var. tomentosa
Potentilla fruticosa
Chamaedaphne calyculata
Linnaea borealis
Arctostaphylos uva-ursi
Arctostaphylos rubra
· Rosa. acicularis
Oxycoccus microcarpus
Herbaceous
Rubus chamaemorus
Potentilla palustris
Eriophorum spp.
Gramina spp.
Rubus arcticus
Stellaria spp.
.. Epilobium angustifolium subsp .
angus tif o li um
Cornus canadensis
Pyrola spp.
Equisetum pratense
Equisetum variegatum
·Equise tum arvense
Equisetum scirpoides ·
Equisetum fluviatile
Pedicularis labradorica
Saus.surea sp .
Mertertsia paniculata var. paniculata
Mertensia sp.
Solidago sp.
Lupinus arcticus
Iris setosa subsp. interior
s;nsuisorba officinalis
Petasites frigidus
Trientalis europea subsp. arctica
Ranunculus sp.
Spiranthes Romanzoffiana
Table 3. Floristics of tall shrub community; Tanana Flats, Interior Alaska.
Trees Tall Shrubs
Populus balsamifera subsp. Salix arbusculoides
balsamifera Salix bebbiana
Picea glauca Salix monticola
Picea mariana Salix glauca
Betula papyrifera subsp. Salix lanata subsp.
humilis richardsonii
Salix lasiandra
Salix hastata
Salix planifolia subsp.
pulchra
Salix novae-angliae
Alnus crispa subsp. crispa
Alnus incana subsp.
tenuifolia
Betula papyrifera x
glandulosa
Low Shrubs
Rosa acicularis
Potentilla fruiticosa
Ledum palustre subsp.
groenlandicum
Vaccinium uliginosum
subsp. alpinum
Vaccinium vitis-idaea
subsp. minus
Arctostaphylos rubra
Arctostaphylos uva-ursi
Ribes hudsonianum
Ribes tris te
Rubus idaeus subsp.
melanolasius
Viburnum edule
Linnaea borealis
Myrica gale var. tomentosa
Oxycoccus microcarpus
Herbaceous
Gramina spp.
Carex spp.
Equisetum arvense
Equisetum palustre
Equisetum pratens.e
Equisetum fluviatile
Equisetum scirpoides
Potentilla spp.
Achillea siberica
Rubus arcticus
Stellaria spp.
Pyrola secunda
Pyrola spp.
Epilobium angustifolium subsp.
arigustifolium
Cornus canadensis
Erigeron sp.
Trientalis europaea subsp. arctica
Petasites saggitatus
Petasites frigidus
Moneses uniflora
Aster sp.
Galium boreale
Galium trifidum subsp. trifidum
Fragaria virginiana subsp. glauca
Mertensia paniculata var. paniculata
Rubus chamaemorus
Parnassia palustris subsp. neogaea
Table 4. Floristics of deciduous tree community; Tanana Flats, Interior Alaska.
Trees
Populus balsamifera subsp.
balsamifera
Populus tremuloides
Betula papyrifera subsp.
humilis
Picea glauca
Picea.mariana
Tall Shrubs
Alnus crispa subsp. crispa
Alnus incana subsp.
tenuifolia
Salix alexensis
Salix interior
Salix lanata subsp.
richardsonii
Salix novae-angliae
Salix planifolia subsp.
pulchra
Low Shrubs
Rosa acicularis
Ribes triste
Ribes sp.
Rub.us idaeus subsp.
melanolasius
Herbaceous
Stellaria ~·
. Pyrola . secunda
Epilobium angustifolium
Gramina spp .
Equisetum silvaticum
Equisetum palustre
Equisetum arvense
Equisetum pratense
Poiygonum alpinum
Mertensia paniculata var.
Trientalis europea subsp.
Thalictrum sparsiflorum
Galium boreale
Artemsia sp.
paniculata
arctica
Table 5. Floristics of conifer tree community; Tanana Flats, Interior Alaska.
Trees Tall Shrubs
Picea glauca Alnus crispa subsp. crispa
Picea mariana Alnus incana subsp.
Larix laricina var. tenuifolia
alaskensis Salix alexensis
Betula papyrifera subsp. Salix bebbiana
humilis Salix glauca
Populus balsamifera subsp. Salix arbusculoides
balsamifera
Low Shrubs
Viburnum edule
Rosa acicularis
Ribes hudsonianum
Ribes sp.
Rubus idaeus subsp.
melanolasius
Empetrum hermaphroditum
subsp. nigrum
Arctostaphylos uva-ursi
Vaccinium vitis-idaea
subsp. minus
Linnaea borealis
Herbaceous
Equisetum arvense
Equisetum pratense
Equisetum fluviatile
Equisetum palustris
Equisetum scirpoides
Cornus canadensis
Cornus stolonifera
Gra.niina spp .
Trientalis europea subsp. arctica
Stellaria spp.
Mertensia paniculata
Rubus arcticus
Pyrola spp.
Geocaulon lividum
Potentilla ~·
Epilobium angustifolium subsp.
angustifolium
Goodyera repens
Galium sp.
Thalictrum sparsiflorum
Galium trifidum subsp. trifidum
Cypripedium guttatum subsp.
gutta tum
Platanthera obtusata
Listera borealis
Use of different lowland areas by moose during fall and winter
depends largely upon the availability of adequate quality winter browse.
Following the 600 square-¢le 194 7 burn on the Kenai Peninsula lowlands,
white birch regrowth created major winter rarige ·for large numbers of
moose.· Spencer and Chatelain (1953) discussed other lowland areas in
Alaska which have become important winter moose range following fires.
Generally, the Tanana Flats do not seem to be good winter moose
range, and large scale emigration of animals during fall and early
winter supports this conclusion. While several species of willows are
widely scattered throughout portions of the Flats, they are often old
and extremely decadent. Apparently, changes in local edaphic factors,
such as soil temperature, moisture, and organic content, due to the
dynamic nature of bog formation, frequently create substrates unfavorable
to continued growth of tall shrub and other sub-climax communities.
However, vigorous growth of shrubs occurs on·well drained recent deposits
along some streams, and these areas may supnort large numbers of moose
during winter.
The effects of fire in creating winter moose brows·e on the Tanana
Flats'have been variable. Although much of the Flats has burned within
the past 50-100 years, early seral stages have frequently not developed
or have been of short duration and consequently of minor importance to
moose. However, a 75 square-mile burn in 1957 on the east side of the
Flats has resulted in exposure of mineral soil and considerable reduction
in permafrost levels in many areas; Consequently, much of the area is
well drained and supports moderately dense, mixed stands of willow
(Salix glauca, S. arbusculoides, S. bebbiana), poplar (Populus trerrruloides,
P. balsamifera), and paper birch. For the past several vears the area
has supnorted a sizable number of moose during winter. Other recent
burns of considerably smaller size have provided limited winter browse
to a few animals.
A more complete description of the vegetation of the Tanana l"lats
will be presented in a future publication (Coady and Simpson, in prep.).
Data from the moose and hare browse study have not been fully
summarized, and therefore, no quantitative results are available.
However, observations leave little doubt that deciduous shrubs and
· trees preferred by moose are also used extensively by· hares. These
species include willows (Salix spp.), paper birch, quaking aspen and
cottonwood. The portion of the plant hrowsed by the two animals differs,
of course, depending largely on snow depths. The only conifer trees
occurring in interior Alaska, tamarack, black S.Pruce and white spruce,
are used extensively by hares and rarely by moose.
Botanical Analysis of Moose Rumen Contents
During the winter of 1970-71 (September through }fuv) the Fairbanks
weather station recorded the heaviest total snowfall (307 em) since it
began keeping records during the winter of 1933-34. Maximum snow depths
on the ground exceeded 101 em in January. Examination of 44 samples of
moose stomach contents collected during this period revealed a. diet
14
primarily of deciduous woody plants (Table 6). Of the identified food
items, twigs of willow, birch, aspen, and alder, respectively, were
most frequently eaten. Other foods, ranked by frequency, included fruit
(catkins, seeds, or flower parts) , dry aspen leaves, spruce twigs, willow
fruit, and dry leaves. A small quantity of unidentified herbaceous
material was found in one sample.
During the winter of 1971-72, total snowfall was 229 em in January.
Examination of 10 samples collected during this time indicated that the
diet again consisted primarily of deciduous woody materials (Table 7).
Of the identified food items, willow twigs, birch twigs, birch fruit,
alder, aspen, and cottonwood twigs, alder fruit, followed by dry birch
leaves, green spruce needles, willow fruit and dry leaves, were the most
frequently eaten foods. One sample contained a small quantity of
unidentified sedges. The record snowfall during the winter of 1970-71,
when 140 em more snow than fell during 1971~72, did not influence the
frequency of occurrence of major food items found in stomach contents
of moose. It is also interesting to note that during periods of greater
than normal snowfall, when moose died from malnutrition, only one of the
44 samples contained spruce. It therefore appears that spruce does not
constitute a major portion of the moose's winter diet near Fairbanks,
Alaska. It also appears that spruce is not used as an emergency food
by moose.
During the spring of 1971, 15 samples of moose stomach contents
were collected near Fairbanks. Analysis of these samples revealed that
hardened twigs of willow and birch were most frequently eaten (Table 8).
Other foods, in descending order, were fruit and dry willmv leaves,
hardened aspen twigs, green willow leaves, hardened alder twigs, sedges,
hardened Vaccinium twigs, and succulent willow twigs. ·
Six samples collected during spring 19 72 were analyzed. Hardened
willow and birch twigs were found in all samples, and birch fruit and
hardened alder twigs occurred in half the samples (Table 9).
Seven samples were collected during the fall of 1971. Hardened
twigs of willow and birch were followed in descending order by birch
fruit, dry and green willow leaves, hardened aspen twigs, green birch
leaves, hardened alder twigs, and Equisetum (Table 10).
During the fall of 1972, 15 samples from the Fairbanks area con-
tained hardened willow and birch twigs, dry leaves of willow and birch,
hardened twigs of cottonwood and alder, and Equisetwn (Table 11).
Ten samples were coll.ected during the summer of 19 72. All samples
contained green willow leaves, while succulent willow twigs and Equisetum
were found in nine samples. Six samples contained green shrub birch
leaves, five grass, and four hardened birch twigs (Table 12).
A more complete analysis and discussion of the data has been
recently completed (Cushwa and Coady, 1973), and will not be nresented
·here.
15
Table 6. Moose stom'ach contents analysis from Game Management Unit
20A and 20B during winter 1970-71. Sample size = 44.
Food Item
Woody
Identified
Trees
Aspen
Birch
Spruce sp.
Tall Shrubs
Willow sp.
Alder
Unidentified
Herbaceous
Unidentified
Plant Part
Pry leaves
Hardened twigs
Hardened twigs
Hardened twigs
Fruit
Dry leaves
Hardened twigs
Fruit
Hardened twigs
Hardened stems
Dry leaves
Green leaves
Dead stems I bark
Dry sterns anq leaves
1 Relative frequency of occurrence.
16
Frequertcy1.
2.3
56.8
70.5
2.3
2.3
2.3
86.4
4.6
25.0
93.2
31.8
2.3
34.1
2.3
Table 7. Moose stomach contents analysis from Game Management Unit
20A and 20B during winter 1970-71. Sample size = 10.
Food Item
Woody
Identified
Trees
Aspen
Birch
Cottonwood
Spruce sp.
Tall Shrubs
Willow sp.
Unidentified
Herbaceous
Unidentified
Plant Part
Hardened twigs
Fruit
Dry leaves
Hardened twigs
Hardened twigs
Green needles
Fruit
Dry leaves
Hardened twigs
Hardened twigs
Dry deciduous leaves
Green deciduous leaves
Dead twigs I bark
Sedge
1 Relative frequency of 9ccurrence.
17
Frequencyl
20.0
70.0
10.0
90.0
20.0
10.0
10.0
10.0
10.0
100.0
40.0
5.0
10.0
10.0
Table 8· Moose stomach contents anaJ,ysis from Game Hanagement Unit
20A during spring 1971. Sample size = 15 ..
Food Item
Woody
Identified
Trees
Aspen
Birch
Spruce sp.
Tall Shrubs
Willow sp.
Alder
Shrub birch
Low Shrubs
Vaccinium sp.
Unidentified
Herbaceous
Unidentified
Plant Part
Succulent twigs
Hardened twigs
Hardened twigs
Hardened twigs
Fruit
Green leaves
Dry leaves
Succulent twigs
Hardened twigs
Fruit
Hardened twigs
Hardened twigs
Green leaves
Hardened twigs
Hardened stems
Dry deciduous leaves
Dead stems I bark .
Grass
Mushrooms
Sedges
1 Relative frequency of occurrence.
18
Frequency1
6". 7
20.0
80.0
6.7
26.7
20.0_
26.7
13.3
86.7
. 6. 7
13.3
6.7
6.7
13.3
100.0
13.3
33.3
6.7
6.7
13.3
Table 9. Moose stomach contents analysis from Game Management Unit
20A during spring 1972. Sample size = 6.
Food Item
Woody
Identified
Trees
Aspen
Birch
Cottonwood
Tall Shrubs
Willow sp.
Alder
Unidentified
Plant Part
Hardened twigs
Fruit
Hardened twigs
Hardened twigs
Hardened twigs
Fruit
Dry leaves
Hardened twigs
Hardened twigs
Green deciduous
1 Relative frequency of occurrence.
19
Frequency1
16.7
50.0
100.0
16.7
100.0
16.7
16.7
50.0
100.0
leaves 16.7
Table 10. Moose stomach contents analysis from Game Management Unit
20A and 20B during fall 1971. Sample size= 7.
Food Item
Woody
Identified
Trees
Aspen
Birch
Tall Shrubs
Willow sp.
Alder
Shrub birch
Low Shrubs
Vaccinium sp.
Unidentified
Herbaceous
Idetiti fied
Equiseturn
Unidentified
Plant Part
Hardened twigs
Fruit
Green leaves
Dry leaves
Hardened twigs
Green leaves
Dry leaves
Hardened twigs
Hardened twigs
Dry leaves
Hardened twigs
Green leaves
Hardened stems
Dry leaves
Green leaves
Dry stems and leaves
Sedges
Fruit
Grass
1 Relative frequency of-occurrence.
20
Frequency1
28.6
42.9
28.6
14.3
71.4
4.2. 9
42.9
85.7
28.6
14.3
14.3
14.3
100.0
14.3
28.6
28.6
14.3
14.3
14.3
14.3
Table il. Moose stomach contents analysis from Game Management Unit
20A and 20B during fall 1972. Sample size = 15.
Food Item
Woody
Identified
Trees
Aspen
Birch
Cottonwood
Spruce sp.
Larch
Tall Shrubs
Willow sp.
Shrub birch
Alder
Low Shrubs
Vaccinium
vitis-idaea
Ledum
Arctostaphylos
Unidentified
Herbaceous
Identified
Equisetum
Unidentified
Plant Part
Dry leaves
Hardened twigs
Green leaves
Dry leaves
Hardened twigs
Green leaves
Hardened twigs
Dry needles
Hardened twigs
Green leaves
Dry leaves
Hardened twigs
Dry leaves
Fruit
Green leaves
Dry leaves
Hardened twigs
Green leaves
Green leaves
Dry leaves
Hardened twigs
Dry deciduous leaves
Green deciduous leaves
Grass
Hush rooms
1 Relative frequency of occurrence.
21
Frequencyl
13.3
6.7
6.7
20 .o
66.7
6.7
20.0
6.7
6.7
6.7
40.0
86.7
13.3
6.7
6.7
6.7
20.0
6.7
6.7
6.7
86.7
20.0
53.3
20.0
6.7
13.3
Table 12. Moose stomach contents analysis from Game Management Unit
20A during summer 1972. Sample size = 10.
Food Item
Woody
Identified
Trees
Aspen
Birch
Tall Shrubs
Willow sp.
Shrub birch
Alder
. Salix pulchra
Unidentified
Herbaceous
Identified
Equisetum
Unidentified
Plant Part
Green leaves
Succulent twigs
Hardened twigs
Green leaves
Succulent twigs
Green leaves
Dry leaves
Succulent twigs
Green leaves
Dry leaves
Succulent twigs
-Green leaves
Succulent· twigs
Green deciduous leaves
Dead twigs I bark
Grass
1 Relative frequency of occurrence.
22
Frequency1
10.0
10.0
40.0
100.0
90.0
60.0
10.0
10.0
10.0
10.0
10.0
20.0
20.0
10.0
90.0
50.0
Chemical Composition of Moose Rumen Contents and Energy Requirements and.
Rumen Fermentation in Moose
Findings have been reported in two previous publications (Coady and
(;asaway, 1972; Gasaway and Coady, 1973), and will not be nresent.ed again
at this time. However, an abstract of the most recent publication
(Gasaway and Coady, 1973) is given below:
A review of seasonal energy requirements and utilization of food by
moose, with reference to other wild and domestic species, is presented.
Energy requirements are difficult to estimate because no metabolic
studies have been conducted with moose and comparative data from other
wild and domestic species differ widely. It is assurn:ed that basal
metabolic rate (BMR) conforms to the empirical relationship of wei~h t to
metabolic rate, where BMR = 70 • 75 , and maintenance demands approximate
1. 7 times BMR. Energy requirements of female moose begin to increase
significantly in Marcl). due to pregnancy and reach a peak of three to
four times BMR in June, due to lactation and linogenesis.
Major seasonal differences in rumen contents and estimates of food
consumption by moose are described. Rumen fill in cow moose was greatest
during early winter, lowest during late spring, and intermediate during
summer. Percent dry matter was lowest during sunrrner and highest during
winter. Washed rumen contents were higher in crude protein and lower in
acid detergent fiber and lignin during sunrrner than during winter, reflect-
ing the superior quality of summer forage. Estimates of food intake by
moose vary greatly in the literature, although there is considerable
evidence indicating that a greater quantitv of food is consumed during
summer than during winter. Dry matter consumed by adult females was
estimated to be three to four times greater during sunrrner than during
winter. Increased rumen fill and decreased food intake during winter
apparently result from slow passage of low quality food which restricts.
additional food intake, and from voluntary reduction of forage consumption.
Volatile fatty acids (VFA) produced by rumen microbes by fermenta-
tion of dietary carbohydrates and prote,ins constitute approximately 57
percent of the digestible energy of rurrdnants. VFA production, which is
directly related to food quality, was determined seasonally on free-
ranging moose in interior Alaska using the "zero time rate" method.
Production rates varied from a mean low of 18 eq VFA/ml rumen liquor/
hr durinp: winter to 60 eq VFA/ml rumen liquor/hr during summer.
Moose undergo a large seasonal change in body ~•eight which corre-
sponds closely to seasonal rates of VFA energy production. Metabolizable
energy (ME), calculated from estimated VFA production, increased from
7,300 kcal/day in females during winter to 20,900 kcal/dav in lactating
moose during summer. It was estimated that approximately 6,000 kcal/day
of ME was required for BMR. During winter an estimated average of 3,900
kcal/day was obtained from catabolism of fat and protein reserves to
meet the energy requirements not provided by forage, while during summer
7,600 kcal/day of fat and protein were deposited.
23
A review of effects of malnutrition on rumen function shows that a
decrease in food quantity or quality depresses microbial populations
and rates of fermentation.
The value and practical application of using various parameters of
rumen fi.mction to evaluate nutritional status of ruminants and quality
of the habitat are discussed.
ACKNOWLEDGMENTS
Photographs and technical equipment for constructing the vegetation
type map were generously supplied by the State of Alaska Lands Division.
SpeCial thanks are due Larry L. Johnson, temporary, for exclusive prepa-
ration of the type map. Dorothy Simpson, botanist and secretary, ADF&~,
and Ronald Severns, temporary, provided expertise, initiative, and
excellent company during long, sometimes uncomfortable days conducting
vegetation surveys. Institute of Northern Forestry personnel, especially
Charles Cushwa, Nonan Noate; and Les Viereck, provided necessary techni-
cal and analytical assistance associated with vegetation sampling._ Les
Viereck and Dorothy Simpson identified plant material from moose rumen
contents. Numerous ADF&G employees, including Carol Ericson, Wayne
Heimer, Edward Kootuk, Georganna Ranglack, John Trent, and Mike Vierthaler,
assisted in collecting material at various times during energy require-
ment and rumen fermentation studies. ADF&G biologists Albert Franzmann
and Paul Arneson permitted use of the Kenai Moose Research Center facility
and provided assistance irt testing radio collars and conducting energy
requirements studies. . The above individuals have made this study both
possible and enjoyable, and their valuable contributions are gratefully
acknowledged.
LITERATURE CITED
Anderson, J. P. 1959. Flora of Alaska and adjacent parts of Canada.
Iowa State Uni v. Press , Ames. 543 pp.
Andreasen, G. E., C. Wahrhaftig, and I. Zietz. 1964. Aeromagnetic
. reconnaissance of the east-central Tanana lowland, Alaska. US~S,
Washington. 3 pp.
Benninghoff, W. S. 1952. Interaction of vegetation and soil frost
phenomena. Arctic 5:34-44.
Bishop, R. H. 1969. Preliminary review of changes in sex and age ratios
of moose and their relation to snow c9nditions on the Tanana Flats,
Alaska. Paper presented at 6th Annu. N. Am. Moose Committee Meeting,
Feb. 3-5, Kamloops, B. C. 14 pp. Xerox.
Black, R. F. 1958. Lowlands and plains of interior and western Alaska
in H. Williams, ed. Landscapes of Alaska. Univ. Calif. Press,
Berkeley. pp. 76:...81.
24
Coady, J. W. and W. C. Gasaway. 1972. Rumen function and energy pro-
duction of moose in interior Alaska. In R. B. Addison ed. Proceed-
ings of the 8th North American Moose Conference and Workshop.
Queen's Printer for Ontario. pp. 80-104.
Cole, G. F. 1963. Range survey guide. Grand Teton Natl. Hist. Assoc.
Moose, Wy. 22 pp.
Cushwa, C. T. and J. W. Coady. 1973. Moose food habits in Alaska, a
preliminary study using stomach contents analysis; MS 21 pp.
Xerox.
____________ ., S. A. Liscinsky, R. F. Harlow and M. J. Puglisi. 1973.
Rumen analysis in white-tailed deer management -development, use,
and evaluation of a procedure. MS 40 pp.
Drury, W. H!, Jr. 1956. Bog flats and physiographic processes in the
upper Kuskokwim River region, Alaska. Contrib. Gray Herb. No. 178,
Harvard Univ. 130 pp.
Dutro, J. T. and T. G. Payne. 1957. Geological map of Alaska. USGS,
Scale 1:2,500,000.
Gasaway, W. C. and J. W. Coady. 1973. Review of energy requirements
and rumen fermentation in moose and other ruminants. Int. Symp.
on Moose Ecology, Quebec City. March 1973. 37 pp.
Hanson, H. C. 1951. Characteristics of some grassland, marsh, and
other plant communities in western Alaska. Ecol. Monogr. 21(4):
317-378.
1953. Vegetation types in northwestern Alaska and
comparisons with communities in other arctic regions. Ecology
34(1) :111-140.
Hulten, E. 1968. Flora of Alaska and neighboring territories.
Stanford Univ. Press. 1,008 pp.
Johnson, P. L. and T. C. Vogel. 1966. Vegetation of the Yukon Flats
region, Alaska. CRREL Research Report 209. Hanover, N. H. 53 pp.
Johnson, P. R. and C. W. Har.tman. 1969. Environmental atlas of Alaska.
Inst. of Arctic Env. Eng. and Inst. of Water Res. Univ. Alaska,
College. 111 pp.
Larsen, J. A. 1965. The vegetation of the Ennadai Lake area, N.W.T.:
Studies in subarctic and arctic bioclimatology. Ecol. Monogr.
35(1) :37-59.
Ohmann, L. F. and R. R. Ream. 1971. Wilderness ecology: virgin plant
communities of the Boundary Waters Canoe area. USDA Forest Serv.
Res. Paper NC-63.
25
Ritchie, J. C.
Paper 3.
1959.
56 PP·
The vegetation of northern Manitoba. AINA Tech.
Spencer, D. H. and E. F. Chatelain. 1953.
of the moose in southcentral Alaska.
Conf. pp. 539-552.
Progress in the management
Trans. 18th N. Am. Wildl.
Viereck, L~ A. 1970a. Forest succession and soil development adjacent
to the Chena River in interior Alaska. Arctic and Alpine Res.
2"(1) :1-26.
1970b. Soil temperatures in river bottom stands in
interior Alaska. In Ecology of the subarctic regions, Proc.
Helsinki Symp. (Ecol. and Conser. No.1). Paris, UNESCO. 364 pp.
(in press). Wildfire in the taiga of Alaska. J. Quant.
Res. 75 pp.
Viereck, L. A; and E. L. Little, Jr. 1972. Alaska trees and shrubs.
U.S. Dept. Agr. Handbook 410. 265 pp.
Wahrhaftig, C. 1965.
Prof. Paper 482.
PREPARED BY :
John W. Coady
Game Biologist
SUBMITTED BY :
Richard H. Bishop
Physiographic divisions of Alaska. Geol. Surv.
U. S. Gov. Printing Office, Wa5h. 52 pp.
APPROVED BY:
~~·smz~;:t
·Research Chief, Di visio of Game
Regional Research Coordinator
26
State:
Cooperator:
Project Nos:
Job No:
JOB PROGRESS REPORT (RESEARCH)
Alaska
John W.
W-17-4
W-17-5
1.8R
Coady
& Project Title: Big Game Investigations
Job Title: Snow Characteristics in
Relation to Moose
Distribution in Interior
Alaska
Period Covered: July 1, 1971 to June 30, 1973
Sill1MARY
This report describes major activities undertaken between February
1971 and June 1973. This research project was initiated in February
1971 during a winter of record snowfall in interior Alaska. Substantial
winter mortality of moose permitted collecting numerous data on sex and
age, body weights and measurements, reproductive status of females, and
bone marrow fat content of moose in the Interior. Collection of these
data has continued to the present as opportunity has permitted. Both
NRC inscruments and the Swiss Rammsonde Penetrometer have been used
since November 1972 to monitor physical characteristics of the snow
cover at various sites in Game Management Units 20A and 20B. Frequent
aerial surveys and ground track counts hav~ been conducted near snow
study sites to relate moose movement and distribution to snow conditions.
Although rarely used in biological studies, the ease, accuracy, and
properties of the snow measured by the Rammsonde appear to make the
instrument useful for assessing severity of snow conditions for large
ungulates. A limited radio telemetry program initiated in November 1972
provided additional information regarding moose movement in response to
snow conditions and habitat use, and indicated that telemetry may be a
useful tool for studying certain aspects of moose behavior in interior
Alaska.
i
Summary ..
Background.
Objectives ..
Procedures.
CONTENTS
Production, Survival and Physical Condition of Moose .
Snow Measurements. • •.
Radio Telemetry. . • . • . . . . . • . . .
Findings and Conclusions. . .....••.•.
Production, Survival and Physical Condition of Moose •
Moose-Snow Relationships •
Radio Telemetry. • . .
Acknowledgments .
Literature Cited •••
BACKGROUND
i
1
2
3
3
4
8
10
10
30
44
45
46
Moose (AZces aZces) are Holarctic in distribution (Rausch, 1963),
occurring in several Eurasian countries, Canada, the conterminous United
States, and Alaska. Four Eurasian races (Heptner et al., 1961) and four
North American races (Hall and Kelson, 1959) of moose are recognized.
The Alaskan moose (A. a. gigas) is of pre-Wisconsin age, remains having
been found in Illinoian beds in the "Cripple Creek sump" near Fairbanks
(Pewe and Hopkins, 1967).
Moose are expanding their range throughout North America (Kelsall,
1972; Kelsall and Telfer, 1973). In Alaska, moose are widespread within
the boreal forest zone (Alaska Dept. of Fish and Game, 1973), although
many reports suggest they are more common beyond tree line in several
areas than in previous years (Rausch, 1951; Bee and Hall, 1956; Lutz,
1960; Pruitt, 1966; Chesemore, 1968; and LeResche et al., 1973). North-
ward dispersal of moose may be due in part to an increase in riparian
climax vegetation resulting from gradual Holarctic warming trends during
the last half century (Leopold and Darling, 1953). This apparent expan-
sion may also result from recent increased human activity in northern
regions, the-reby increasing opportunity for sighting animals (Kelsall,
1972).
Moose play an important economic and cultural role in Alaska.
Between 1963 and 1972 an average of 7500 moose per year were reported
killed by hunters. In 1971 alone, over 8800 moose were reported killed,
1070 of which were from the Fairbanks region (Game Management Unit 20) .
Thousands of recreationists photograph and observe moose each year. The
extensive distribution, large numbers, and relatively visible nature of
the species has made moose a symbol of Alaskan wildlife.
Since statehood in 1959 the Alaska Department of Fish and Game has
actively engaged in collecting information in interior Alaska relating
to moose biology. Major emphasis has been pl-aced on extensive aerial
surveys during fall to document changes in productivity, to assess the
effect of hunting on bull-cow ratios, to determine survival of moose to
1
1.5 years of age, and to document ~hanges in relative abundance and
distribution of moose. Annual aerial surveys have been conducted in
selected areas during spring to assess survival of moose to 1 year of
age, and to monitor changes in relative abundance and distribution of
moose. Harvest statistics and basic life history information have also
been collected. In spring 1966 a moose calf tagging program was initiated
on the Tanana Flats south of Fairbanks to help determine distribution,
movement, and population identity of moose calving in the area. Between
1966 and 1969 over 800 moose calves were tagged, and locations of tagged
moose continue to be recorded as sightings are made.
Major contributions to moose studies in interior Alaska have been
made by Robert A. Rausch (Rausch, 1967, 1971; Rausch and Bishop, 1968)
and Richard Bishop (Bishop, 1969, 1970; Bishop and Rausch, 1973).
Together these individuals conducted and directed many early studies of
moose in interior Alaska. Theirwork has provided the background for
and continues to provide ·guidance in developing current moose studies.
\
In February 1971, a winter of record snowfall in interior Alaska, a
moose research program was initiated at Fairbanks to further id~ntify
and quantify major control factors affecting moose populations. Basic
emphasis of the program centers around effects of certain relationships
between snow and range conditions on the production, survival, and dis-
tribution of moose in interior Alaska. Information ·obtained from this
project will hopefully contribute to efficient management of. moose in
interior Alaska, where growth of human populations and increased demands
on wildlife and land resources are expected.
OBJECTIVES
The objectives of this study are 1) to obtain certain data pertain-
ing to production, survival, and general condition of moose in interior
Alaska; 2) to evaluate the morphological adaptation to snow of various
sex and age class moose; 3) to monitor distribution, survival, and
productivity of moose in relation to char.acteristics of the snow cover
in interior Alaska; 4) to test different instruments and techniques for
evaluating the severity of winter conditions to moose; and 5) to determine
the influence of snow and habitat on the seasonal movement and distribu-
tion patterns of radio-collared moose breeding in the Little Chena
drainage, and to test the feasibility of using biotelemetry to study
movements of moose in interior Alaska. ·
The following data were collected:
1) Body weights and measurements of pre-and post-natal moose;
2) Chest height and foot load of post-natal moose;
3) Reproductive status of females over 1 year of age;
4) Percent femur marrow fat;
2
5) Sex and age of moose dying from both malnutrir.ion and unnatural
causes;
6) Snow depth, hardness, density, temperature, and Rammsonde hard-
ness at various sites in relation to distribution and abundance·
of moose;
7) Visual s~arch time, location, habitat selection and activity of
radio-collared moose.
PROCEDURES
Production, Survival and Physical Condition of Moose
Moose dying from natural (malnutrition, predation) and unnatural
(highway and railroad collisions, shooting) causes between February 1,
1971 and June 1, 1973 within 100 miles of Fairbanks were examined. Moose
killed on highways were retrieved with a truck, while specimens from
animals killed on the railroad were collected with a rail-car. Snow
machines, fixed-wing aircraft, and helicopters were used to collect
animals or specimens in remote areas. Private individuals also collected
numerous specimens.
Post-natal body weights were measured with a commercial truck
in Fairbanks or with a spring scale_suspended under a helicopter.
body weights were measured with a hand-held spring scale.
·The following measurements were obtained when possible:
1) Heart girth: measured immediately behind front legs;
2) Total length: measured along contour of body from hairless
portion of nose to base of tail;
scale
Fetal
3) Total height: measured along contour of body from tip of hoof
to top of shoulder or scapula;
4) Chest height: measured from tip of hoof to brisket or sternum,
with leg in "normal" position relative to body;
5) Hind leg: measured from tip of hind hoof to hock or tuber calcis;
6) Knee: measured from tip of front hoof to middle of knee or
carpus;
7) Foot load: determined by measuring area of four feet and divid-
ing total area by body weight, according to the procedure
described by Kelsall and Telfer (1971).
Only heart girth and body con tour length were measured on pre-natal
animals.
3
Reproductive tracts of females over 1 year old were examined for
pregnancy. Ovaries were collected and prese:r:ved in formalin.
Incisors were collected from animals over 1 year old, and the age
determined by examining cementum growth layers.
Percent fat in femur or tibia marrow was determined by drying marrow
from fresh or frozen bones at 65°C to constant weight according to a
method developed by Neiland (1970). Although marrow is composed of
water, fat, and non-fat residue, the non-fat residue is small (2-6 per-
cent of total weight), and the dried marrow is .. assumed to consist entirely
of fat.
Unless otherwise stated, 0.05 was the probability level at which.
the null hypothesis was rejected.
Snow Measurements
Methods of measuring properties of a snow cover have been described
by several authors (Klein et al., 1950; Benson, 1962; Keeler, 1969; Test
Lab, 1970; and others). Two similar sets of instruments, a National
Research Cbuncil of Canada (NRC) kit and a USA Cold Regions Research and
Engineering Laboratory (USACRREL) kit have been used to measure tempera-
ture, density, and hardness of a snow cover. However, modified snow
study kits have also been used (Richens and Madden, 1973). These
measurements are generally obtained in "pit" studies, in which a trench
is dug in the snow to ground level. Thickness, temperature, density,
hardness, and sometimes crystal type and size of major strata are
recorded; Snow samples or measurements are generally taken iri a horizon-
tal plane, although vertical as well as horizontal hardness measurements
should be made (Pruitt, 197la). The International Workshop on Rangifer
Winter Ecology (Pruitt, 197la) has recommended measuring the thinnest
distinct strata which a given instrument size will allow.
Depth of snow cover is probably the most common and important
measurement obtained in studying snow ecology of moose. In addition to
ease of measurement, snow depth provides a measure of the thickness of
the medium through which an animal must move if not supported by the
snow .. Depth of snow or thickness of strata can be measured with any
conveniently calibrated probe. In addition, in interior Alaska 5 em
diameter stakes, clearly calibrated at 30.5 em (12 in) intervals, have
been permanently located in remote or inaccessible areas to measure snow
depth from fixed wing aircraft. Depth can consistently be estimated
within 3 to 5 em of the actual snow depth, although this method has the
disadvantages of limiting measurements to the number of stakes at a
study site, and limiting study sites to relatively open areas where the
aircraft may be flown near ground level. Snow depths relative to
anatomical features of moose also provide a useful and reasonably
accurate estimate of snow depth from the air.
Snow temperatures of each substrate or at intervals on the pit
wall, beginning at ground level or in the subnivian space and ending
within 2 em of the surface, may be measured. However, the International
4
Workshop on Rangifer Winter Ecology (Pruitt, 197la) has questioned the
significance of measuring snow temperature in Rangifer research, and has
recommended limiting measurements to ground level and air temperatures.
While a relationship between snow temperature and moose behavior has
been alluded to by Des Meules (1964), the ease and speed of temp-erature
measurement in pit studies and its possible signtficance to moose
behavior probably merit its continued measurement. Measurements may be
made with either an alcohol or bimetallic thermometer.
Density, determined by weighing a known volume of snow, is probably
the most widely used index of snow type, and under certain snow condi-
tions it may be correlated with hardness (Keeler and Weeks, 1967; Bilello
et al., 1970). Increased density presumably causes increased drag on
legs or the body of ungulates during movement, and thereby inhibits
locomotion. Several snow cutters for obtaining snow density samples are
available. The NRC kit employs two 250 ml snow cutters; one for soft
and one for hard snow, while the USACRREL kit uses 500 ml sampling tubes.
Swedish workers use a Swedish Army density "box" which reportedly gives
reliable results because of its large 1,000 cm3 volume (Fruit t, 19 7la) .
In interior Alaska a 650 cm3 plastic cylinder has been used with ·
satisfactory results.
Snow hardness reflects the degree of bonding between crystals and
in most types of snow increases as density increases and/or snow tempera-
ture decreases (Gold, 1956). In addition to snow depth, hardness is
probably the most critical parameter of a snow cover to ungulates since
it reflects the force which must be exerted to move legs or body through
the snow, and the ability of the snow to partially or fully support the
animal. NRC and USACRREL snow hardness gauges are similar, and consist
of a spring-loaded push rod with provision for mounting discs of different
areas on one end and a calibrated gauge on the other end. The disc is
pressed against a snow surface and the maximum stress associated with
the initial collapse of the snow structure is noted on the gauge. By
using a high and low range gauge and different sized discs, hardnesses
of 0 to 100,000 g/cm2 can be measured. Useful modifications to the
instrument developed in Sweden and.now used by Pruitt (per. comm.)
include a ratchet which retains the calibrated gauge at the extended
position reached at the instant of snow collapse, thereby providing more
accurate measurements.
Snow hardness may ·also be measured with a cone penetrometer,
commonly referred to as a Swiss Rammsonde. The instrument and its use
have been described by several workers (Bader et al. , 19 39; Benson> 1962;
Keeler, 1969; Test Lab., 1970; and others). Basically, it consists of a
hollow steel shaft with a 60° conical tip 4 em in diameter and 3. 5 em
high. A solid rod mounted on top of the steel shaft guides a hammer
. which is dropped from a measured height. The height of the drop, weight
·of the entire instrument, .and depth of penetration may be related to the
resistance of snow to penetration by·the cone using the following
formula:. R = Whn + W + Q, where R = ram hardness number or resistance --x
to penetration, W = weight (kg) of penetrometer. The equation ignores
friction between the cone and snow arid elasticity in the penetrometer.
5
However,.error is small, especially for snow of relatively low hardness
(Keeler, 1969; Benson, per. comm.).
The ram hardness number, R, indicates the resistance (kg) of a
layer of snow to penetration by the cone of the penetrometer. In prac-
tice it may be useful to determine the ram hardness value for the total
snow depth. To do this an integrated ram hardness number, Ri (kg-em),
is calculated by multiplying each depth increment (em) times its ram
hardness m.nnber,. R (kg), and summing the values from the snow surface
to ground level or to any given depth. The irttegrat·ion indicates the
work done by the penetrometer as it moves through the snow to a given
depth.
The Rammsonde can be used in several ways. It can rapidly distin-
guish different strata and provide a ram hardness profile or an integrated
ram hardness value of the total snow cover without digging a pit.
Rammsonde measurements are less subject to operator error than are NRC
or USACRREL snow hardness values (Benson, 1962). Limitations to this
procedure include lack of resolution at low snow hardness. However, a
modified 120° cone, 10 em in diameter, has been satisfactorily used by
Abele (1968) in soft snow.. The hardness number obtained with· the large
cone is divided by_ a factor of 10 to obtain the approximate ram· hardness
value of the standard cone (Test Lab, 1970).
Rammsonde hardness numbers can be correlated with other derived
snow measurements under most temperature and snow conditions, and with
the support capacity of snow. Bull (1956) and Keeler (1969) have
correlated ram hardness values with snow densities, while Abele (1963)
has related ram values to compression strength or hardness. Abele et al.
(1965, ·1968), Wuori (19o2, 1963) and others have related ram hardness to
vehicle support capacity of snow roads and runways.
While the Rammsonde penetrometer has been used extensively to study
mechanical properties of a snow pack, it has been used rarely in biologi-
cal applications. Other than Lent and Knutson (1971) working with musk-
oxen (Ovibos moschatus), Coady (this report) working with moose, and
some investigators in Canada and Scandinavia working with reindeer
(Rangifer sp.) (c.f. Pruitt, 197lb), the instrument has not been widely
used in studies of ungulate snow ecology. Additional measurements and
experience are certainly required to evaluate the usefulness of the
Rammsonde penetrometer in biological studies. Ease, speed, and consis-
tency of identifying stratigraphic horizons and measuring hardness of a
snow cover may make the Rammsonde a potentially valuable instrument for
assessing the resistance to movement through or the support capacity of
snow.
Both NRC and Rammsonde snow measurements were recorded at each
station on a data form (Fig. 1). Site characteristics, weather, general
snow conditions, presence or absence of moose in the vicinity, and if
moose are present, the depth of foot penetration into the snow were
recorded. NRC measurements consisted ofweight of snow, hardness,
temperature, and crystal type (optional). in each snow layer on the pit
wall. Rammsonde measurements were obtained by noting weight of hammer,
6
Fig. 1. Alaska Department of Fish and Game data form used to record National
Research Council (NRC) of Cailada and Swiss Rammsonde Penetrometer
snow measurements.
ALASKA DEPARTMENT OF ·FISH AND GAME SNOW SURVEY
Station
Altitude Exposure
Vegetation
.Date Time Observer
Air Temp Weather
Snow Depth Snow Surface
Moose Present Track Depth
NRC Measurements
Depth Gross Wt Density_ Hardness Temp Crystals Remarks
Rammsonde ·Measurements
Penetration Resistance
Wt Ht (1) (2) (3) (4) (5) (1) (2) (3) (4) ·(5)
7
height of hammer drip, and total depth of Rammsonde penetration after
each hammer drop (recorded in a vertical coltnnn). Ramms.onde measurements
were repeated five times at each station. The resistances for each
increment of Rammsonde penetration and for each trial were calculated
at a later date.
Trends in snow severity for moose in interior Alaska were examined
by plotting weather bureau records of snow depth on the ground in
Fairbanks versus month throughout the winter, and measurtng the area
under the curve with a planimeter. A similar procedure could be used
to evaluate temperature severity. While weather bureau measurements may
not indicate actual conditions on winter moose range, they probably
reflect relative differences between years and long:..term trends.
Depth, temperature, density, .hardness (NRC hardness gauge, and
Rammsonde hardness of the snow cover) and relative abundance of moose
were monitored at weekly to monthly intervals in different habitats in
the Chatanika drainage, the Chena drainage, the Tanana Fl.its, and the
north side of the Alaska Range foothills. The major study area is
located near 40 mile Steese Highway (Chatanika drainage), where rela-
tionships between altitudinal moose movements and snow conditions were
monitored during the winters of 1971-'72 and 1972-73. The seven day.
total (counted daily) of fresh moose tracks crossing a one-half mile
long transect in the Chatanika River valley was recorded between
November and May. The valley is located at 245 m elevation, and
represents typical winter ·riparian moose habitat. The number of moose
counted during frequent intensive aerial surveys in a 75 km 2 drainage
above the_ valley transect was also recorded. The upland site ranges
from 550 to 670 m elevation and consists of mixed conifer and deciduous
trees and shrubs which characteristically support modest numbers of
moose during summer and fall in interior Alaska. Snow measurements were
obtained in shrub communities in the upland site, and :in shrub, deciduous
tree, conifer tree, and grass communities in the valley site.
Radio Telemetry
Six a:dult female moose were radio collared in the 15-year-old
Elliott Creek burn along the upper Little Chena River (elevation 300-
700 m) during November 1972. Collaring procedures and transmitter
specifications are on file at the Alaska Department of Fish and Game
office in Fairbanks, and will not be reported here. Collared animals
were located from the air at two-to ten-day intervals, and the location
of individual moose was plotted on one inch to one mile USGS maps or on
four inch to one mile vegetation type maps. Habitat selection (herbaceous
bog, heath bog, shrub, deciduous tree, conifer tree), activity (bedded,
standing), and time spent visually searching for the animal after her
location was determined electronically were recorded on data forms (Fig.
2). Snow depth in the Elliott Creek burn was monitored from the air
using permanently located calibrated stakes. Monthly aerial moose
surveys were conducted in the Elliott Creek burn ·between November and
March.
8
Fig. 2. Alaska Department of Fish and Game d·ata form used to record
observations of radio collared ti:10ose in GMU 20A and 20B.
RADIO~COLLARED MOOSE OBSERVATIONS
Area Snow
Date
Pilot/Observer
Temp
Weather
Wind
Animal 1 2 3 4 5 6·
Detect
Signal?
Locate?
Visually
Time of
Day
Visual
Search
Time
Habitat
Activity
Grouping
9
FINDINGS AND .CONCLUSIONS
Production, Survival and Physical Condition of Moose
Weights and. Measurements: Weights and measurements were obtained
from 22 moose fetuses collected in interior Alaska (Table 1). Date of
death is recorded to the nearest day or month, when known. Five fetuses,
ranging in weight from 13.6 to 17.2 aDd averaging 15.2 kg, were collected
on the Tanana Flats on May 24, 1971. Calving was underway. at this time,
and therefore the above weights are considered to represent the approxi-
mate birth weight of moose calves in the area.
Growth rates for moose fetuses have been recorded by Edwards and
Ritcey (1958) in British Columbia, by Rausch (1959) in Alaska, and by
Markgren (1969) in Sweden. Growth rate of fetuses reported in Table 1,
based on total contour length and date of death,when known, agree
closely with that reported by Rausch.
Birth weights of 6 to 16 kg have been reported for moose in the
USSR (Knorre, 1961); of 11.2 kg for moose in Michigan (Verme, 1970)·, and
of 11.3 to 15.9 kg for moose in Alaska (Rausch, 1959). Markgren (1966)
measured weights of 11.5 and 13.5 kg for two 4-day-old moose in Sweden.
The average weight of 15.2 kg reported in this study for near-term moose
fetuses agrees most closely with the findings of Rausch; and is somewhat
greater than the weights recorded by other investigators.
Knorre (1961) found an average birth weight ot 12.8 kg for single
and 10.3 kg for twin calves. Individual weights ·of the one set of twins
near term in this study were similar to weights of the three single
calves (Table 1).
Weights and measurements were obtained from .approximately 25 moose
calves under 1 year of age (Table 2). Based on limited data presented
in this report, birth weight (see Table 1) increased over 2. 5 times by
four weeks, over 4.5 times by six weeks, and by approximately 10 times
by 6 to 12 months of age.
The extremely rapid growth rate of moose calves has been noted by
many workers. Rausch (1959) also reported that moose calves in Alaska
increase their birth weight by a factor of 10 after six months. Verme
(1970) found that calves in Michigan tripled their birth weight by.four
weeks and weighed 159 kg by six months of age. In Alberta Blood et al.
(1967) found average weights of 197 and 174 kg for male and female .
calves, respectively, after six months. Weights of moose calves have
also been reported by Denniston (1956), Dodds (1959), Knorre (1961) ,
Peek (1962), and Markgren (1966). 'Earlier studies have been summarized
by Peterson (1955).
Weights and measurements from approximately 55 moose older than 1
year were obtained during winter and spring (Table 3), sununer (Table 4),
and fall (Table 5). During each period maximum body weight and skeletal
measurements were reached after approximately three years of life (Figs.
3-7) • These age specific data suggest that moose, at least females, in
10
Table 1. Weights and measurements of moose fetuses from interior Alaska
(GMU 20A and 20B).
Total
Contour Length Heart Girth Date of Age of
Sex Wt (k~} (em) (em) Death Cow
F 0.64 33.0 20.3 12/70 4
M 3.86 66.0 38.1 3/12/71 11
F 2.28 52.7 31.1 2
F 1.81 45.7 14
M 2.94 63.5 34.3 3/71 14
F 0.79 29.8 18.4 10
M 1.02 49.5 30.5 11
F 4.08 62.2 33.7 3/71 13
~ (twin) 1.36 41.9 26.7
(twin) 1.13 40.6 27.2
r; (twin) 0.57 33.7 18.4 13
I
·F t~ (twin) 0.91 33.7 19.1
M 3.40 62.2 34.3 3/20/71 11
M 4.98 69.9 40.6 4/8/71 15
F 0.24 26.6 10
M 3.44 61.1 33.0 16
F 4.54 69.9 38.7 16
F 17.23 106.7 55.9 5/24/71 11
F 13.61 100.3 53.3 5/24/71
M 14.51 96.5 53.3 5/24/71 2
G (twin) 15.87 96.5 53.3 5/24/71 8
F (twin) 14.97 95.3 52.1 5/24/71 8
11
Table 2. Weights (kg) and measurements (em) of moose calves from interior
Alaska (GMU 20A and 20B).
Age and Measurement No. Mean s. D. S. E. Range
4 weeks
Weight 2 41.5 . 28.6-54.4
6 weeks
Weight 1 70.0
Heart girth 1 88
Total length 1 128
Shoulder height 1 86
6-12 months
Weight 23 157 25 5 113-238
Heart girth 17 143 15 4 127-186
Total length 22 204 11 2 173-213
Shoulder height 21 148 16 4 122-194
Chest height 21 84 8 2 66-95
Hind foot length 20 63 5 1 51-74
12
Table 3. Weights (kg) and measurements (em) of male and female moose over
1 year of age during winter and spring in interior Alaska (Gt-ru
20A and 20B) .
·Age and Measurement No. Mean S. D. S. E. Range
1 ear
Weight 1 254
Heart girth 1 203
Total length 1 254
Chest height 1 94
Hind foot length 1 69
2 ears
Weight 2 356 295-417
Heart girth 3 195 19 .11 173-211
Total length 4 275 18 9 262-302
Total height 5 183 13 6 163-:-198
Chest height 5 101 4 2 97-105
Hind foot length 6 71 4 2 66-76
3 ears
Weight 1 279
Total length 1 254
Shoulder height 1 175
Chest height 2 97 97-97
Hind foot length 2 71 71-71
4 ears
Weight 2 368 361-374
Heart girth 2 196 194-198
Total length 2 271 270-272
Total height . ·2 181 17 5-187
Chest height 2 103 101-104
Hind foot length 2 82 79-85
6 ears
Weight 1 385
Heart girth 1 188
Total length 1 254
Shoulder height 1 183
Chest height 2 93 91-94
Hind foot length 2 65 61-69
13
Table 3. Continued.
Age and Measurement No. . Mean S. D • S. E. Range
7-8 ears
Weight 2 368 361-374
Heart girth 2 192 192-192
Total length 2 277 274-280
Total height 1 177
Chest height 1 108
Hind foot length 1 77
10-11 years
Weight 5 351 69 34 266-435
Heart girth 3 177 4 2 173-180
Total length 2 281 269-292
Shoulder height 6 182 12 6 163-196
Chest height 5 102 5 2 97-109
Hind foot length 5 63 5 3 61-71
13+ ears
Weight 2 325 313-336
Heart girth 3 179 8 4 175-188
Total length 4 274 13 7 259-290
Shoulder height 5 179 11 5 165-193
Chest height 5 100 2 1 97-102
Hind foot length 12 68 4 1 61-74
14
Table 4. Weights. (kg) and measurements (em) of cow moose over 1 year
of age during late June in interior Alaska (GHU 20A).
Age and Measurement
1 ear·
Weight
Heart girth
Total length
Shoulder height
Chest height
2 ears
Weight
Heart girth
Total length
Shoulder height
. Chest height
3 ears
Weight
Heart girth
Total length
Shoulder height
Chest height
4 ears
Weight
Heart girth
Total length
Shoulder height
Chest height
6 ears
Weight
Heart girth
Total length
Shoulder height
Chest height
10-11 years
Weight
Heart girth
Total length
Shoulder height
Chest height
No.
1
1
1
1
1
3
3
3
3·
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
Mean
15
227
156
203
151
92
395
177
265
180
112
463
204
272
188
110
390
172
273
184
113
367
186
284
188
105
413
191
269
182
107
·Range
381-408
174-182
242-278
177-183
106-118
376-449
188-194
268-269
174-190
106-107
Table 5. Weights (kg) and-measurements (em) of male and female moose
over 1 year of age during October in interior Alaska (GMU 20A
and 20B).
Age and Measurement No. Mean Range
3 ears
Weight 1 490
Heart girth 2 216 202-230
Total length 2 295 276-314
Shoulder height 1 209
Chest height 1 107
Hind foot length 1 88
4 ears
Weight 3 524 501-546
Heart girth 3 213 210-214
Total length 3 . 289 270~306
Shoulder height 3 188 183-192
Chest height 3 111 107-118
5 ears
Weight 1 512
Heart girth 1 186
Total length 1 304
Shoulder height 1 192
Chest height 1 106
Hind foot length 1 79
7 ears
Weight 1 458
Heart girth 2 209 204-214
Total length 2 275 260-289
Shoulder height 1 172
Chest height 1 108
Hind foot length 1 82
10-11 years
Weight 1 517
Heart girth 3 208 204-212
Total length 3 306 297-311
Shoulder height 1 180
Chest height 1 106
Hind foot length 2 86 83-89
16
Fig. 3. Hind foot and total body length of male and female moose obtained
in GMU 20A and 20B during winter and spring, 1971 to 1973.
300~~--~----4
CD CD CD
200
E
(.) _..,
..c
+-
Ol c
(J)
_J 100
0
+-
~
+-
0
~
'"0 c
I
CD ® ®
(I I l. 3 &-8
Age (Year.s}
17
-
Fig. 4.
400
Heart girth and total body weight of male and female moose
obtained in GMU 20A and 20B during winter and spring, 1971 to
1973.
CD
CD
CD
0 .... _ _,_ ___ _,_ ___ ..&... ___ ....__, I I I I I ,_I_.___.
I i I I I 2 3 ,_8 I0-1/ I 3+
Age (Yea. r s)
I
18
19
Fig. 6. Total body weight and body length of male and female moose
obtained in GMU 20A and 20B during fall, 1971 and 1972.
f f (j) ® 300
¥
,...... s
(J
'-'
p::
~ z
1>-4
...:! 200
~
E-<
0
E-<
'
100 ~l '1-_j
I I
I ~ CD (j) l ([)
CD J 400
I ,...... i blJ ..,: I
E-< I
l t5 ' H ~ ~
>-<
I
I t=l ! 0
~ i
I ~ 1
200 l I
!
i
I I
I{ I 1/ I
3 4 5 7 . /J 10-11
AGE (YEARS)
20
s
tJ
p::
~ z
r.-:1 ....
N
f-' !;;;1
t)
E-<
I
i
I
I
I
1 2 3 5
AGE (YEARS)
6 10-11 13+
N
0 >
~ p..
N
0
bd
the study area may reach maximum body mass and skeletal dimensions dur-
ing their third year.
Body mass or weight is a widely used measure of growth rate and
indicator of physical condition (Klein, 1970). Nevertheless, skeletal
measurements better reflect growth rate since they are not subject to
short-term fluctuations associated with fullness of the digestive tract,
seasonal accumulation .and utilization of fat reserves, etc. (Klein, 1964,
1965). In addition, skeletal measurements are generally easier to obtain
than body weight from large animals.
Total length, and to a lesser extent hind foot length, and shoulder
height best reflected a pattern of age specific growth. Heart girth
involves measurements of the skeleton as well as overlying muscle and
fat, and therefore reflects the mass of the animal more closely than
skeletal growth (Brandy et al., 1956). Chest heights were recorded to
evaluate the potential performance of the animal in deep snow for this
study.
Moose have been reported to reach maximum body size within two to
four years in other areas. Blood et al. (1967) noted that moose in
Alberta increased in weight until three and one-half years of age, or
perhaps longer, while Verme (19 70) found that females in Hichigan reached
maximum size in two and. one-half years, and males increased in size
until three and one-half years old. Rausch (1959) found that female
moose in southcentral Alaska grew very little beyond wear age class III
(two to four years).
However, other workers have reported that moose grow in both weight
and skeletal size for several years. Skunke (1949) noted the moose in
Sweden increase in weight until 7 to 10 years of age, and LeResche and
Davis (1971) indicated that growth of moose on the Kenai Peninsula in
Alaska may continue throughout the life of the animal. After reviewing
the European and American studies, Jordan et al. (1970) concluded that
body growth continued until year six in females and year 11 in males.
In interior Alaska maximum body weights occurred during fall. The
average weight for two bulls and five cows collected during mid-October,
well into the rut, was 507 kg. The heaviest animal was a 4~year-old
bull weighing 546 kg, while the next heaviest was a 4-year-old cow
weighing 524 kg (Table 5).
Body weights of moose reported from other areas are generally less
than those cited here. The heaviest bull and cow weighed by Blood et al.
(1967) in Alberta were 478 and 429 kg, respectively, vJhile Verme (1970)
found a maximum weight of 506 and 385 kg for a bull and cow in Hichigan,
respectively. Rausch (1959) noted that few bulls exceed 545 to 635 kg
in Alaska, and reported a weight of only 517 kg and a body length of 287
em for the largest bull he examined. LeResche and Davis (1971) reported
a weight of 445 kg for the largest cow handled at the Kenai Hoose
Research Center, Alaska.
Moose in interior Alaska apparently experience considerable seasonal
22
.fluctuation in body weight. Average body weights for moose older than
three years (see Tables 3, 4, 5) weue 338 kg in December through May,
409 kg in June, and 507 kg in October. These values indicate a 33 per-
cent weight loss in animals between fall and winter and spring. Although
sample sizes were not large, and some of the weights obtained during
winter and spring were from "winter..:..killed" moose, it is apparent that
substantial seasonal fluctuations in weight of moose in interior Alaska
normally do occur.
Jordan et al. (1970) concluded that seasonal weight fluctuations
in moose amounted to 6.6 percent for females and 10.3 percent for males.
Ho~ever, Rausch (1959) and LeResche and Davis (1971) reported seasonal
weight fluctuations of 20 percent and '15-30 percent, respectively, for
moose in southcentral Alaska. Verme (1970) found that a "winter...;killed"
bull in Michigan had lost 33 percent of his pre-winter weight.
Energetic demands of lactation resulted in a substantially lower
body weight during the summer than for non-lactating females (Table 6).
Average body weight of four non-lactating females was approximately 12
percent greater than that of lactating females. Each group included
2-year-old animals. Energy requirements for lactation are discussed in
greater detail in a recent publication (Gasaway and Coady, 1973).
Sequential weights of cows at the Kenai Moose Research Center indicated
a weight loss of 8 to 18 percent associated with calving and rearing
young (LeResche and Davis, 1971).
Rapid growth rates and large body size of moose reported in this
study suggest favorable range conditions. Growth of ungulates in both
body mass and skeletal dimensions is closely related to plane of
nutrition (Brandy et al., 1956). Maximum size and growth rates have
been positively correlated with quantitative and qualitative aspects of
the food supply for numerous ungulates, including reindeer (Klein, 1964,
1968), apd black-tailed deer (Odo~oiZeus hemionus coZumbianus) (Cowan and
Wood, 1955). LeResche and Davis (1971) indicated that low growth rates
and small body size of moose on the Kenai' Peninsula may be due to
relatively poor range conditions. Klein (1968) further suggested that
quantitative aspects of the food resource was important in determining
growth rate andbody size. Thus, range "carrying capacity" must consider
winter periods when physiological requirements of animals are low and
food supply is critical, and summer periods when physiological demands
for reproduction, fat deposition, and body growth are high and high
quality food is important.
Klein (1965) has discussed the annual nutritional cycle of deer.
Winter nutritional requirements, though reduced, are generally in excess
of available forage quantity, resulting in a gradual weight loss through-
out the winter. During summer nutritional requirements are relatively
great although high quality forage may be relatively abundant. This
physiological cycle is apparently controlled largely through genetic
mechanisms, since Wood et al. (1962) reported that captive black-tailed
deer fawns stopped growing and adults lost weight during fall and winter,
even though a high quality ration was available throughout the year.
23
Table 6. Weight and total length of lactating and non-lactating cow
moose over 2 years of age during June in interior Alaska (GMU
20A) .
Non-lactating
Weight
Total length
Lactating
Weight
Total length
No.
4
4
No.
4
4
24
Mean
429
264
Mean
379
276
Range
395-463
242-275
Range
367-390
269-284
Large fluctuations in body weight of adult moose reported in this
study may also reflect adequate nutritional status and favorable range
conditions. Nordan et al. (1968) reported that captive black-tailed
deer maintained on a low plane of nutrition exhibited smaLler annual
fluctuations ln body weight than deer fed a high quality ration. The
magnitude of the a.nnual cycle was apparently related to the amount of
fat deposition during summer months which determines the ability of the
animal to effectively .participate in reproductive activities and its
success in surviving the winter.
Reproduction: Thirty female reproductive tracts collected between
February and May 1971 from moose two years old or older were examined.
Twenty-one (70%) of the animals were pregnant. Of 13 females obtained
from the inhabited Fairbanks area, only seven (54%) were pregnant.
Fourteen (82%) of the remaining animals, obtained from the uninhabited
Tanana Flats were pregnant. Three of five (60%) adult females examined
during April 19 73 on the Tanana Flats were pregnant. No yearlings
examined at any time were pregnant.
Ovarian analyses from approximately 70 female moose older than
calves have not been completed at this time.
Pregnancy rates observed in this study during the winter of 1970-
1971 and during April 1973 were somewhat lower than those reported by
other workers. Edwards and Ritcey (1958), Pimlot t (1959), Rausch (1959),
Simkin (1965), Rausch and Bratlie (1965), and Houston (1968) reported
average pregnancy rates of 75, 81, 94, 87, 90, and 90 percent for females
older than yearlings in British Coltnnbia, Newfoundland, Alaska, Ontario,
Alaska, and Wyoming, respectively. Edwards and Ritcey (1958) included
animals collected during October in their calculations, and therefore
may not have detected some pregnancies or pregnancies resulting from
later oestri. Pimlott (1959) reported variation in pregnancy rates of
74 to 87 percent among moose from different areas of Newfoundland. A
similar range of pregnancy rates has been reported by Cheatum and
Severinghaus (1950) for white-tailed deer (OdocoiZeus virginia) in New
York.
Low pregnancy rates observed in this study are difficult to explain.
There is little evidence in the literature for resorption, abortion, or
stillbirth among cervids. Only two out of 283 reproductive tracts
examined by Pimlott (1959) indicated resorption, while Rausch (1959)
found no definite indication of mortality among embryos or fetuses in
Alaskan moose. However, resorption in moose has been recorded by
several workers in the USSR, particularly following severe winters (in
Markgren, 1969). Thus, the possibility of intrauterine death contribut-
ing to the low pregnancy rates in the Fairbanks area must be considered.
Another potential cause of low pregnancy rates may be due to non-
breeding of females. While this has never been implicated as a factor
contributing to low calf production in Alaska, the possibility of females
not being bred under certain situations, either because of low bull:cow
ratios or because of continuous anoestrus during the normal breeding
season, cannot be discounted.
25
Of 22 fetuses examined between February and May 1971, 15 were
female and 7 were male. Sex ratios at birth for most species of mammals
are generally near 1:1, or slightly in favor of males (Robinette et al. ,
1957). However, among some species under favorable environmental condi-
tions, males tend to predominate. Rausch (1959) listed several factors
which may influence sex ratios at birth, including age structure of the
population, reproductive history of the female, nutritional status before
and after birth, and severity of the winter. Generally under adverse
conditions males tend to suffer the greatest intrauterine mortality, and
this factor, considering the severity of the 1970-1971 winter, may have
been responsible for skewed fetal sex ratios observed here (assuming
intrauterine mortality occurs in moose).
On June 27, 1972 a female moose fetus was collected from a 3-year-
old cow on the Tanana Flats (Coady, 1973). Based on fetal growth rates
reported by Rausch (1959), measurements (weight, 6. 71 kg; girth, 42 em;
total length, 70 em) indicated that the fetus was approximately six to
eight weeks from term. Since the gestation period for moose in North
America is about 240-246 days (Peterson, 1955; Rausch, 1959) , conception
of the above fetus may have occurred during December. Normally, the
peak of conception occurs around the first of October for moose in Alaska
(Rausch, 1959).
Markgren (1969) reported that although births during April and early
May are rare in Sweden, calving during midsummer is quite common, and
births during August, September, and even October have been recorded.
Although occasionally reported verbally, the only written account known
to this author of a late pregnancy in North American moose was of a
pregnant cow shot in Alaska on the lower Tanana River in September
(Davis, 1952).
Late pregnancies indicate conceptions decidedly later than during
the main periods of oestrus. Recurrence of oestrus in moose has been
reported by Edwards and Ritcey (1958), Rausch (1959), and Markgren (1969) •
Data presented by Edwards and Ritcey (1958) indicate an interval of
approximately one month between successive oestri. Males are apparently
capable of breeding for a considerable period during the fall since
Rausch (1959) found spermatozoa in the epididymis from mid-August to
December. Thus, the late pregnancy observed in this study suggests
conception during a third or fourth oestrus.
Several factors contributing to conception after an initial oestrus
have been suggested. Russian data (in Markgren, 1969) indicate that the
"heat" during which the cow will allow copulation lasts less than 24
hours, while Altmann (1959) reports for American moose that the bull
stays with a cow for only 7 to 12 days. Therefore, a bull conceivably
may not be available for mating during an initial oestrus. Other
Russian information cited in Markgren (1969) indicates that young
(primarily yearlings) and nutritionally deficient cows may have delayed
oestri.
Although exceptions to and irregularities in most physiological
processes can be found, "normality" of nearly all individuals is the
26
rule. Among moose populations the synchrony and uniformity of oestrus
cycles and subsequent calving among the overwhelming majority of the
population under widely varying environmental conditions remains the
most remarkable phenomenon.
Femur Marrow Fat: Percent fat in femur bone marrow was analyzed
from 65 adult and 61 calf moose examined between February and May 1971
(Fig. 8). A significant difference (P< 0.01) in marrow fat between
adults dying from malnutrition and from unnatural causes (road and rail-
road accidents, shooting, etc.) was found, while a similar comparison
between calves revealed no significant difference (P> 0.50). Duncan's
new multiple range test indicated no significant difference in marrow
fat between moose dying from unnatural causes in remote areas and from
apparent wolf (Canis lupus) predation, and between moose shot in May and
from malnutrition (Fig. 9). Marrow fat of animals dying from apparent
wolf predation, unnatural. causes near Fairbanks, and shooting in May
were intermediate in value and not significantly different. Moose which
appeared to be in the poorest physical condition were selected for
shooting.
Quantative analysis of depot fat has frequently been used as a
criterion of physical condition of animals, and various procedures for
determination of total body fat, subcutaneous fat, abdominal fat,
perinephric fat, and bone marrow fat have been reviewed (Cheatum, 1949;
Riney, 1955; Smith, 1970). Riney (19.55) noted that deposition or
mobilization of fat, in response to favorable or unfavorable. conditions,
occurs first in subcutaneous depots, followed by abdominal, perinephric,
and bone marrow depots. Thus, fat mobilization from bone marrow tissue
probably occurs only after other fat reserves have been largely depleted.
Marrow fat values have been used to evaluate physical condition of
white-tailed deer (Ransom, 1965), elk (Cervus canadensis) (Greer, 1968,
1969), moose (LeResche, 1970), pronghorn (AntiZocapra americana) (Bear,
1971), and caribou (Rangifer tarandus) (Miller, 1972). Greer (1968)
noted that elk in excellent physical condition have marrow fat values of
82 to 99 percent, while marrows from "winter-killed" elk contain less
than 1 percent fat. Mech (1970) found that only 15 percent of wolf-killed
adult moose examined on Isle Royal had low marrow fat content. Relatively
low mean marrow fat content among all groups of adult moose dying from
unnatural as well as natural causes (Fig. 9) reflects the severity of
the 1970-19 71 winter and the poor physical condition of most animals.
However, it is interesting to note that moose dying from unnatural causes
in remote areas had both the highest marrow fat and the highest pregnancy
rate of any group of animals.
While marrow fat from adult moose collected in this study clearly
reflects a difference in nutritional status of the animal, samples from
calves were uniformly low (Fig. 8). Among young animals Abrams (1968)
reported that the sequence of tissue development is nervous system,
skeletal system, musculature, and finally fat. Thus, fat is apparently
a "luxury" which moose calves in interior Alaska, if anywhere, cannot
afford.
27
Fig. 8. Average.percent fat (circles), standard deviation (triangles),
and range (bars) in femur bone marrow of male and female moose
dying from malnutrition and unnatural causes in GMU 20A and
~
0
lL
~
~
~
~
20B between February and May, 1971. Number in circles indicate
sample size.
lOOp· --------------------~
AJu. I u t
80 :·~o--~ r ~
~-
' I
I
i. f
~ 60 lr-[
' -,
·~1 r H ¥J ~
t1.1 ! ~ :J ~
1J f 'l
40 ~j f
>\'-~t H
d ! .,
~ l
I
I
·'·l I
!i !
20
:: ra ·-~-
t: <..:::>
I· ii
i·
i.
ol
I' fl ; I<
I ,,
Calve
I' [I
1: s ,r
I t]
I;
c il 60 .-0
l' +-\\i
'-b +-
::J -:$ c -~ 40 J-0
1 ~ :1 c c :s
20 -~·
0
28
Fig. 9. Average percent fat (circles), standard deviation (triangles), and
range (bars) in femur bone marrow of male and female adult moose dying
from various causes in GMU 20A and 20B between February and May, 1971.
Number in circles indicate sample size. Solid bar indicates no
significant difference between sample means as measured by Duncan's
new multiple range test.
I ~) I
~
I (ltb I
I (oo) I
~ ~~~~~~~~~
0
CX)
0
~
~ 0 .::J o/o
29
0
~ :.,= ·-... ~ s:: -IS
~
~ -tal:
~
VlC ·-
_, ~
~ ~ ~ L C t~~ 'dGJ-0 ~~.t
-.J ::5 C\} LL
~
~
V"\
_"<d
a " s.. '--:1~
~v c-1-= c 0
:5E
QJ ac
_.c
+ di
QJ
Q
~
0
QJ
\1)
':5
<d
v
Winter Mortality of Moose: Due to unusually early and heavy snow
during the winter of 1970-1971, winter mortality throughout a large por-
tion of interior Alaska was relatively high. In addition to deaths
resulting from malnutrition, numerous animals attracted to plowed roads
and railroads were killed by vehicles. MOose deaths resulting from
natural and accidental causes in the Fairbanks area occurred primarily
between December 1970 and May 1971. During this period the Alaska
Department of Fish and Game office in Fairbanks received over 400 reports
of dead, dying, and nuisance moose near Fairbanks. Approximately 250 of
those reports were received during February and March.
Between December 1970 and May 1971, 154 moose dying from natural
and accidental causes were examined. Calves were the most common age
group in the sample. Male and female calves died in approximately equal
numbers, while among adults females tended to predominate (Fig. 10).
The sex ratio of both dead calves and adults may, in part, reflect the
sex ratio in the population of the two age groups. In the Susitna River
Valley in southcentral Alaska, Pitcher (per. comm.) also found that
approximately equal numbers of male and female calves predominated among
winter-killed moose during 1970-71. Amortg adults, however, males died
in higher proportion than they were found in fall sex and age composition
counts.
The relationship between winter weather conditions and winter
mortality was first reported by Severinghaus (1947) for deer, and
recently discussed by Bishop and Rausch (1973) for moose. Severity of
winter snow conditions in the Fairbanks area (Fig. 11) is reflected by
survival of moose calves in the Fairbanks area to 1 year of age (Fig. 12).
Calf survival over the two winters of the most severe snow conditions
(1965-66 and 1970-71) was exceptionally low, while a gradual increase in
the ratio of yearlings per one hundred females occurred following winters
of less severe snow conditions. In Fig. 11, the dotted line indicates
the average chest height of calves, while the solid line indicates the '
average chest height of adult moose.
Moose-Snow Relationships
The following has been taken, in part, from a recent publication by
Coady (1973).
The structural, physical, and mechanical properties of a snow cover
vary greatly, depending on conditions of deposition and subsequent meta-
morphism. Seasonal snow covers behave in an extremely dynamic fashion,
and the only completely predictable phenomenon is change itself. Meta-
morphic processes which take place within a seasonal snow pack have been
described by numerous workers (Bader et al., 1939; Formozov, 1946; Gold,
1958; Kingery, 1960; Benson, 1967, 1969; Trabant, 1970). While wind
action is a major factor affecting snow as it precipitates (Sommerfeld,
1969), diagenetic processes resulting from temperature, time, and
settling (Keeler, 1969) begin immediately after deposition. All features
of a snow pack reflect post-depositional changes as much or more than
they reflect the character of snow at the time of deposition. High
temperature relative to the melting point of snow and steep temperature
30
~
MALNUTRITION UNNATURAL DEATHS ....
0'1
28 1-'
0 .
24 !loll> ~0'1
20 Males Males li (D .... t:l Ill OQ'd
(D
16 ( n ........
t:l H>
(/) rtl-'-
12 !D n
1'1 -v Ill 0 (D
1-':< E 8 \0
"'-11'1
011>
I rt c 4 '-I t-'•
1-'0 . <! 0
0 H> ., s ~
0 '+-0 0 4 Ill
(D
?I" ~ 8 t-'•
1-' <l) 1-'
CD ...0 p.
E 12 t-'•
t:l
:::::J 16 Females Females ~ z
N 20 0 >
24 ~
I I I I I I I I I I I I I p. I I I I I I I I I I I I I I I I I I I I I I I I N
28 0 <I 2 4 6 8 10 12 14 16 18 <I 2 4 6 8 10 12 14 16 18 ? t:1:l
Fig. 11. Relative yearly snow severity near Fairbanks, Alaska, calculated by plotting
snow depth on ground on the last day of the month, between October and April,
and determining the relative area under the curve with a planimeter. Data
are taken·from National Weather Service Records from Fairbanks .
. ,-.: ..
• ; RtLflrwl! · SnoUJ
StvUtTY·······IlS . ..; . -··-·-··· :ual. ._. . l'f( lfl bl. '\l.
It>() f----+-~--:--:-----A duff Chest
C hes+
Hei.9J,.,t_
l-le·tc.; ht----Cal-f
3 So.
0
<:
lf1
.r\ \ I I oL---+---~~----~----+4~---r~----+l~(-----r\
1'1'1'1-SO, I'ISI-SJ.
lbO \31
10
----·--,·,---.-
'.
-----r ·,~·------
!
' !
"'b
"'S
S..l.
1'\0
.1')5" l\0
C: \---' . r
1\0 .10
HoO
/ \ I \;\
. ' \ /'<....... i ·~ j \ , "\\ dl ,~ r/ , -~ --+-+----+.----+----·-·
I CJ 71-?:l. /9?).-?3
'l')
·~s4 -ss
Fig. 12. Survival of moose to one year of age as indicated by spring sex and age composition
counts in GMU 20A. Data are taken in part from Rausch (1971).
50 -
45 -
40 -
Cf.l 35 -~
(..)
0 30 -0
r-i ..
Cf.l
c.!> 25 -z
1-1
~ 20 -~
>-<
15 -
10 -
5 -
1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973
YEAR
.,
gradients are effective in promoting vapor transport, a major cause of
metamorphism. Constant fluctuations in air temperature and accumulation
rate of snow cause continual changes in both thennal and gravitational
forces which are perceptible within days or even hours.
The properties of snow can be divided into fundamental and derived
characteristics. A discussion of tundamentai properties, which include
size, shape, orientation, and packing of particles, is beyond the scope
of this review. While fundamental properties of a snow cover do bear a
relationship to.the mechanical properties and are important for a com-
plete understanding of snow metamorphism, they are probably of minor
significance in ungulate snow ecology (Pruitt, 197la).
Derived properties of snow are those which depend on fundamental
properties for their magnitude and rate of change (Keeler, 1969) •.
Generally, they are more easily measured than fundamental properties,
and are useful indices to the nature of snow. Although derived properties
are numerous and diverse, relatively few are generally measured to
characterize a snow cover. The most commonly measured derived properties
used in biological work are depth, temperature; density, and hardness.
Physical characteristics of moose affecting their mobility in snow
have been related to height of the animal and weight-load-on-track of
the feet. When moose sink into snow to depths approaching chest heigh.t
and are forced to "plow" or bound through the snow, energy required for
movement is greatly increased. However, snow depths below chest height
may hinder movement by increasing resistance to movement of che legs.
Weight-load-on-track is a measure of the weight per unit area on the
feet, and reflects the extent to which a moose may be supported by a
s·ubs trate. Under situations in which snow will partially or fully. support
a moose, resistance to and energy required for movement may be reduced.
Procedures for measuring chest heights and track loads have recently
been described in detail. Kelsall (1969) measured chest heights from
the tip of the thoracic limb, with leg extended perpendicular to the
body, diagonally to the sternum. The measurement may slightly over-
estimate actual chest height since the leg may be less extended on a
standing than on a decumbent animal. In many studies hoof load, or
weight on hooves alone, has been used co measure the bearing surface of
the legs. However, Kelsall and Telfer (1971) and. Telfer and Kelsall
(19 71) indicated that the entire foot from the tip of the hoof to the
dew claws supports an ungulate in soft snow, and described a procedure
for measuring foot areas and calculating foot loads. Foot loads measured
by the previous technique are probably minimal since the measurement
does not allow for spreading of hooves and angular placement of legs in
snow. However, the actual foot load is probably somewhat greater since
only when standing is weight supported on only twci feet. In addition,
Kelsall (1969) thought that as much as three-fifths of the weight· of a
standing ungulate is distributed on .its forefeet.
The significance of chest heights and track loads of moose reflect-
ing adaptation to snow was first shown by studies in Russia and later in
North America. Nasimovich · (1955) reported that chesc heights of adults
34
averaged 105 em or greater. Kelsall (1969) found that average chest
heights of male moose in Eastern Canada increased from 81.9 em for
calves, to 98.9 em for yearlings, and 104.7 em for ariimals older than
four years. Kelsall and Telfer (1971) found an average chest height of
106 em for male moose older than four years in Western Canada. Similar
chest heights of 84, 96, and 104 em for 60 calves, yearlings; and moose
older than two years, respectively, have been found in interior Alaska.
Nasimovich (1955) noted that moose on the Kola Peninsula in Russia
were unaffected by snow depths of 40 to 50 em, while movement was
definitely impeded by depths of 60-70 em. At 60-70 em calves frequently
followed in the trail of adults. Nasimovich (1955) concluded from the
Russian.literature that snow depths of 90 to 100 em may be considered
critical to moose, since at that depth winter mortality substantially
increased. Kelsall (1969) reported similar observations from. Eastern
Canada, noting .that movement was unrestricted by depths of 44 err and
severely restricted by depths of 70-99 em. Snow depths greater tha:n
90-100 em were critical for moose unless of very short duration. Ritcey
(1967) and Prescott (1968, in Telfer 1970) found that depths of 60-70
em restricted mobility of moose in British Columbia and Nova Scotia,
respectively. In Alaska substantial winter mortality has occurred in
several areas of the state when snow depths exceeded 90 em for several
months.
The above data suggest that snow depths up to 40 em, or depths
approximately equal to the carpus or tarsus height, cause little or no
hindrance to movement. From 40 to 60-70 em, or depths approaching two-
thirds of the chest height, movement is only slightly rest: ric ted. At
depths greater than 70 em movement is definitely impeded, while at depths
greater than 90 em, or approximately equal to or slightly less than chest
height of standing moose, movement is greatly restricted to the extent
that adequate food intake may become impossible. Calves, because of
their shorter legs, may be restricted by snow depths somewhat less than
those affecting adults, while large males may be·least affected by deep
snow. Differential movement of sex and age groups during winter reported
by several workers (LeResche, 1973; Pulliainen, 1973) may reflect, in
part, the relative ability of the different groups to move in deep snovJ.
Heights of moose from interior Alaska and the Kenai Peninsula have
been compared to illustrate that leg length in moose may be adaptive to
snow conditions. In interior Alaska in winter moose habitat snow depths
of 70 em or more, that persist for several months are the rule, and
depths in excess of 90 em are not unusual. On the Kenai Peninsula,
however, depths in winter moose habitat range near 40 em for short:
periods, and seldom reach 60 em. Since chest heights of moose from the
Kenai Peninsula were not available, a ratio of shoulder height to total
length was used to reflect relative differences in leg length and
presumably in chest height. of moose from the two areas.. Average ratio
for 31 fully grown moose from the Inte;rior was ~68, while that of 64
similar animals from the Kenai Peninsula was .59. Simi~ar ratio for 18
calves 6 to 12 months of age from the Interior, and 50 calves from the
Kenai Peninsula were . 72 and . 70, respectively. Average shoulder heights
of moose from the Interior and from the Kenai Peninsula were 182 em and
35
172 em for adults, and 148 em and 141 em for calves, respectively.
both relative and absolute height of moose is lower, particularly
adults, from the Kenai Peninsula than from interior Alaska.
Thus,
among
Variations in body size of animals may be due to genetic or nutri-'
tional differences. Since data from the Kenai Peninsula were obtained
from moose on relatively poor range (LeResche and Davis, 1971), and data
from the Interior were from moose on relatively good range (Coady, 1973),
differences in skeletal dimensions, of animals from the two areas may
reflect nutritional differences. While nutritionally related differences
in skeletal growth do occur (c.f. Klein, 1964), there is little reason
to expect that poor range on the Kenai Peninsula is responsible for
preferential growth of body length over foreleg length. Thus, while
nutritional deficiencies may account for smaller absolute shoulder height
of Kenai Peninsula moose, it is probably not responsible for reduced
height of animals relative to length.
\fuile long legs per se are not necessarily an adaptation to deep
snow (e. g., height facilitates the browsing habit), the selective
advantage to moose of increased leg length in regions of deep snow is
obvious. Therefore, observed differences in relative height of moose
between the Kenai Peninsula and the Interior in Alaska are probably of
genetic origin and may be related to differences in snmv conditions
between the two areas. Nasimovich (1955) noted that reindeer-from the
taiga zone where deep, soft snow is common have longer legs than those
animals from tundra areas. Nevertheless, additional studies would be
useful.
Nasimovich (1955) reported that the average track load of "several
moose" in Russia was 420 g/cm2 .. This value presumably represents the
total foot load, and not just hoof load, of the animal. Kelsall and
Telfer (1971) measured average foot loads of approximately 710 g/cm2 for
male moose four years and older during December in Western Canada.
Higher average hoof loads of 789 to 922 g/cm2 were found by Kelsall
(1969) for similar aged male moose from two areas of Eastern Canada.
However, the higher values were measured prior to rut, while the_ lower
hoof loads were obtained following the rut and presumably after consider-
able weight loss.
Foot loads of moose in interior Alaska are not uniform btit vary
with age of animal and with season. Average foot load decreased from
593 g/cm2 for eight adult cows in October to 432 g/cm2 for 19 adult cows
between April and June. Thus, as winter progresses and snow depth and
hardness . increase, foot loads of adults decrease due to seasonal loss of
body weight. Foot loads of nine calves between April and June averaged
317 g/cm2 , over 100 g/cm2 less than adults during the same season. Thus,
the shorter legs of calves may in part be compensated for by lower foot
loads. No seasonal increase in hoof size was noted for Alaskan moose,
as Pruitt (1959) reported for caribou.
· Snow density has been related to track depth of moose. Kelsall and
Prescott (1971) concluded from their extensive observations that snmv-
densities of 0.10 to 0.19 g/cm3 do not support moose, densities of 0.20
36
to 0.29 g/cm3 provide some support, and densities of 0.30 to 0.39 g/cm3
limit foot penetration to approximately 50 percent of the snm..r depth.
Nasimovich (1955) reported that snow densities of 0.20 to 0.22 g/cm3
provide little support to a running moose, while densities of 0.24 to
0.26 g/cm3 limit foot penetration to two-thirds of the total snow depth.
However, under these conditions, moose experience difficulty lifting
legs from holes in the snow.
Kelsall (1969) and Kelsall and Prescott (1971) were unsatisfied
wi.th attempts to relate ungulate support to snow hardness. Theoretically,
a standing moose should 9e support~d by a vertical snow hardness equal
to or greater than its track load (Kelsall, 196 9; Kelsall and Prescott,
1971). However, Kelsall and Prescott (1971) found the support capacity
of snow to be extremely variable, depending on the presence or absence
of surface crusts and the hardness of underlying snow layers. Both
white-tailed deer and moose frequently broke through crusts that should
easily have supported the animal. Moose, with maximum track loads of
1,000 g/cm2 , broke through crusts of 8,000 g/cm2 at the surface, 10,000
g/cm2 at 15 em, and 90,000 g/cm2 at 34 em. Moose also broke through
crusts of 20,000, 10,000, 30,000, 40,000 and 25,000 g/cm2 to ground
level at a depth of 73 em. On other o~casions moose were supported by
surface crusts of 2,000 to 30,000 g/cm . Peek (197la) noted that surface
crusts of 7,500 g/cm2 supported moose in Minnesota. In interior Alaska
extremely hard crusts are unusual, although an adult moose walking on a
trail penetrated 20 em in 30 em deep snow when the hardness was 2,000 to
4,000 .g/ cm2. On another occasion both a cow and calf walking on a trail
penetrated 39 em in 90 em deep snow when the hardness was 1,000-2,000
g/cm2 .
Preliminary attempts to use the Rammsonde penetrometer to quantify
the support capacity of snow for moose have been attempted. The inte-
grated ram hardness (Ri) was calculated for the total ram hardness of
the snow to foot penetration depth (Table 1). Average Ri ranged from
188 to 570 kg/em for penetration depths of 22 and 42 em, respectively.
Although noi: immediately evident from the limited data above, further
study may reveal a predictable relationship between Ri and depth of foot
penetration in or resistance to movement through snow.
Throughout most of the circumboreal range of moose and within favor-
able habitat, snow conditions that significantly benefit moose by provid-
ing support apparently are seldom extensive or persistent. Even on the
tundra of Alaska where snow density and hardness are very great, the
snow cover in winter riparian habitat provides little or no support to
moose. In other areas supporting crusts are usually extremely localized,
and are apparently rarely consistent enough to facilitate travel. Murie
(1944), Nasimovich (1955), Kelsall and Prescott (1971), Peek (1971a),
and others indicated that snow conditions which only partially support
moose may make movement more difficult and hazardous because of the
resistance to movement of legs provided by the dense snow and/or the
danger of abrasion from hard crusts. Snow conditions in which depth of
penetration is variable may require an animal to expend more energy
recovering from breaking through crusts and climbing onto crust·s than
would be required to move through deep snow offering no support. However,
37
dense, hard snow offering uniform support, such as ski or snow machine
trails, may be extensively used.
Comparison of foot loads of moose from different regions may indi-
cate adaptation to varying snow conditions. Iri Western Canada Kelsall
and Tel fer (19 71) measured average foot loads of 710 g/ cm2 for adult
moose durin2 December, whereas in interior Alaska I report foot loads
of 593 g/cm for adults during October. Normal snow conditions at the
collection site in Western Canada were not given, but presumably snow
depth and hardness were at least as great as those in interior Alaska.
Although I followed procedures described by Kelsall and Telfer, p0ssible
differences in measuring foot area must be considered.
The influence of snow on seasonal movements of moose has been
reported by several workers, although quantitative observations are
relatively limited. The greatest effort to document and review relation-
ships between snow and moose migrations has occurred in the USSR (Formozov,
1946; Nasimovich, 1955; Knorre, 1959, 1961; Egorov, 1965; Heptner and
Nasimovich, 1967 in Van Ballenberghe and Peek, 1971). However, signifi-
cant contributions have also been made in Europe (c.f. Pulliainen, 1973)
and in North America (Edwards and Rit cey, 1956; Ritcey, 196 7; Knowlton,
1960; Houston, 1968; Kelsall and Prescott, 197~).
Nasimovich (1955) drew several conclusions from the copious Russian
literature regarding the influence of snow on moose migrations in both
mountains and flatlands of the USSR. , Basically, in regions where maximum
snow depth averages less than 50 em and deep snov1s are of short duration,
extensive seasonal migrations are uncommon, although local movements may
occur. However, in areas where maximum snow depths in excess of 70 em
persist for long periods, seasonal movements occur from areas of deep to
less deep snow. The longest migrations, ranging from 150 to 300 km,
occur among animals living on flat terrain, although migrations of 100
to 150 km are common across divides or to lower elevations in mountainous
regions. Gradual movements generally occur between October and January,
and may coincide either with the first lasting snow cover or with snow
depths of 25 to 45 em. However, some animals migrate before snowfall
while others remain in summer habitat until snow depths reach 60 to 70
em.
Pulliainen (1973) reviewed the literature describing relationships
between snow.and moose migrations in Scandinavia. Movements in most
areas are closely correlated with prevailing snow conditions. Gradual
movements from high to low elevations usually begin in November or
December, although they may be 'de1ayed or may not occur during years of
little snow. Some animals, particularly cows with calves, begin migrat-
ing at first snowfall, while others, particularly bulls and cows without
calves, remain at high elevations until snow depths reach 60 to 70 em.
However, formation of icy crusts may initiate downward migration of
almost all animals (Krafft, 1964). Return to summer rarige is usually
abrupt, and occurs during May after snow melt has exposed patches of
ground.
In North America several early workers, including Murie (1934) on
38
Isle Royal, Hosley (1949) in Maine, Bauman (1941, in Hosley) in
Yellowstone Park, Murie (1944) in Alaska, and Hatter (1946, in Hosley)
have copl!llented on snow depths and moose movements. However, Edwards and
Ritcey (1956) in British Columbia were the first to present detailed
observationson the relationships between moose migrations and snow
conditions. They found that a gradual altitudinal movement from 1525-
2135 m to 760-1220 m during fall and winter coincided with a gradual
increase in snow depths on summer range. A rapid return to higher
elevations during spring coincided with a rapid snow melt. Segregation
of winter.and summer ranges was not complete, although most animals had
departed higher elevations by the time snow depths J;eached 75 em. Upward
movement to summer range was initiated when melting had reduced snow
depths t:o 30 to 45 em. cold t~mperatures appeared to moderate the effect
of snow by speeding movement downward in the fall and retarding movement
upward in the spring.
Ritcey (1967), also in British Columbia, noted that deep snows .at
high elevations were responsible for the fall and winter movement to
elevations below 1050 m. Arrival on winter range generally began in
November when snow depths were less than 15 em, and continued throughout
the winter. Departure from winter range began in late February or March,
while snow depths were as great as 125 em but declining.
Kelsall and Prescott (1971) and Telfer (1967a, b) in the Canadian
Maritime Provinces, studied winter segregation of white-tailed deer and
moose in relation to moose sickness induced by Pa:rela:phostrongylus
tenuis. Although segregation was not complete, deer generally wintered
at elevations below 200 m, while moose remained at elevations above 200
m. Snow depths of 85-90 -em above 200 m did not initiate downward migra-
tion of moose, even though snow depths were more favorable and browse
more abundant at lower elevations. However, relatively high density and
hard crusts due to winter thaws and rains may provide some support to
moose, thereby reducing the effective snow depth (Telfer, per. comm.).
In Montana Knowlton (1960) and Stevens (1970) reported that deep
snows in summer range above 1830-2135 m initiated movements to lower
elevations. Movements were gradual, and frequently lasted from December
to Harch. Harry (1957) in Wyoming reported that increasing snow depths
at high elevations resulted in a gradual downward movement and concentra-
tion of moose in mountain valleys by December. Snow condit:Lons associated
with these studies in Montana and Wyoming were not reported. However,
Houston (1968) in Jackson Hole, Wyoming, found that downward movements
from 2190 m to winter range at lower elevations began in late December
in response to snow depths of about 80 em on the summer range. Movement
to spring and summer range began in late March in response to a snow
crust formation capable of supporting mooose ~d in response to disappear-
ance of snow from south and east slopes. Moose densities on winter range
were 10 moose/km2 in Mont~na (Stevens, 1967:7 1 in Stevens, 1970) and 19
moose/km2 in Jackson Hole (Houston, 1968). 1
•
Seasonal movements
noted by some workers.
1956 at high elevations
of moose in response ~;o snow in Alaska have been
Rausch (1958) reported\ that an early snowfall in
in southcentral Alaskal caused an early migration
39
in November to lowland areas. Rausch concluded from his extensive
observations that snow influences but does not cause seasonal movements
of moose.
Fall migrations in hills and·mountains of interior Alaska generally
occur as a gradual downward movement between December and February or
March. The extent, time, and composition of the migrating animals appear
to be closely related to snow conditions. In late November and early
December, 1970, snow depths of 90 em (55 em above average) at elevations
of 600 to 915 m in hills near Fairbanks apparently caused an abrupt down-
ward migration of moose to elevations below 300 m. Over 1200 animals
were seen on or moving toward low elevation riparian habitat during 23
hours of Alaska Department of Fish and Game aerial surveys in early
December. Almost no animals were found on the usual upland fall and
early winter range. Snow depths of 110 to 120 em persisted until early
April and moose remained along rivers until mid~March when they apparently
dispersed into adjacent timbered areas. Similar observations during
1970 were reported by Bishop (1971) for western interior Alaska, where
snow depths of 60 em during the end of November apparently precipitated
an early movement of moose from upland areas to lower elevation riparian
habitat, where they remained until late March.
The response of moose to winter weather factors has been studied in
interior Alaska since 1971. For example, relationships between moose
movement and snow conditions during 1971-1972 were examined on a study
area near Fairbanks (Fig. 13). "Tracks-Valley" indicates the seven-day
total of fresh moose tracks crossing a one-half mile long transect in a
valley. The valley is located at 245 m elevation, and represents typical
winter riparian moose habitat. "Moose-Hills" indicates the number of
moose counted during frequent intensive aerial surveys in a 75 krn 2
drainage above the valley transect. The upland site ranges from 550 to
670 m elevation, and consists of mixed conifer and deciduous trees and
shrubs which characteristically support modest numbers of moose during
Stmlrner and fall in interior Alaska. While neither "Track-Valley" nor
"Moose-Hills" indicates actual number of animals, they are thought to
reflect the trend of animal abundance on each site. Snow depths and
integrated Rannnsonde resistance of the total snow cover (Ri) in shrub
communities on the two sites are also noted.
A decrease in moose observed at high elevations and an increase in
fresh tracks at low elevations occurred during late December and early
January. The decrease in fresh tracks in the valley during mid-January
may have been related to reduced activity during extremely cold tempera-
tures (-40° to -50°C) during that period, while the decrease in tracks
after late February may have resulted from a dispersal of animals away
from the riparian habitat where the transect was located. After January
the number of moose in the hills remained low throughout the winter.
Snow depths at high elevations gradually increased to about 80 ern
at the time of movement in late December. While lowland snow depths
throughout January and early February ranged from 15 to 25 em below
those in the hills, depths at the two sites remained nearly identical
during the rest of winter. The R. of the snow cover sharply increased
1
40
Fig. 13. Relationship between moose movement between and snow depth and
Rammsonde hardness at high and low elevations in the Chatanika River
drainage (GMU 20B) during winter 1971-72. See text for explanation
of figures.
0 9
I
I
~-,..-r -~
I : I: I ·\ ~ J4 ~
I ),? I J, <
? I I >. I >. <l> I W(f) I -(f)
--I -I - -· o
I >o ·-I > J: (._"( ~ C~ I :r: I l \ <"
I
0 0 i . 0 0 .. .-:''
('··<> '·.' ~
0 4 J ', ' /.,)
\ ~ I
\ ~ ~-' -."-.......... -,......, ..._ ' ·',) ~ '""-' .,,J \ ;. I J ---~
0 -.... I I \ ....._
I 1 ! I 0
' I I I . -I ,
I ) I .Q
t) 6 :q __ /·
I : \ }., / l -:~ : -'' "\ (------<
G (. ', \ ~ -J " ', \ "' 0\'' \ ' ( 9 \
n ? <} . -
l, : \q l \ -J ~j ~
0 0 \ I I
\
I \
. I ).,
I I y
~ •6 () <> -~)0 { 1> \ 0 b . z
I 1-L__ ,
0 0 0 0 0 0, oo 0 0 0 0
0 L() 0 l{) 0 l[):. (\j
(\J ---( w~. 0 ~) .'C:J (W:J} l/ldtJO /110U$ S//,IH-CJSOO}Y /.:Jjj0/1-s.y:JD.I.J.
41
during December preceding movement of animals. The increase resulted
from both an increase in total snow depth and an increase in ram hardness
of given depth increments. The dispersal of moose from lowland riparian
habitat to adjacent areas during March may have been influenced by the
declining Ri making travel less difficult. Dispersal from riparian
habitat in March may also have been related to the lower snow depth,
density and hardness in deciduous and conifer tree communities during
that time. The range for snow density of settled snow at the upland
shrub site increased from 0.16 -0.24 g/cm3 in late November to 0.20 -
0.31 g/cm3 in late December, while the range of.snowhardness for settled
snow increased from 10-50 g/ cm2 to 50 -500 g/ cm2 during the same period.
Conclusions regarding the significance between integrated Rammsonde
resistance and movement of moose would be highly premature at this time.
However, based upon the above data and upon similar correlations between
Ri and moose behavior in other study areas during both 1971-1972 and 1972-
1973, further studies using the Rammsonde penetrometer appear justified.
Movement of moose onto non-riparian lowland habitat during 1971-
1972 corresponded closely with that onto riparian areas (Fig. 14). Sites
1 and 2, located 90 km from the above study area, are each approximately
1. 5 kni2 in size. Land clearing 10 to 15 years ago has resulted in a
dense regrowth of shrubs and low trees. Moose movement onto both sites
1 and 2 began in late December, while by early March nearly all animals
had dispersed from the sites, apparently into more densely vegetated
areas. Snow depths on the sites averaged about 70 em in late December
when animals began to appear, and remained near 80 to 90 em until late
April. The maximum number of animals was 11 (density 7/km2 ) on site 1
in mid-January. During the preceding winter snow depths on the sites
averaged 115 em in January and the maximum number of animals during. that
time was 36 (density 24/km2).
Seasonal migrations of moose in interior Alaska are not always
influenced by snow conditions. Movement of some animals from lowland
summer range to either upland or riparian shrub habitat may begin in
August, well before snowfall occurs, and continue throughout the winter.
However, while initial movements may be related to factors other than
snow, the speed and extent. of migration are apparently influenced by
snow. During winters of early or deep -snow, movement of most animals
from lowland summer ranges may occur sooner and to a greater extent than
during winters of late or little snow. Availability of browse as affected
by snow depth may be particularly important in influencing movements over
flat terrain where local differences in snow conditions are not great.
For example, late snowfall may have accounted for exceptionally heavy
and extensive use of some low (40 to 60 em high) willow (Salix puZchra)
communities on the Tanana Flats near Fairbanks during fall and early
winter, 1972.
Movement to summer range in interior Alaska apparently occurs dur-
ing a relatively short period after snow melt has exposed patches of
bare ground. Observations of animals and tracks suggest that when snow
cover persists into mid-to late May, substantial movement of animals
does not occur until that time. However, an early thaw results in an
42
Q)
(j)
0
0
00::::::::: c::;:_
~
C)
.D c c..
-
--0..
()
0
5
0 c
(/)
Fig. 14. Movement of moose and snow depth at two small lowland wintering. sites
near Fairbanks, Alaska (GMU 20B), during winter 1971-1972. Number of
moose were determined by aerial count.
1·0
IO
,-./ ,-.}--o---'-...) I //~
50i-;O-d
10-~ .
Site 1
Site 2
~ /....,.------o--~
\
'o
O l---~--~---~~--~~----~--~-. I I
~OV 1 DEC 1 JAN 1 FEB 1 MAR 1 APR 1 MAR 1
Month
43
early movement to summer range during late April and early May. Advanced
snow melt during spring 1973 resulted in a 70 kin migration between
April 10 and April 20 of a radio-collared moose from winter to summer
range.
Although the above data are preliminary and highly limited in scope,
they illustrate an approach to studying moose-snow relationships which
may prove useful in other areas. Detailed observations of moose distri-
bution and movements, snow parameters, and temperature and wind conditions
in several areas of interior Alaska over three years wili be reported in
a future publication.
Habitat selection and movement on winter range in relation to snow
conditions have been reported in several excellent studies (Nasimovich,
1955; Des Meules, 1964; Telfer, 1970; Berg, 1971; Peek, 197la, b; Van
Ballenberghe and Peek, 1971), and will therefore not be further con-
sidered here. However, most studies suggest an increased use of dense
covE7r with an increase in snow depth, density, and/or hardness, and a
relatively small winter home range, although actual snow conditions
causing a change in habitat selection or home range size are variable.
Since February 1971, 195 moose observations, 34 aerial moose surveys,
and 56 weekly track counts have been completed in the Fairbanks area.
Data analyses are incomplete, and will be presented in a future report.
All records are on file in the Alaska Department of Fish and Game office,
Fairbanks.
Radio Telemetry
The six radio transmitters were tested on horses at Fairbanks for
one day and at Kenai on Moose Research Center penned moose for two days.
All transmitters and collars functioned satisfactorily during testing.
The operational life of the radio collars was as follows: one unit,
seven weeks; one unit, eleven weeks; two units, seven months; two units,
seven months plus (still operating). However, the signal of one .currently
operating transmitter was not received for seven months after it was
placed on the moose. On June 18, 1973 the signal was received in the
area where the moose was instrumented. It is not known whether movement
of the moose out of the search area and beyond the range of the receiver
or or intermittent operation of the transmitter was responsible for not
receiving the signal.
During the operation of the transmitters, the moose were located a
total of 158 times between November 21, 1972 and June 18, 1973. Three
of the radio-collared moose remained in the Elliott Creek burn until
late December, when they migrated out of the burn within 10 days of each
other. One of the animals moved into a mature deciduous tree stand
(elevation 600m), midway between the burn and the Chena River), and
remained in that area until late April. During a period of ten days the
moose then moved 55 km to a black spruce (Picea mariana)-bog habitat in
the Tanana Flats (elevation 130m). The other two moose moved 30 to 40
km directly from the burn to shrub communities along the Chena River and
44
the Chena Hot Springs Road (elevation 170 rn) where they remained until
late April. One of the animals then occupied adjacent black spruce~
deciduous tree-bog habitat. The transmitter failed on the second moose.
A fourth moose remained in the burn· until early April, when she moved
directly into.black spruce-bog habitat along the Chena River.
Mopthly aerial surveys in the 90 krn 2 Elliott Creek burn also indi-
cated a gradual movement of moose out of the area.
Between the end of November and the end of December, snow depths in
the burn increased from approximately 30 to 55 ern. Movement of radio-
collared moose out of the burn during late December may have been
influenced by rapid accumulation of snow during that time. Snow depths
in the burn between mid-January and mid-March ranged between 50 and 60
ern. Therefore, the sharp decline in total number of moose in the burn
between January and March was apparently not in response to increasing
snow depths, but was influenced by other factors. Movement of radio-
collared moose into black spruce-bog habitat during late April corre-
sponded with the appearance of patches of bare ground at that time.
Between November and mid-April, while the ground was 100 percent
snow covered, 93 percent of the collared moose located electronically
were then.visually spotted. However, after mid-April, with the appear-
ance of bare ground, only 58 percent of the collared moose located
electronically were visually sighted. The decrease in visibility was
probably due to a number of factors, such as greater difficulty sighting
moose on snow-free ground, change in habitat selection to more dense
cover, and a more secretive nature with the approach of parturition.
Analysis of moose telemetry data is incomplete, and will be pre-
sented in a future publication. However, the use of radio telemetry in
combination with other methods of monitoring seasonal movement patterns
and habitat selection in response to various factors appears justified.
However, a larger number of transmitters (20 to 25) of longer operational
life (one or more years) would be of value.
ACKNOWLEDGMENTS
The ADF&G laboratory staff, especially David Harkness and EdWard
Kootuk, along with ADF&G technician Mike Vierthaler, collected and
obtained weights and measurements on many moose . Mike Vierthaler ably
made detailed snow measurements on numerous occasions. H. Don Draper,
resident of 40 mile Steese Highway and sourdough extraordinaire, ·pro-
vided extensive moose observations and daily counts of moose tracks
during two winters. ADF&G biologists Richard Bishop and Robert LeResche
offered valuable suggestions and ne·eded assistance in radio-collaring
moose. ADF&G biologist Tony Smith located radio~collared moose when the
author was unavailable, and flew monthly aerial surveys during winter
1972-73 in the Elliott Creek burn. Among pilots, William Lentsch stands
out for his ability, persistence, and interest in locating radio-collared
moose. The assistance of the above individuals and numerous others is
greatly appreciated. A special acknowledgment is· extended to John J. Burns,
45
ADF&G biologist, fat,;. timely advice and. guidance in defining res·earch ·
needs and designing many aspects of this and other studies during their
initial stages~ <ti
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·, __
53
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PREPARED BY:
John W. Coady
Game Biologist
SUBMITTED BY:
Richard H. Bishop
Regional· Research Coordinator
54
APPROVED BY :
ARLIS
Alaska Resources
Library & Information Service:
Ailchc~2:!e. 1-Jask;:J