599.65

F2MDS

1979

jME documents COatCTlON

OCT 1 6

WNTW STHE IMAM

^ 930 E Lyndale ^ve

Helena, Montana 59601

III

Montana

Deer

StudiGS

Montana Dept, of Fish, Wildlife & Parks
Federal Aid Project W-120-R
Progress Report for Period
July 1, 1978 - June 30, 1979

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JOB PROGRESS REPORT

RESEARCH PROJECT SEGMENT

State of Montana

Statewide Wildlife Research
Statewide Deer Research

Job Nos. 1, 2, 3, 4

Project W-120-R-10
Study No, BG-l.OO

Name

Title

Period Covered: July 1, 1978 - June 30, 1979

Prepared by: Richard J. Mackie Approved by: John P. Welgand

Kenneth L. Hamlin Eugene 0. Allen

Henry E. Jorgensen

John G. Mundlnger

David F. Pac

Date: September 25, 1979

Since this is a Progress Report only, results presented herein are not
necessarily final and may be subject to change. For this reason, the
information contained in this report may not be published or used for
other purposes without permission of the Director.

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TABLE OF CONTENTS

Page

INTRODUCTION 1

Northwestern Montana

Swan Valley whitetail study 5

(Study BG-1.00, Job 1)

Salmon Lake whitetail study gy

(Study BG-1.00, Job 1-Supplement)

Southwestern Montana

Mule deer population study 69

(Study BG-1.00, Job 2)

Mule deer habitat selection study i T c

(Study BG-1.00, Job 2-Supplement)

Schafer Creek mule deer study i2x

(Study BG-1.00, Job 2-Supplement)

Brackett Creek mule deer study (1st study) i2A

(Study BG-1.00, Job 2-Supplement)

Brackett Creek mule deer study (2nd study) 12S

(Study BG-1.00, Job 2-Supplement''

Eastern Montana Breaks and Riverbottoms

Mule deer population study 129

(Study BG-1.00, Job 3)

White-tailed deer population study 167

(Study BG-1.00, Job 3)

Eastern Montana Prairie - Agricultural

Mule and white-tailed deer population studies 175

(Study BG-1.00, Job 4)

INTRODUCTION

In 1975 a statewide deer research program was initiated in Montana.

Broadly, the objectives of this program were to:

1. Provide a more detailed understanding of the population
biology and habitat relationships of deer and of the
factors limiting deer numbers in the diverse environments
in which deer occur in Montana;

2. Develop new or improved methods for measuring deer popula-
tion and habitat parameters, new guidelines for applying

information and technology more effectively,
and/or new criteria for interpreting field data in terms
of management needs; and

3. Establish new guidelines for consideration of the habitat
requirements and relationships of deer in other game,
range, forest, and land management programs and practices
in Montana.

The study entails concurrent, comparative investigations on the population
ecology and habitat relationships of both mule deer and white-tailed deer
in all of the major ecological or broad habitat types on which the two
species occur. It includes both descriptive and evaluative research. The
former is required to provide essential baseline information concerning
deer behavior, habitat requirements and relationships, to clarify exist-
ing knowledge, and to develop hypotheses concerning the environmental
requirements and relations of deer. The study also involves efforts to
promote, assist in, and generally coordinate more extensive and pilot
deer management studies across the State, and to draw together and relate
findings of these studies to those of more intensive investigations and
to the overall study objectives.

Current deer studies are located on the accompanying map of Montana
(Fig. A). Solid circles denote deer research study areas from which find-
ings are included in this report. Open circles denote management and other
special study locations. Those inscribed with a T are management studies
involving only deer population trend and classification measurements to
date, though more intensive effort may be planned. Completely open
<^T^cles denote studies which may also Involve tagging and marking, or
monitoring radio-collared deer, food and range use habits, and/or other
habitat relations. Circles inscribed with an X denote special studies
conducted by the Ecological Services Division of the Fish and Game Depart-
ment and other agencies. The latter include the Decker Deer Study con-
ducted by the U. S. Fish and Wildlife Service and deer studies in Glacier
National Park.

Findings from management surveys and investigations are reported independ-
ently in Montana Department of Fish and Game Regional Progress Reports under
project W-130-R and as other special progress reports from the Ecological
Services Division or the Agency concerned.

-2-

This report compiles individual study and job progress reports for investi-
gations conducted on or directly in conjunction with the intensive study
areas during 1978-79. Individual study reports outline specific job objectives
and procedures and present and discuss current findings in relation to
information obtained previously as well as through supplementary thesis
research projects associated with them.

Several separate publications and reports presented findings or other
information resulting from the Statewide Deer Study. These include:

Hamlin, K. L. and L. Schweitzer. 1979. Observations of coyote
pairs attacking mule deer fawns. J. Mamm. 78(4).

Hamlin, K. L. 1978. Deer, coyote and alternate prey relations
in the Missouri River Breaks Montana. Ann. Conf. N.W. Section,

TWS, Portland, OR, Feb. 1979.

Mundinger, J. G. In press. Reproductive biology of white-tailed
deer in the Swan Valley, Montana. J. Wildl. Manage.

Mundinger, J. G. 1979. The Swan Valley: whitetail country. Mont.

Outdoors 10(5):35-41.

Mackie, R. J., K. H. Hamlin and D. F. Pac. In press. The mule
deer. Chapter 44, ^n: Game, Pest and Furbearing Mammals of
North America. J. A. Chapman (ed.) J. Hopkins Univ. Press.

Mackie, R. J. 1979. "Competition" and the future of wild ungulates
on Montana rangelands. Joint Meeting of the Mont. Chapters Soil
Cons. Soc . of Amer. , Amer. Fisheries Soc., Soc. Amer. Foresters
and The Wildlife Society, Missoula, MT, Jan. 31-Feb. 1, 1979.

While all,. of the studies described are still in progress, and thus most
findings are only preliminary or tentative, results to date have pro-
vided much new information on the general biology and ecology of deer.

Included are a much better and more detailed understanding of distributional
characteristics and patterns and their significance in the ecology of
natural populations. Also included is a better knowledge of reproductive
characteristics and relationships in natural populations as well as the
roles of fawn production and survival, population sex and age structure,
and mortality patterns of both fawns and adults of both sexes as they
influence population size and dynamics annually and in various habitats.

These and other findings provide basis for developing hypotheses concerning
effects of various environmental factors on deer populations and at the same
time have significant potential for use by management. These include the
role of weather, forage supplies, cover, predation, hunting, livestock
grazing management and logging or timber management. Some of these have
been discussed in past or the present reports; others will be outlined in
separate papers and/or in future reports as current concepts are evaluated
in light of continued investigation and findings.

The studies reported in this document required the efforts of numerous
individuals, both with the Montana Department of Fish and Game and in other
agencies. The cooperation of personnel of the U. S. Forest Service, Bureau
of Land Management and the U. S. Fish and Wildlife Service, C. M. Russell
Wildlife Range, has been especially appreciated. Without their combined
interest and effort this study would not be possible. Gratitude is also
expressed to numerous private individuals who have, as landowners, provided
access to their lands and study areas or otherwise provided assistance in
the Investigations.

MONTANA

O fTzTREND OTHER %

STUDY STUDY % ■ ONLY ^ A. SPL #

I

to

Figure A. Current deer studies in Montana.

-5-

JOB TITLE: Population ecology and habitat relationships of white-tailed

deer in coniferous forest habitat of northwestern Montana.

ABSTRACT :

Studies to evaluate factors affecting populations of white-tailed deer
(Odoaoileus virginiana) in the Swan River Valley, Montana were continued
during 1978-79. Data were collected at two checking stations during the
1978 hunting season. Eight marked deer were harvested and reported from
a minimum sample of 136 marked deer known to be alive during the hunting
season. Distribution of hunting pressure and harvest is discussed.

Weights and body measurements of hunter-killed deer indicated growth
patterns. Population parameters were determined from a harvest sample of
145 deer, a trapping sample of 120 deer, a roadkill sample of 27 deer, and
observations of 3,100 deer. Fawns comprised 26% of the harvest during the
either-sex portion of the season and 16% of the total harvest. Fawns com-
prised 42%, 33%, and 27% of the trapping, roadkill, and winter classification
samples, respectively. Yearlings represented 18%, 15%, and 41%, respectively,
of these same mortality factors. Reproductive tracts were collected from
18 adult female deer. No pregnant fawns were examined. Fetal and ovulation
rates of 2%-year-old-and-older does were 1.7 and 1.9 per doe, respectively.
Patterns of reproductive suppression, determined from a sample of marked
does, are discussed. Survival of marked deer also is discussed. The winter
range was a diverse community, occupied by a mature sub-climax forest. Fire
apparently perpetuated this condition. Winter observations of deer typically
occurred in mixed stands of timber, dominated by Douglas fir, western larch,
and lodgepole pine. Several habitat types were represented. Use of natural
openings and clearcuts was minor. Winter food habits are discussed.

Definitive winter home range of marked deer were less than 160 acres. Each
home range included a small activity center. Home range area was influenced
by winter severity. Patterns of sumiiier dispersal, determined from radio-
equipped deer, are discussed. Summering areas of individual deer were
typified by an interspersion of mature coniferous timber with natural openings
and wet sites. Preliminary timber management recommendations are presented.

-6-

JOB TITLE: Population ecology and habitat relationships of white-

tailed deer in coniferous forest habitat of northwestern
Montana.

JOB OBJECTIVE: To determine the environmental requirements of white-tailed

deer and factors regulating white-tailed deer populations
in the coniferous forest habitat of northwestern Montana.

To determine the effects of various potentially competing
land use and management practices upon white-tailed deer
in northwestern Montana.

To develop new and improved guidelines for management of
northwestern Montana white-tail populations and their
habitats.

INTRODUCTION:

The white-tailed deer (OdoaoiZeus V'tvg'Zn'Lana) is the most important big game
species in northwestern Montana where its distribution is closely associated
with the coniferous forest. The Swan River Valley is representative of that
habitat. A study to evaluate factors affecting the Swan white-tail population
was Initiated during November, 1975. During FY-79, the emphasis on obtaining
data basic to distribution, movements, habitat use, and population dynamics
continued. The Swan Valley study is one phase of Montana Statewide Deer
Research.

STUDY AREA

The upper Swan River Valley extends from Swan Lake south to the Swan-Clearwater
Divide (Figure 1) . The valley lies between the Swan Mountains to the east
and the Mission Mountains to the west. The valley is bisected by the Swan
River and by Highway 209 which parallels the river. Most of the winter range
in the upper valley lies between Goat Creek and Condon. Condon is approximately
65 ml southeast of Kalispell. A description of this area was presented by
Hildebrand (1971). The history of game populations in the Swan Valley and
summaries of the early studies are included in Weckwerth 1958, Hildebrand 1971,
and Mundlnger 1976.

Winter extends from mid-November through March. Snow cover generally is
continuous during that period. Thaws and cool rain are typical during January
and February. A mild winter occurred during 1975-76. Winter severity indices
(WSI) (Picton and Knight 1969) , for the period 15 November-31 March, were
caluclated for the latter three winters from the Swan Lake Weather Station
data. The 1976-77 winter was unusually mild (WSI=2,100). Three major snow-
storms occurred and snow persisted from 25 November through 9 April. Yet,
snow accumulations never were heavy and portions of the winter range frequently
were bare. One thaw occurred during January and daily maximum temperatures
were above freezing throughout February and March. The 1977-78 winter was
normal (WSI=12,445) . That year eight major snowstorms occurred and snow persisted
from 17 November through 8 April. Snow accumulations were heavy from late

BIGFORK

-7-

Figure 1. Map of study area.

-8-

December through mid-March. Temperatures were normal. A severe winter
occurred in 1978-79 (WS1=26,457) . Eight major snowstorms occurred and
snow cover persisted from 13 November through early April. Snow accumulations
were heavy through mid-March. That winter temperatures were unusually cold
throughout December and January. The first that did not occur until early
February. Thereafter, temperatures were normal.

METHODS

Hunting Season

Two part-time checking stations were operated during the 1978 hunting season.
Hunters were interviewed to determine hunter origin, drainages hunted, time
hunted, and animals observed. Locations of animals harvested were plotted
on a map, as accurately as possible. Ages of white-tailed deer, mule deer
(Odoooileus hemionus), and elk (Cervus canadensis) were determined by criteria
of eruption and wear of teeth of the lower jaw (Severinghaus 1949; Robinette
et al. 1957; Quimby and Gaab 1957). First incisors were collected from deer
for analysis of annuli in the cementum layer (Gilbert 1966) . Weights and
measurements of deer also were collected.

Production

Information concerning fawn production was determined from the classification
of 3,064 white-tailed deer during the period of December, 1977 through April,
1978. This was supplemented with classification of animals in the harvest,
roadkill, and trapping samples. The reproductive status of 77 m.arked adult
does were determined from ground observations. The reproductive histories of
28 individual does were determined in more than one winter. Reproductive
tracts were collected from 18 adult does.

Distribution and Movements

All observations of deer were plottted according to the legal description of
the location. A general description of the surrounding habitat also was made.
Animals were classified according to age. Attempts were made to classify adult
deer according to sex. Because large numbers of deer were not observed until
the bucks had dropped their antlers, these data were not reliable. Additional
information resulted from the relocation of animals marked for individual
recognition.

Migratory patterns and summer range use data were determined by radio telemetry.
Radio- equipped deer frequently were relocated from a fixed-wing aircraft. This
Information was supplemented with ground relocations of these animals and
reconnaissance of areas used.

Food Habits

Food habits were determined by rumen analysis. Rumen contents were examined
according to Wilkins (1957). Analysis of these data followed the aggregate
percentage method described by Martin et al. (1946).

-9-

RESULTS AND DISCUSSION

Hunting Season

The 1978 hunting season in the Swan Valley extended from 22 October through
26 November. Either-sex deer and elk hunting was permitted until 29
October, thereafter only bucks and bulls were legal game. Weather con-
ditions generally were poor for hunting, except during the last week of the
season when moderate snowfall occurred. The lower Swan checking station
was operated daily during the either-sex portion of the season and on week-
ends thereafter. The Swan Divide station was operated on weekends only.

During the season, 3,684 hunter-trips were recorded. Totals of 145 white-
tailed deer, 15 mule deer, and 32 elk were examined. That included 3,016
hunters, 124 white-tailed deer, 12 mule deer, and 29 elk checked at the lower
Swan station and 668 hunters, 21 white-tailed deer, 3 mule deer, and 3 elk
checked at the Swan Divide station.

According to the 1978 hunter questionnaire, the Swan Valley, Hunting District
130, provided 18,963 man-days of deer hunting, and 12,690 man-days of elk
h^^ting. The indicated harvest was 625 white— tailed deer, 69 mule deer, and
135 elk. Deer hunter success was 18%.

Hunting season parameters, as determined from the questionnaire and the
lower Swan station, are presented for the four hunting seasons in Table 1.
Similar checking station effort occurred in 1976-78, but the station was
operated only on weekends in 1975. The 1978 questlonnare data may not be
wholly comparable with previous years because Hunting District 131 was elimi-
nated and that area included with Hunting District 130 that year. Also, the
format of the questionnaire was changed in 1978.

The questionnaire and checking station data indicated comparable trends in
the harvest of white— tailed deer. Between 1976 and 1978, the indicated rates
of change were similar. Trends in numbers of elk harvested also were similar,
but the magnitude of change was different between data sets and the differences
were not consistent.

The questionnaire indicated greater hunting pressure during 1975 and 1977,
years with larger elk harvests. That trend was not evident in the checking
stations. The questionnaire suggested that hunting pressure varied more
^ibh the numbers of elk hunting trips than with numbers of deer hunting trips.
Elk and deer hunters were not distinguished at the checking station.

The majority of hunters checked were local residents. In all years, residents
of Flathead, Lake and Missoula Counties comprised more than 90% of the
hunters .

Eight marked deer were harvested and reported during the 1978 season. Three of
those were recorded at the checking station and five were reported elsewhere.

A minimum of 136 marked deer left the winter range in spring 1978. Population
estimates were derived from the marked sample, the number of animals checked,
and the questionnaire harvest data (Overton and Davis 1969). Those ranged from

-10-

Table 1. Comparisons of checking station and hunter questionnaire data.

Hunter Days
Questionnaire
Check Station

W-T Deer Harvest
Questionnaire
Check Station

Mule Deer Harvest
Questionnaire
Check Station

Elk Harvest
Questionnaire
Check Station

W-T, Percent Adult Males
Questionnaire
Check Station

Deer Hunters

(Questionnaire)

Percent Deer Hunter

Success (Questionnaire)

1975

1976

40,511

33,606

2,750

3,317

635

523

98

104

70

94

13

15

293

125

51

29

55

74

49

66

4,501

3,673

17

17

1977

1978

39,691

31,653

3,239

3,016

736

625

154

124

86

69

24

12

222

135

39

29

79

79

68

66

4,323

3,779

20

18

5,600 to 10,600, as compared with ranges of 4,000 to 7,900 and 3,500 to 5,700
during 1976 and 1977, respectively. The maximum harvest rate was 11%, as
compared with 13% and 21% during 1976 and 1977, respectively. Several factors
precluded the accuracy of these population estimates. However, they suggested
that current harvest rates have a minor influence on population trend. Further,
trends in total harvest did not follow trends in the population estimates.

The distribution of hunting pressure and harvest, as recorded at the lower
Swan station during 1976-78, is presented in Table 2. The distribution in
hunting pressure was similar during all years. More than half occurred
between North Lost Creek and Dog Creek in the east side of the valley. That
pattern probably reflected the traditions of individual hunters.

During all years, disproportionate higher percentages of white-tailed deer,
relative to hunting pressure, were harvested south of Condon Creek on the
east side and south of Elk Creek on the west side of the valley. The great-
est summer concentrations probably occurred in those drainages, but hunters
did not respond to that availability.

X

interviewirduri^nhe^976!'l977"a^^ determined from the lower Swan checking station

Drainage

1976

1977

Bear Creek-Johnson Creek

107( 7)

^ 50( 3)

6 Mile Creek-Bond Creek

61( 4)

65 ( 4)

West Swan Lake

124( 8)

167(11)

N. Lost Cr. i S. Lost Cr.

153(10)

190(12)

Cilly Creek-Soup Creek

236(16)

258(16)

Squav; Creek-Van I.ake

283(19)

233(15)

Lion Creek-Dog Creek

117( 8)

165(10)

Condon Creek-Smith Creek

95 ( 6)

68 ( 4)

Cooney Creek-Owl Creek

54( 4)

75( 5)

Subtotal - H.D. 130 1

,230(82)

1,271(8:0 :

Woodward Creek-Fatty Creek

61( 4)

71( 5)

Piper Creek-Cold Creek

129( 9)

137( 9)

Elk Creek-Kraft Creek

59( 4)

79(5)

Lindbergh Lake-Beaver Creek

17( 1)

14( 1)

Subtotal - H.D. 131

266(18)

301(19)

TOTAL 1

>

496 1

,572 1

^Percentages of the total in

parentheses .

1978

1976

1977

1978

62( 4)

5( 5)

4( 3)

4( 3)

56( 4)

3( 3)

8( 5)

4( 3)

182(12)

5( 5)

13( 9)

9( 7)

142 ( 9)

7( 7)

5( 3)

8( 7)

271(18)

5( 5)

10( 7)

6 (5)

184(12)

13(13)

20(13)

16(13)

177(12)

8( 3)

20(13)

18(15)

66( 4)

18(13)

10( 7)

12(10)

74( 5)

10(10)

11( 7)

11( 9)

,214(80)

74(73)

101(67)

88(72)

85( 6)

K 1)

8( 5)

5( 4)

119( 8)

10(10)

17(11)

11( 9)

74( 5)

12(12)

21(14)

17(14)

16( 1)

4( 4)

4( 3)

2( 2)

294(20)

27(27)

50(33)

35(28)

1,508

101

151

123

Mule Deer

Elk

19/6

1977

1978

1976

1977

1978

K 4)

K

3)

K 3)

2(13)

7(29)

K 8)

K

3)

3( 8)

7(24)

4(27)

4(17)

K 8)

3(

9)

5(14)

4(14)

K 7)

K 4)

2(

6)

5(14)

3(10)

10(31)

4(10)

4(27)

4(17)

3(25)

13(36)

6(21)

2(13)

K 8)

6(21)

K 7)

K 8)

2(

6)

2( 7)

14(93)

17(71)

7(58)

19(59)

31(86)

28(97)

K 7)

4(17)

2(17)

6(19)

K 3)

2( 8)

K 8)

3(

9)

K 3)

K 4)

2(17)

3(

9)

3( 8)

1( 3)

K

3)

1( 7)

7(29)

5(42)

13(41)

5(14)

K 3)

15

24

12

32

36

29

-12-

The distribution of hunting pressure in the Swan during 1976 appeared to
be related to the distribution of the elk harvest. That relationship was
not evident in 1977 and 1978.

Distributions recorded at the Swan Divide station are presented in Table
3. The most noteworthy trend was a decline in hunting pressure with in-
creasing distance north from the Swan— Clearwater Divide.

A comparison of the white-tailed deer harvest distribution during 1978 and
previous years is presented in Table 4. Noteworthy changes since 1959 in-
cluded a reduction in the proportion of the harvest taken between Squaw
Creek and Dog Creek, an average of 47% during 1948-1959 as compared with
25% in 1978; an increase in the proportion of the harvest taken from south
of Condon, an average of 22% during 1948-59 as compared with 41% in 1978;
and, a broader distribution of the harvest. Those differences reflect an
increase in the road density throughout the valley. A probably decline in
the density of deer which summers on or near the winter range was also
Indicated.

Weights and Measurements

Average hog-dressed weights and body measurements were collected at the check
stations. Body measurements included total length, from the tip of the nose
to the base of the tail; height at the shoulder; and, length of the hind
foot. Data for the four hunting seasons were pooled (Table 5).

Weights and measurements of females suggested that does continued growth
in wieght through hh years. Growth in body size increased significantly
through 2% years. Differences in body measurements between 2^2- and 3%-year-
old does and between 3%- and 4%-year-old does were not statistically sig-
nificant, but the average length of 415-year-old does was significantly
greater than that of 215-year-olds. It was probable that the paired t-test
was not sensitive to small, biologically significant differences. Variances
were large while sample sizes of 315-years and older age-classes were small.

Significant increases in both weight and body size of males continued through
5I5 years. Males evidenced large variations in size and weight within in-
dividual age classes. The range of yearling weights was 95-160 lbs and the
range of total lengths for this age class was 122-170 cm. Weights and
lengths of 215-year-old males ranged between 110-180 lbs and 135-168 cm,
respectively. The range of weights of 315-year-olds was 144-213 lbs while
lengths ranged between 147-173 cm. In the 415-year-old age class, weights
ranged between 145-215 lbs and lengths between 142-178 cm. A portion of this
variation may have resulted from the time that each animal was harvested
relative to the onset of the rut. Variations in measurements of males also
seemed to be related to individual differences in growth potential because
the differences were apparent at a young age.

Hog-dressed weights of Swan Valley white-tailed deer were heavier than average
weights for Montana (Mackie 1964) . They also were heavier than those reported
for the Fisher River-Wolf Creek area in northwest Montana (Firebaugh et al.
1975).

Table 3. Distribution of hunting pressure and harvest, by drainage, as determined from the Swan Divide
checking station interviews during the 1977 and 1978 hunting seasons.

Drainage

Hunting

Parties

W-T

Deer

Mule Deer

Elk

1977

1978

1977

1978

1977

1978

1977

1978

Bear Creek-Johnson Creek

6 Mile Creek-Bond Creek

West Swan Lake

3(

1)1

K 2)

North & South Lost Creeks

4(

1)

4( 1)

2( 4)

K 5)

K 7)

Cilly Creek-Soup Creek

5(

1)

3( 1)

Squaw Creek-Van Lake

7(

2)

3( 1)

1

Lion Creek-Dog Creek

21 (

5)

19( 7)

3( 6)

2(10)

Condon Creek-Smith Creek

36 (

9)

17 ( 6)

4( 8)

3(14)

1

Cooney Creek-Owl Creek

135(34)

68(23)

21(40)

2(10)

1

1

8(53)

1

Subtotal H.D. 130

211(53)

114(39)

31(60)

8(38)

3

1

9(60)

1

Woodward Creek-Fatty Creek

3(

1)

2( 1)

Piper Creek-Cold Creek

22 (

6)

18( 6)

2( 4)

K 7)

Elk Creek- Kraft Creek

70(18)

56(19)

12(23)

8(38)

1

Lindbergh Lake-Beaver Creek

90(23)

102(35)

7(13)

5(24)

5(33)

1

Subtotal H.D. 131

185(47)

178(61)

21(40)

13(62)

0

0

6(40)

2

Total

396

292

52

21

3

1

15

3

^Percentages of the total in parentheses.

Table 4.

Comparison of the percentage of the white— tailed deer harvest, by drainage, from checking
station data, 1948-1978.

1948^

1949^

I957I

1958^

I959I

19622

19752

19762

19772

1977^

1978

Sample size

48

51

255

196

196

39

91

101

151

203

144

Drainage

East Swan Lake

27

18

4

8

3

8

9

8

8

6

6

West Swan Lake

2

5

3

2

5

9

7

7

North and South Lost Creeks

4

6

5

1

8

7

7

3

3

6

Cilly Creek-Soup Creek

4

6

7

4

7

8

8

5

7

5

4

Squaw Creek-Van Lake

31

31

21

19

32

21

22

13

13

10

11

Lion Creek-Dog Creek

23

16

22

13

25

15

8

8

13

11

14

Condon Creek-Smith Creek

4

2

5

11

5

10

22

18

7

7

10

Cooney Creek-Owl Creek

8

10

18

14

9

13

6

10

7

16

9

Subtotal H.D. 130

98

86

82

76

87

85

82

73

67

65

67

Woodward Creek-Fatty Creek

2

12

5

6

9

3

4

1

5

4

3

Piper Creek-Cold Creek

4

8

1

3

9

10

11

9

8

Elk Creek-Kraft Creek

2

4

2

1

10

4

12

14

16

17

Lindbergh Lake-Beaver Creek

4

8

2

4

3

5

5

Subtotal H.D. 131

2

14

18

24

13

15

18

27

33

35

33

^Data summarized from two checking stations.

Data summarized from lower Swan checking station only.

-15-

Table 5. Average hog-dressed weights and body measurements of white-tailed
deer harvested in the Swan Valley, 1975-78.

Sex Age

Weight

(lbs)

Height

(Cm)

Length

(Cm)

Hind foot
(Cm)

99

58

114

78

41

1

h.

98*

133*

88*

46*

2

1

h

106*

139*

91*

47*

3

h.

111

142

91

47

4

h

122*

144

92

47

5

121

133

100

46

6

h.

113

143

91

47

7

h

109

135

92

46

8

h

123

144

91

47

9

+

118

146

94

47

dtr

h

65

116

81

42

1

h

114*

141*

94*

48*

2

h

147*

151*

99*

50*

3

h

159*

158*

103*

50

4

h

176*

157

103

50

5

%

200*

168*

103

51*

6

h

181

164

104

49

7

h

186

166

104

50

8

h

192

165

102

52

9

+

177

159

104

49

^Significantly greater,
^Sample size of one.

P<0.05,

than preceding number

in column.

Age Data

The age distribution of the 1975-78 white-tailed deer harvests is presented
in Table 6. Animals were assigned to fawn, yearling, and 2%-year-old classes
according to criteria of eruption-wear (Severinghaus 1949). Older deer were
assigned to age-classes according to an analysis of the dental cementum in
the first Incisor (Gilbert 1966) , except that four deer were assigned to the
3^-year-old class by eruption-wear because the cementum analyses probably were
incorrect. In addition to the animals for which age was determined, 30, 7, 7,
and 9 unclassified adult deer were checked during the four respective hunting
seasons. Conclusions regarding the 1975 adult age structure must, therefore,
be tentative.

-16-

Table 6. Percent composition, by age-class, of the white-tailed deer harvest
in the Swan Valley, 1975-78.

Age-

Females

Males

Total

Class

1975

1976

1977

1978

1975

1976

1977

1978

1975

1976

1977

1978

h

30

14

31

26

14

12

11

12

20

12

18

16

1 %

13

57

17

31

33

39

46

45

25

43

37

41

2 ig

17

14

25

15

25

22

16

22

22

21

19

20

3 %

9

5

10

8

4

11

9

8

3

9

10

4 is

9

5

9

8

10

2

3

7

10

1

5 is

2

5

8

3

1

5

5

2

1

5

6 ig

9

5

3

3

4

3

3

4

3

1

7 ig

9

5

6

3

2

7

2

3

8 ig

5

3

5

6

4

3

4

1

1

9 ig

1

1

1

1

10 ig

3

1

0

11 ig

1

1

12 ig

13 ig

4

2

14 ig

2

1

Sample

Size

23

21

64

26

36

76

135

97

59

97

199

136

Classification data suggested that fawn production was greater in 1976-77 than
in 1975-76 (Table 9). This trend was not evident in the harvest data. That
a smaller percentage of fawns was harvested during 1976 probably resulted from
the large number of unclassified adults in the 1975 sample and yearlings in
the 1976 season, and the more restrictive regulations that began in 1976. The
highest rate of fawn production occurred during 1976-77 and that was consistent
with the harvest trend. The lowest rate of fawn production occurred in 1978-79,
but that was not indicated by the harvest.

The proportion of fawns in the male samples was influenced by the length of the
either-sex season. Fawns comprised 29, 29, 24, and 29% of the male harvest
during the either sex protion of the four hunting seasons, respectively.

Harvest data suggested reasonable survival of young. The 1975, 1976, and 1977
cohorts were well represented in both sex-classes during subsequent hunting
seasons. Trends of older cohorts were difficult to interpret from these data.

Yearling males consistently were the dominant sex/age class. Harvests probably
were biased in favor of this group.

-17-

Percentages of 3%- and 5%-year-old deer In the harvest may not have been
representative of the population age-structure. Harvests probably were
biased against these age-classes. Discrepancies also may have resulted from
errors in age assignments.

Jaws were collected from adult white-tailed deer during the hunting seasons
and from roadkills and trap casualties. They permitted a comparison between
eruption-wear and dental cementum as methods for determining the age of white-
tailed deer (Table 7). The sample incuded five known-age animals. The ages
of three ZJ^-year-olds were correctly determined by eruption-wear; while one was
incorrectly assigned to the yearling class by dental cementum. Both methods

correctly determined the age of a 3%-year-old deer. The age of a S^-year-old

deer was correctly determined by dental cementum; that deer was assigned to the
3J5-year-old class by wear characteristics. Two other marked deer of unknown
age were included in the sample. The age of one was estimated as 4ig years in

March 1976. She was recovered in February 1979. At that time, ages of S^j-years

and Ilk-years were determined by wear and dental cementum, respectively. The
other deer was assigned to the SJg-year-old class in March 1976. When she was
recovered in October 1977, the age determinations were b^j-years and S^s-years
by wear and dental cementum, respectively.

Table 7. Comparison of age determinations by tooth eruption and wear

with age determination by dental cementum.

Assigned Age by
Dental Cementum

Assigned Age by Tooth Eruption and Wear

Sampl

Size

2i

3i

?i

6^—

7i 8^

2

2

68

h

72

3^

h

28

32

hh

19

3

22

6

h

1

11

2

6

7

15

7i

U

U

1

9

Si

5

u

2

11

1

1

lOi

2

1

1

h

Hi

1 2

3

12i

1

1

2

i3i

1

1

lUi

1

1

-18-

Erupt ion-wear Is assumed to be completely reliable through ZJ^-years.

Fawns and yearlings are accurately determined by the characteristic com-
binations of deciduous and permanent dentition that Severinghaus (19A9)
described. Deer of 2%-years have a complete set of adult teeth and the lack
of wear and staining are very distinctive. Ages of older deer, as determined
by wear characteristics, consistently were younger than those indicated by
dental cementum (Table 7). Deer from the Swan Valley apparently do not
develop dental wear patterns as rapidly as those described by Severinghaus
(1949) .

Dental cementum probably is the more reliable technique for older animals,
but this method was not always accurate. The ages of 10 of 106 animals in
the 25^- and SJ^-year-old classes were Incorrectly determined by dental
cementum (Table 7). This suggested that errors also occurred in the older-
age classes, but wear characteristics were not an adequate crosscheck for
these deer. Few examples of tooth sections, in which each annulation was
determined with certainty, were encountered. Typically, annuli were incom-
plete in portions of the section and compressed in other portions. That count
of annuli with the best agreement between two sections from the same tooth was,
therefore, assumed to be indicative of the age of the animal.

Fawn Production

Observations of 3,100 white-tailed deer were made between January and March
1979. Of these, 3,064 were classified to fawns or adults (Table 8). The
data indicated a fawn/adult ratio of 37.7/100, or a population comprised of
27.4% fawns. The recruitment rate averaged 29% for the period 1976-79. The
lowest recruitment rate was recorded during 1978-79. Recruitment rates were
higher and more variable in prior years (Table 9) .

A sample of 113 deer was observed during the 4 replications of the upper
Swan Valley trend route. The recruitment rate indicated in that sample
(Table 8) was lower than that derived from observations throughout the
winter. In 1977 and 1978, the estimates of recruitment derived from the
trend routes had been comparable to those from observations throughout the
winter (Mundinger 1978).

Individual adults that were accompanied by fawn(s) were presumed to be
does. Those animals were compiled to determine the ratio of twin/ singleton
litters. Twinning indices were 0.32, 0.42, 0.29, and 0.19, respectively,
for each of the winters, 1976-79.

Fawn/adult and fawn/doe ratios from animals harvested during the 1978
either sex hunting season were 35/100 and 69/100, respectively (Table 10).
The ratios of adult males/adult females was 94/100.

Data gathered during 1978 Indicated that yearlings comprised a substantial
proportion of the adult population. This was consistent with the high
recruitment rate recorded during 1977-78. Twelve of 32 (38%) adult females,
44 of 90 (49%) adult males, 56 of 122 (46%) adults, and 41% of the total
harvest were yearlings. Respective percentages during 1978 were 24, 52. 44
and 37.

-19-

Table 8. Monthly classifications of white-tailed deer in the Upper Swan River
Valley during winter, 1979.

Month

Total

Adults

Fawns

Unci .

ff/100 Ad.

% ff

January

553

395

147

11

37

27.1

low^

33

9

27

high^

22

9

41

February

1,572

1,125

426

21

38

27.5

low

40

10

25

high

17

10

59

March

975

704

267

4

38

27.5

low

45

10

22

high

27

19

70

1979 Total

3,100

2,224

840

36

38

27.4

Trend Route

113

85

28

33

24.8

1978 Total

4,198

2,707

1,295

196

48

32.4

1977 Total

3,743

2,429

1,010

304

42

29.4

1976 Total

2,269

1,519

600

150

39

28.3

^Daily classification with the lowest fawn/adult ratio during the month.
Daily classification with the highest fawn/adult ratio during the month.

Classifications of the 1979 trapping samples are compared with previous
winters in Table 11 while those of roadkllled deer are presented in Table 12.

Several sources provided estimates of the fawn sex ratio (Table 13). The
estimates were variable within and between years and variations were not

consistent. Apparently, sample sizes were insufficient to adequately assess
this parameter.

Reproductive tracts were collected from 18 adult females (Table 14), seventeen
were pregnant. Fetal and ovulation rates both were 1.0/yearllng doe and were
j 1.9/doe, respectively, for older does. Fetal rates were 1.3/doe

and 1.8/doe for yearlings and adults, respectively during 1978. Higher
potential productivity that year may have resulted from the extremely mild

winter incurred during 1977. Three female fawns were examined and none were
pregnant .

-20-

Table 9 .

White- tailed
1958- 1979.

deer fawn/adult ratios in

the Swan River Valley,

Year

Adults

Fawns

Fawns/

100 adults

Percent

Fawns

1958

167

99

59

37

1959

207

68

33

25

1960

77

30

39

28

1961

19

8

42

30

1962

80

33

41

29

1963

59

31

53

34

1964

234

90

38

28

1965

188

108

57

36

1966

33

17

52

34

1967

51

26

51

34

1968

30

26

80

46

1969

122

55

45

31

1970

249

112

45

31

1971

66

28

42

30

1972

42

13

31

24

1976

1,519

600

39

28

1977

2,429

1,010

42

29

1978

2,707

1,295

48

32

1979

2,224

840

38

27

-21-

Table 10. Either-eex htinting season classifications.

I ear

Fawns/ 100 Adults

Fawns/ 100 Femaies

Adult Males/ 100 Adult Females

1975

M

1+5

87

93

1976

27

55

100

1977

36

70

91+

1978

35

69

91+

Table

11. Percent
trapping

composition by
sample .

sex

and age

-class

of white-tailed (

ieer

Age-

. 7

Females

Males

Total

Class

1976

1977

1978

1979

1976

1977

1978

1979

1976

1977

1978

1979

%

24

29

26

28

55

68

66

69

35

40

39

42

ih

12

17

22

17

12

23

18

18

12

19

20

1

18

2h

14

9

17

9

7

5

7

3

12

8

14

7

1 3h

9

12

14

15

2

0

9

3

7

9

12

11

4+

41

33

22

31

24

5

0

8

35

25

14

23

Sample

Size

76

58

88

81

42

22

44

39

118

80

132

120

1 j i :

Table 12. Percent composition by sex and age-class of white-tailed deer
road-kill sample. ’

Age-

Females

Males

Total

Class

1^

1977

CO

1979

19^

1977

1978

1979

197^

1977

1978

1979

25

28

35

32

29

33

77

38

27

30

1+9

33

25

6

10

11

11+

11

9

25

20

7

10

15

2i-

17

13

16

11+

33

25

7

22

9

19

3^

13

28

13

11

29

5

20

19

10

7

,

38

22

29

32

11+

22

9

13

27

22

23

26

Sample

Size

8

18

U8

19

7

9

22

8

15

27

70

27

-22-

Table 13.

Comparative

estimates of fawn sex ratios

(99 /cT) .

Soiirce

Year

In utero

Check station

Trapping

Road-kill

1975-76

l.U:l

0.8:1

1.0:1

1976-77

0.5:1

0.3:1

1.1:1

1.7:1

1977-78

0.5:1

1.3:1

0.8:1

1.1:1

1978-79

1.1:1

0.8:1

0.9:1

2.0:1

1979-80

0.U:1

The potential productivity of the Swan Valley population is depicted in
Table 15. These data were summarized from 1970 (Hildebrand 1971) and 1976-
79 collections. Yearlings comprised the youngest breeding age-class. Ninety-
six percent of all adult does, yearling and older, was pregnant. The fetal
rate for all females was 1.5/doe and 1.6/pregnant doe. The highest fetal rate
was recorded for 3%-year-old does, while the highest ovulation rate occurred
in the oldest age class. Comparisons with other studies (Cheatum and
Severinghaus 1950; Ransom 1967; Roseberry and Klimstra 1970) indicated that the
reproductive potential of the Swan Valley population is less than that reported
for the species.

The reproductive performance of 19, 45, 61, and 77 individually marked does
was determined from field observations during the four winters, respectively
(Table 16). Most of these determinations were made between mid-January and
early April. Differentially greater fawn mortality, as compared with adults,
had not been detected from classifications (Table 8). Repeated observations
of several doe-fawn associations also indicated high fawn survival through
this period. Therefore, production rates, as determined from this sample,
were estimates of recruitment.

Reproductive success of collared does was consistent with the low recruitment
rate for the population as a whole. Cumulatively, 86 or 156 adult, 2h years and
older, does successfully reared 97 fawns. Productivity was 62 fawns/100 does,
■phat represented a loss of 59% of the potentxal fawn production.

None of the yearlings in this sample was observed with fawns. This was con-
sistent with the lack of pregnant fawns in the sample of reproductive tracts.

Forty— six percent of the 2%— year-old does was observed with fawns (Table 16) .
This contrasted with the pregnancy rate of 94% for the yearling age class
(Table 15). Potential production for this class was 120 fawns/100 does. The
observed fawn/doe ratio of 46/100 represented a 61% fawn loss between pregnancy
and the subsequent winter.

-23-

Table 14. Summary of 1979 reproductive tract collections.

Date

Age

C. L. of
Pregnancy

Embryos

C. R.

Length (cm)

Weight (gm)

nil

1%

1

icr

16.3

123.0

nil,

1%

0

Not Pregnant

nil

1^

2

Id"

22.5

321.0

l9

21.1

285.0

1/23

2h

1 unci.

3/5^

1\

19

23.2

378.0

1/20

bh

2

Id-

5.7

8.1

2/11

bh

2 unci.

3/9

bh

1

19

23.3

406.0

3/14

bh

19

■ r

1 unci.

4/6

bh

2

1 unci.

Id*

31.3

1002.0

3/9

4%

Pregnant

nil

5Js

2

19

7.6

12.8

Id"

7.6

12.6

2/25

5Js

Pregnant

nib

5%

Pregnant

nif,

hh.

2

Id"

17.6

150.2

IcT

17.7

155.6

3/5^

6%

Id*

nik

llh

2

Id-

21.1

28.2

Id*

20.5

27.3

2/8

llh

2

IcT

13.5

93.0

Id-

13.8

102.0

^Reproductive tract incomplete.

-24-

Table 15. Reproductive potential, by age-class, as determined from 1970^,
1976, 1977, 1978 and 1979 collections of reproductive tracts in

the

Swan Valley.

Sample

Percent

Fetuses

Fetuses

Per

Ovulation

Age

Size

Pregnant

Per Doe

Pregnant

Doe

Rate"^

h

36

0

ih

17

94

1.2

1.3

1.3

2%3

16

94

1.4

1.5

1.8

3^2

25

100

1.8

1.8

1.9

4%

16

94

1.7

1.8

2.0

5+

17

94

1.6

1.8

2.1

^1970 data from Hildebrand (1971).

^Ovulation rates from 1976-79 data only.

^The non-parous female in this sample had aborted (Hildebrand 1971) .

Forty-eight percent of the 3%-year-old does was observed with fawns, in
contrast with the 94% pregnancy and 1.4/doe fetal rates recorded for 2h~
year-old does. None of the does in that group had twins. The fawn/doe
ratio for 3^— year— old does represented a 65% fawn loss.

Fifty-nine percent of the 4l2-year-old does was observed with fawns; none
had twins. That contrasted with a 100% pregnancy rate and the fact that
3is-year-old does evidenced the highest fetal rate, 1.8/doe. The observed
fawn/doe ratio represented a 68% fawn loss in the 4!^-year-old age class.

The high rate of fawn loss for this class, despite a higher rate of repro-
ductive success, resulted from the high fetal rate in comparison with the
lack of twin fawn litters.

Sixty-three percent of all does 5%-year-old and older was observed with
fawns. This group included the only females seen with twins. Eighteen
percent of the old does and 28% of those which successfully reared fawns were
observed with twins. Those observations contrasted with a pregnancy rate of
94%, a fetal rate of 1.64/doe, and a potential of 64% twin fawn litters
for 4H — year-old does. The rate of fawn loss was 51% for old does.

The reproductive performance of individuals during two or more successive
years was determined from observations of 28 adult does, 2is-years-and-older
(Table 17). The sample provided 39 cases of 2-year reproductive histories.
Does successfully reared fawns only in alternate years in 23 (59%)^ of the
cases. There were 9 (23%) cases of reproductive failure and 7 (18%) cases
of reproductive success during two consecutive years. Generally, does which
failed in consecutive years were younger animals while those which produced
fawns in consecutive years were older.

-25-

Table 16.. Reproductive performance of marked does by age-class.

Age- Class

ih

2%

3lg

4^5

5+

Total

2+

1976

Number of does

3

3

2

5

6

19

16

Number of successful does

0

1

1

3

5

10

10

Percent success

33

50

60

83

53

63

Number fawns

1

1

3

7

12

12

ff/100 does

33

50

60

117

63

75

1977

Number of does

13

5

8

2

17

45

32

Number of successful does

0

1

3

2

10

16

16

Percent success

20

38

100

59

36

50

Number fawns

1

3

2

15

21

21

ff/100 does

20

38

100

88

47

66

1978

Number of does

14

18

10

8

11

61

47

Number of successful does

0

8

8

5

8

29

29

Percent success

44

80

63

73

48

62

Number fawns

8

8

5

10

31

31

ff/100 does

44

80

63

91

51

66

1979

Number of does

16

15

11

7

28

77

61

Number of successful does

0

9

3

3

16

31

31

Percent success

60

27

43

57

40

51

Number fawns

9

3

3

18

33

33

ff/100 does

60

27

43

64

43

54

Total

Number of does

46

41

31

22

62

202

156

Number of successful does

0

19

15

13

39

86

86

Percent success

46

48

59

63

43

55

Number fawns

19

15

13

50

97

97

ff/100 does

46

48

59

81

48

62

-26-

Table 17.

Summary of

reproductive

histories for 28 individual

marked does.

Deer No.

Estimated

Age

in 1976

Number
of fawns
in 1976

Number Number

of fawns of fawns

in 1977 in 1978

Number
of fawns
in 1979

4-76

5'^

2 0

1

27-76

0

0 1

1

29-76

5%

2

2

36-76

3I5

0

1

1

41-76

6^2

1

1

44-76

1

0

49-76

4%

1

0

50-76

5J2

2

0

51-76

2%

0 1

0

55-76

6%

1

1

1

60-76

4is

0

0 0

1

62-76

1

0

69-76

6J5

0

1 1

75-76

4I2

1

0 1

79-76

2h

0 1

1

85-76

2^5

0

0 0

86-76

ih

0

2 1

92-76

hh

0 1

100-76

6^5

2

0

107-76

5^5

1

0

6-77

0

0

25-77

0

0

60-77

2h

1 0

0

27-78

2%

1

0

41-78

1%

1

0

48-78

0

0

56-78

1^5

1

0

103-78

h

1

0

^ Known-aged does.

-27-

Ten does provided 12 cases of 3-year histories. There were two cases
of reproductive failure In three consecutive years. Five cases each of
successful production In 1 of 3 and 2 of 3 years were recorded. In no
case did a doe successfully rear young during three consecutive years.

Further evidence of alternate year production by Swan Valley white-tails
was provided by the reproductive rates recorded for Individual cohorts
during consecutive years (Table 18). The most notable was the 1973 cohort,
does that were 2%-years-old In 1976. The sum of success rates In any two
consecutive years did not exceed 100%. Comparable data for older cohorts could
not be tabulated because of errors In age determinations and small sample
sizes .

Table 18. Percent reproductive success In consecutive years by Individual
cohorts.

Cohort

Year

1976

1977

1978

1979

1971

60

40

1972

50

100

1973

33

38

63

33

1974

20

80

43

1975

44

27

The net productivity of the Swan Valley population was less than Its
potential and the difference accrued from several sources. Fetal rates for
all age classes were less than the species potential. Reproductive failures
were typical during the first two breeding cycles. Although does In their
second and third breeding cycles frequently conceived twins, the does did
not successfully rear twins. Fetal rates declined In the older age classes.
Although old does were more successful than younger does In rearing twins,
only 11 of the potential 40 twin fawn litters were observed with the old
does In the sample. Also, one-third of the old does failed to rear any
fawns. Reproductive success only In alternate years was typical In all age
classes.

Less than half of the conceived fawns was reared and recruited to the adult
population. How this loss occurred was not defined; however, neonatal mor-
tality, as a result of nutritive failure (Verme 1962), probably was an
Important factor. The strongest evidence for nutritive failure was the
tendency for alternate year reproductive success. Verme (1967, 1969) de-
scribed a situation In which reproductive failure, due to nutritive failure,
by does on Inadequate winter nutrition, contributed to reproductive success

-28-

in the following year. Murphy and Coates (1966) indicated that the post-
partum survival of fawns was reduced by low levels of protein in the diet
of pregnant females. Salwasser et al. (1978) estimated 50-70% mule deer
fawn mortality within 4 weeks of birth. They suggested that losses were
related to the nutritional quality of deer habitats during the last tri-
mester and lactation periods.

No major cause of fawn mortality was observed in the field and neonatal
mortality would have been difficult to detect directly. Verme (1962)
observed high survival among fawns which had survived the first 48 hours
of live. O'Pezio (1978) observed fawn losses of 22% and 19% for does 2-
years-old and 3-or-more-years-old , respectively, during the first 2 weeks
of post-parturition. Fawn losses were negligible during the two month
period thereafter. Mortality factors were not defined.

Verme (1977) suggested that the ratio of fawns to adult does, 2%-years and
older, in the either sex harvest was correlated with estimated neonatal
losses. He associated harvest ratios of 1.23 fawns/doe and 0.64 fawn/doe
with neonatal mortality estimates of 10% and 50%, respectively. Harvest
samples from the Swan Valley were too small to compare with his data.

However, a ratio of 0.62 fawn/adult doe was observed with the composite
sample of marked does. This was associated with an estimated 59% loss of
potential fawns.

A relationship between productivity and age was suggested. Weights and body
measurements of hunter-killed deer indicated that females did not attain
physical maturity until they were four-year-olds (Table 5). Thus, does
were sexually mature as yearlings, but they continued to grow through their
third breeding cycle. Reproductive suppression in physically immature does
was evidenced by reduced fetal rates for yearlings and 2%-year-olds and
reduced rates of reproductive success for 2^- and 34-year-old does. It
therefore appeared that the immature doe was faced with a physiological
predicament. Requirements are high for both growth and production and one
must have occurred at the expense of the other. Verme (1962:21) stated that
the physiological stress of the first pregnancy probably was proportionally
greater than in pregnancies of older does. Robinette et al. (1973) indicated
that fawn losses were heavier for primaparous, as compared with multiparous,
mule deer does. Further, they suggested that mule deer females must ordinarily
weigh 41 kg (90 lbs), or more, for successful breeding.

A relationship between winter severity and productivity was also suggested.

A mild winter occurred in 1976 and an unusually mild winter occurred in 1977.
During 1978, the yearling fetal rate was 1.3/doe, as compared with a rate
of 1.1/doe for the remaining yearlings in the sample. Similarly, the fetal
rate for 24-years-old and older was 1.8 in 1978, as compared with 1.6 for
the remaining animals. Further, net productivity by 2%- and 34-year-olds,
does in their first two breeding cycles, was substantially greater following
the 1977 winter (Table 16). Julander et al. (1961) indicated that productivity
of the youngest breeding age class reflects range condition more sensitively
than that of the older age classes. That the youngest breeding class tends
to be the most variable also might be Inferred from other studies (Ransom 1967,
Verme 1969, Hesselton and Jackson 1974). Verme (1977) indicated that neo-

-29-

natal fawn loss was a function of winter severity. Mackie et al. (1976)
indicated that fawn production and survival of mule deer in the Bridger
Mountains, Montana, was directly related to the extent to which deer were
able to use all portions of the winter range and all forage resources.

During the 1977 winter, white-tailed deer were widely dispersed and
occupied areas that were peripheral to the usual winter distribution
(Mundinger 1977).

The high rate of production recorded for 2%-year-old does during 1979,
following the normal winter in 1978, was an apparent inconsistency.

However, this cohort was reared by does which had experienced the 1976
winter. Moen (1978) indicated that the effect of an early spring on pop-
ulation dynamics would be most conspicuous when the subsequent fawn crop
began to contribute their own fawns to the population. Further, these
does were fawns during the 1977 winter. It seemed logical that this
cohort experienced unusually good growth in response to the 1976 and 1977
winters. That, in turn, was reflected in the productivity by this cohort
during 1978-79.

Alternate year reproductive success was characteristic of the population.

Thus, reproductive success by older does was less responsive to the mild
winters, however, twinning rates may have been an indicator of range
conditions. The highest twinning index was recorded in 1977. Twinning by
older does was comparatively high in 1973 (Table 16), though this was not
reflected by the twinning index that year because a large number of single
fawn litters had been reared by 2%- and Sij-year-old does. The twinning index
was lowest in 1979. That year the index reflected a disproportionately
large number of single fawn litters produced by 2is-year-olds and a low rate
of twinning by old does. The 1976 twinning index was not consistent with
observed productibity for old does that year. That may have resulted because
the sample of marked does was small in 1976.

It was hypothesized that the observed patterns of reproduction were mech-
anisms which operated to maintain stable levels of fawn production in tne
Swan Valley herd. Production operated together with other population
phenomena to maintain population stability.

Annual variation in total fawn recruitment was largely a function of the
reproductive success rate of young does and the population age structure.

With a normal age distribution, yearlings comprised the single largest
group of sexually mature females, and that group contributed substantially
to the potential annual increment. Data presented by Severinghaus and Cheatum
(1956:101) indicated that more than 40% of the anticipated fawn crop in
western New York was produced by yearlings. Yet, the ability to conceive
fawns did not necessarily indicate an ability to successfully rear them.
Reproductive success by 2is-year-old does in the Swan Valley was low and
variable. The value of the potential production by that age class varied
accordingly.

The rate of reproductive success tended to be fixed for 3+ -year-old does
because fluctuations were dampened by alternate year production. Variations
in the data were probably artifacts of sample size. Because success rates
tended to be fixed, contributions of prime-aged does to the annual
increment varied more with the strength of the individual cohorts.

-30-

Potentlal production declined with increasing age because the size of
those cohorts declines. The disparity between potential and net pro-
duction was lowest in the old age classes. Annual variation in the
contribution by old does occurred because of fluctuations in the twinning
rate, rather than from fluctuations in reproductive success. Moreover,
alternate year production was less rigid in the older age classes. There-
fore, the contribution by old does to the annual increment was proportionally
greater than the number of these animals in the population and may have been
essential during poor production years and periods of population decline.

Despite the tendency for population stability, the population retained the
potential for rapid growth when young animals were producing. A year which
favored recruitment will have its greatest Influence on 2%-year-old does .
Production by 3%-year-olds will also be favored because most of these
animals had failed the previous year. Such was the case during 1977-73,
a year which followed an unusually mild winter. During 1978, the reproduc-
tive success rates doubled for 2h~ and 3%-year-old does (Table 16) and the
estimated recruitment rate increased, as compared with 1977 (Table 9) .

As the population increased, further increases occurred with greater dif-
ficulty. This must have occurred because of increases in the percentages
of yearlings, which did not rear young, and 215-year-olds, which reared young
at a reduced rate. Also, success rates of 3%- and 4%-year-old does, which
had reared young at an above-average rate the previous year, will decline
due to alternate year production. Thus, during 1978-79 success rates
declined by 66% and 32%, respectively, for these age-classes (Table 16) and
the recruitment rate for the population also decreased (Table 9) . Recruit-
ment actually was higher during 1978-79 than previously was anticipated
because the high rate of reproductive success by 2I2— year— olds was not expected.
Mackie (1978) indicated that the rate of Increase in two different mule deer
populations was progressively damped because the proportion of fawns lost
to attrition increased as fawn crops increased.

It was noteworthy that similar recruitment rates were observed in all years
except in 1977-78. Verme (1962) indicated that a large residual herd needed
very little net population increment to perpetuate itself. Despite a 59%
loss of potential production, an average recruitment rate of 29% was recorded.
That rate appeared to provide adequate numbers of young to replace annual
attrition. The population appeared to be capable of achieving 29% recruit-
ment through a variety of strategies.

Survival of Marked Deer

Four hundred and eleven white-tailed deer have been captured and marked
for individual recognition during the four winters of this study. Of those,
129 were known to be alive at the time of spring dispersal in 1979. Numbers
of known survivors within the yearly samples are presented, by year, in
Table 19.

Sixty marked deer have been known mortalities. They included 24 hunting
losses. 19 roadkills, 5 winterkills, and 7 from other causes (Table 20).

-31-

Table 19. Number of known survivors within yearly samples of marked deer.

Sample

Year

Sample

Size

1976

1977

1978

1979

1976

115

85

56

30

16

1977

69

39

22

13

1978

118

92

44

1979

109

56

Table

20, Known

mortalities

of marked

white-tailed deer,

Year

Sample

Hunting

Road-kill

Winter-kill

Coyote-kill

Other

1976

1976

5

1

1

1

1

1977

1976

9

2

2

1

1977

2

2

1

1

1

1978

1976

3

1977

3

3

1

1978

5

3

2

2

1979

1976

1

1

1977

1

1978

1979

3

1

1

TOTAL

24

19

5

5

7

The fate of 222 deer had not been determined by spring 1979 (Table 21) .

The group Included animals which had lost collars and undetected mortalities.
Certain deer may have been captured while they were occupying transi-
tional range and intensive observations may not have been made within their
respective definitive winter home ranges.. The sample included 44 deer that
were not observed in one or more winters and subsequently were either
observed or known mortalities. Two extreme cases were a male fawn and an
adult female that were marked in 1976 and first observed in 1979.

Annual survival and mortality rates were determined from numbers of known
survivors and known mortalities within individual cohorts (Tables 22 and 23) .

Those rates suggested that survival varied between individual cohorts
within a sex class.

-32-

Table 21.

Number of
is unknown

marked deer

, within yearly

samples ,

for which

the fate

Sample

Sample

Year of Last Observation

Year

Size

Never

1976

1977

1978

Total

1976

115

27

19

13

12

71

1977

69

26

11

4

41

1978

118

19

43

62

1979

109

48

48

Table 22. Annual survival and annual mortality rates of marked female

cohorts.

Cohort

% Known Survival by Year

% Known Mortality by

Year

Age at
L June 79

1976

1977

1978

1979

1976

1977

1978

1979 ]

1974

70

77

70

71

0

15

10

14

6

1975

78

83

50

25

11

8

17

0

5

1976

78

77

59

48

6

0

15

4

4

1977

—

76

71

67

—

0

4

4

3

1978

—

—

78

64

—

—

9

0

2

1979

—

—

—

61

—

—

—

9

1

Table 23. Annual survival and annual mortality rates of marked male cohorts.

Cohort

% Known Survival by Year

% Known Mortality by Year

Age at
1 June 79

1976

1977

1978

1979

1976

1977

1978

1979

1975

40

33

80

25

0

33

20

25

5

1976

77

43

50

17

5

19

40

17

4

1977

—

43

57

22

—

0

7

33

3

1978

86

35

7

6

2

1979

52

4

1

-33-

Ayerage annual survival and mortality rates also were determined by age
c ass (Tables 24, 25, and 26). Samples of marked females were sufLcient
to determine survival rates through several years. Certain inconsistencies

artifacts of pooled samples. For example,
the data indicated that fewer 2%-year-old females survived through 5
years than the number that survived through 6 years (Table 24). Also the
annual survival rate of 4+-year-old females was 64%. Yet, annual survival
rates of 74%, 73%, and 70% may be inferred from the 2, 3, and 4 year sur-
vival rates, respectively (Table 26). ^

Table 24 . Longevity of marked females by age-class.

% known

survival tc

> age-class

: %

known

Age-Class 1

2

3

4

5 6

1 2

3 4

5

6

% 73

62

40

17

6 7

14 22

1%

71

49

16

0

2

12 26

56

2%

67

33

27 40

8 18

23

10

3J5

55

26 32

11

19

26

4%

45

5

5*5

71

14

Table 25. Annual

survival

and

mortality

of marked males by age-

class .

Age-Class

*5

1*5

2*5

3*5

4*5

% known survival

67

42

36

45

25

% known mortality

4

10

36

18

25

Table 26. Annual
females

survival

and

mortality

rate

for marked 4+- year

-old

Years

1

2

3

4

% known survival

64

55

39

24

% known mortality

8

14

20

21

-34-

A computer similation model of the population (Mooney and Lonner 1978)
was developed (Table 27) for comparing simulated with observed survival
in the Swan population. The model assumed age— specific recruitment
rates (Table 16), and attempted to determine the minimum number of females,
their age-structures, and corresponding survival rates of the female
segment necessary to generate a stable population.

Table 27.

Sex and age structure
white-tailed deer.

of a simulated,

stable population

of 1,000

Age-Class

Females

Survival

Males

Survival

1

148

1.0

132

1.0

2

115

0.78

92

0.70

3

96

0.83

57

0.62

4

77

0.80

36

0.62

5

57

0.75

22

0.62

6

41

0.71

13

0.60

7

28

0.68

8

0.60

8

19

0.68

5

0.60

9

13

0.68

3

0.60

10+

34

0.65

4

0.59

The simulation followed the biological year. The simulated population
represented those animals present at the end of the year after all mortality
had occurred and immediately prior to births and aging. Within the sim-
ulation, recruitment rates were used in place of births. Because recruitment
presupposed all fawn mortality, it was necessary to assume 100% survival
for this age class.

Since the sex ratio of the adult population in the Swan Valley was unknown,
this parameter was not assumed in the simulation. Rather, male survival
was adjusted until the adult male population was also stable. The simulation
probably overestimated the population of adult males. If that were the
case, survival rates of both sexes would be less than those Indicated in the
simulation.

Preliminary estimates of population life tables were constructed from average
annual survival and mortality rates and the simulated population (Fig. 2a and
2c) . The estimate derived from simulation for both sexes was artificially
high in comparison with the estimates derived from known survival and mor-
tality because no fawn mortality was assumed in the simulation. An additional
life table was constructed for females (Fig. 2b). That curve represented
the highest possible survival that could be derived for individual age classes
from the various observed survival rates (Tables 22, 24, and 26).

Life tables derived from survival and mortality rates should have been similar.
That a large disparity between these estimates occurred was the result of un-
accounted animals in the sample. The life tables derived from simulation
represented a first approximation to the resolution of this disparity.

number number number

-35-

Figure 2. Life tables of the Swan Valley white-tailed deer population.

-36-

The life tables indicated that male mortality was higher than that of
females. The number of males declined rapidly through the first 4 years
and few males older than 5 years remained in this population. Consistent
with this conclusion, 4+-year-old males were poorly represented in the
hunting season, trapping and roadkill samples (Tables 6, 11 and 12).

Mackie, et al. (1978) indicated that male mule deer on the Armstrong range
had a life expectancy of 7-8 years and that mortality was relatively high
among fawns, light to moderate amont adults, and heavy among old males.

Female mortality rates were lower when compared to males and they were more
uniform through all age classes. The mortality pattern for females was
also similar to that of mule deer on the Armstrong range (Mackie, et al.
1978).

An important consequence of low and uniform mortality was that 5+-year-old
females comprised a substantial proportion of the population, 28% of the
females in the simulated population and 31% of those females depicted in
Figure 2b. That age-group was well represented in the hunting season, road-
kill, and trapping sample (Tables 6, 11 and 12). Distribution of that age
group was an important aspect of population dynamics. Old does evidenced
a higher recruitment rate than that of younger females (Table 16). Recruit-
ment by old does was less variable, and therefore would be somewhat pre-
dictable. Within the simulated population, 54% of the expected recruitment
would be produced by old does, while that age-group in simulated population
would produce 55% of the expected recruitment.

Mackie (1978) hypothesized in the natural population regulation of mule
deer, that high density populations occurred in complex habitats and were
characterized by low and stable annual turnover and recruitment. Those
relationships also appeared to describe the white-tailed deer population in
the Swan Valley. Observed recruitment patterns and the life table estimates
there were indicative of a stable population. They were also phenomena which
operated to maintain population stability.

Winter Distribution and Range Use

The upper Swan Valley white-tailed deer winter range extends from Goat Creek
south approximately 12 miles to Condon Creek, and from the western flood
plain of the Swan River east approximately 1.5 miles. From that boundary,
narrow extensions occur westerly into Woodward, Cedar, and Cold Creeks,
easterly into Squeezer, Lion, Pony, Dog, and Smith Creeks, and southerly
to Condon along the river. Isolated wintering areas, associated with
either the Swan River or its tributaries, also occur south of Condon.

The winter range is a mature sub-climax forest and six dominant habitat
types (H.T. ) (Pf Ister et al. 1977) occur. The Pioea/Clintonia uniflora H.T.
occurs along the bottoms of the Swan River and its tributaries, and adjacent
to potholes and marshes. This type is replaced by the Thuja pliaata/ Clint onia
uniflora H.T. on certain moist sites, especially in Squeezer Creek. The
Pseudotsuga menziesii/Symphoricarpos albus and Pseudotsuga menziesii/
Calamagrostis rubesaens H.T.s occur on warm, dry upland sites. The Abies
grandis/ Clint onia uni flora and Abies lasiooarpa/Clintonia uni flora H.T.s
occur on cool, moist upland sites.

-37-

Forested uplands are mixed communities. Douglas fir (Pseudotsuga menziesii)
in various combinations with western larch (Larix ooaidentalis) , lodgepole
pine (Pinus aontorta)’ , and ponderosa pine (Pinus ponderosa) dominate. These
species are important components of serai communities within the major
upland habitat types. Grand fir (Abies grandis) and sub-alpine fir (Abies
Zasiooarpa) are the indicated climax species on certain upland sites, but
they are poorly represented. Spruce KPioea spp.) or western red cedar
(Thuja pZioata) dominate mixed communities on raesic sites.

Fire seems to have had an important influence within the entire Swan Valley
and on the winter range. Lightening-caused fire is a normal occurence.
Evidences of previous fires included even-aged stands of lodgepole pine,
dense thickets of Douglas fir, charcoal, and scars on mature trees of
several species. Fires probably occurred often and fuels would not have
accumulated. Present pure lodgepole pine stands and Douglas fir thickets
resulted from small, hot fires. Burns, that presently are occupied by
mixed communities, were low-intensity ground fires. Fire seems to have
perpetuated the sub-climax condition more so than it initiated secondary
succession. Ground fire-suppressed regeneration of all species prevented
establishment of fire-sensitive grand fir and sub-alpine fir, and favored
f ire-resistent Douglas fir, lodgepole pine, ponderosa pine, and western
larch. Within the grand fir forests of the Swan Vahley, "A mosaic of
various aged, fire induced serai communities is the natural mode of the
vegetation" (Antos 1977:203). Singer (1975) reported that most of his
study area in the North Fork Flathead River was subjected to repeated
fires. In that area, ground fires were characteristic in Douglas fir
stands, crown fires were characteristic of other coniferous stands, and
fire was largely excluded in wet spruce stands. Arno (1976) indicated
that fires frequently occurred on the Bitterroot National Forest and that
substantial amounts of forest survived most fires.

The upland topography is an interspersion of ridges, knobs, benches, and
draws. Therefore, distinguishable areas of uniform habitat type generally
were small. Ecotones, in which more than one climax is indicated in the
overstory, understory, or both, frequently occurred. Larger areas of other-
wise uniform habitat type contained many small inclusions. Cover type and
habitat type boundaries often did not coincide, perhaps as a result of
fire. Stands of uniform habitat type often included more than one cover
type. More frequently, stands of uniform cover type included two or more
habitat types.

The winter range contained central mesic areas: the adjacent riparian zone

was ecotonal and the associated upland was a timbered mosaic. This was
a diverse habitat. Interspersion characterized the riparian and upland
communities and the relationship between these communities.

Distinct deer concentrations occurred in proximity to mesic areas. This
was evidenced by frequent observations of deer in riparian habitat. Heavily
used trails occurred in such areas and these trails followed obvious
topographic features. For example, two major trails were parallel to and
east of the Swan River through the length of the winter range. They occurred
in the floodplain near the river and at the edge between riparian and upland

-38-

habitats. Frequent bed sites, normally in the snow-wells of large trees,
were encountered near these trails. Ozoga (1968) reported that, in the
Petral Grade deeryard in northern Michigan, deer activity was closely
associated with the mature swamp conifers. That stand provided a uniform
microclimate and the most effective protection against body heat loss.

Cedar swamps also were important components of wintering areas in east
central Minnesota (Rongstad and Tester, 1969). Kearney and Gilbert (1976)
indicated that the winter distribution of white-tailed deer on the Himsworth
Game Preserve, Ontario, was related to shelter factors and that the mixed
and coniferous habitat types supported the highest deer densities.

Deer consistently used the timbered uplands in the Swan Valley but that
use was dispersed. Frequent secondary trails occurred, they originated
from major trails in riparian areas. Minor trails and tracks of individuals
radiated from the secondary trails.

Coniferous cover was an integral component of upland habitat. Similarly,
Singer (1975) indicated that white— tailed deer used areas that were stable
or intermediate with respect to fire. They used habitats modified by
ground fire in which a conifer canopy remained and small serai habitats
resulting from crown fire.

Use of clearcuts and natural openings was minor in all winters except
1977. During that mild winter, deer used clearcuts peripheral to the
normal winter distribution (Mundinger 1977). In other winters, use of
large openings was restricted either to the margins or to a single trail
with no radiating trails or tracks, that crossed the opening.

The winter range was occupied yearlong by some deer, but their summer and
winter ranges probably did not coincide. Two radio— collared does summered
within the winter range at locations other than their respective wintering
areas. Other deer move to the winter range during late November - mid-January.

Two types of movements were observed. Radio-collared does either moved
directly to their respective wintering areas or they moved to an inter-
mediate area within or peripheral to the winter range, and from thence to
their respective wintering areas. Additional movements within wintering
areas also were observed. Those appeared to be gradual reductions in the
individual's cruising radius, such that individuals occupied definitive
home ranges or areas of most confinement only in late winter-early spring.

Five radio— collar ed does were followed during three consecutive winters.

Two of those, #27-76 and #36-76 (Fig. 3), occupied intermediate areas
within the winter range throughout the 1976 and 1977 winters. In 1978
they both occupied respective intermediate ranges during early winter,
moved to definitive home ranges in midwinter, and returned to the inter-
mediate ranges prior to departing for the summer.

Deer #60-76 (Fig. 4) used an intermediate range, peripheral to the winter
range, in late fall-early winter and again each spring. She occupied the
same winter area each year. In 1977 whe used the entire 280 acres. When
confined, she used 148 acres of that area in 1976, and 119 acres in 1978.

-39-

/(\\\\\

, v\\\\\

Kwwm
iC\\\\\\\

U\\\\\\\

, vWWWWX

>\\\\\A

?\\\\\N,

i\\\\W\

K\\\\w\

<\\\\\\\

, v\\\\W\\
.^WWWNM

l\\>\\\\W\n

'^>\\\\\\\

vN'sW'',
L\\\\\\
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1976 and 1977 Home Range
\vs 1978 Home Range
Intensive Use
Marsh

SCALE

IMile

Figure 3. Winter home range of deer 36-76.

Deer #4-76 (Fig. 5) did not use an intermediate range and occupied the
same winter area each year. She used the entire 230 acres in 1977. That
area included two different confinement areas, 156 and 47 acres, which were
used in 1976 and 1978, respectively.

Deer #25-77 (Fig. 6) occupied a 115-acre winter home range during 1977.
Subsequently, that area was not used in any season. In 1978 and 1979 she
occupied a 95-acre area that was near, but distinct from her 1977 winter
home range. Her summer range was less than 2 miles downriver from her
difinitlve winter range. In 1978 and 1979 her return movements were
gradual .

Ten radio-collared does were followed during two consecutive winters. Deer
#4-77 was a 1976-77 fawn of #4-76. Her 1978 and 1979 home ranges were
similar to the 1978 and 1976 home ranges, respectively, of deer #4-76 (Fig. 5).

-AO-

Figure A.

Winter home range of deer 60-76.

,1

-41-

s\\'

1976 Home Range

1977 Home Range

1978 Home Range
Intensive Use

Figure 5. Winter home range of deer 4-76.

-42-

Flgure 6

Winter home range of deer 25-11 .

-43-

Deer //50 75 wintered near Goat Creek and was Monitored in 1976 and 1977.

Those years her winter ranges were similar to those of deer //60-76 (Fig! 4).

Deer #23-77 wintered along Pony Creek. She used similar areas, approximately
128 acres, in 1977 and 1978.

Deer #56-77 wintered along Alder Creek in 1977 and near Squeezer Creek in
1978. The Alder Creek location was peripheral to the winter range. She
used this as an intermediate range in spring and fall 1977 and spring 1978.

Deer #39-78 wintered near Cedar Creek in 1978. In spring 1978 she used
an intermediate range near Simmons Meadow. She returned to Simmons Meadow
in fall 1978 and remained there for the 1979 winter.

Deer #41-78 wintered near the confluence of Goat and Squeezer Creeks in
1973 and 1979. She used an intermediate area along Goat Creek in Spring
1978 and 1979. In fall 1978 she first returned to that intermediate range,
then gradually moved down Goat Creek and occupied her definitive winter
range by mid-February.

Deer #48-78 (Fig. 7) apparently used two winter home ranges in 1978
and 1979. Through February in both years, whe was found either near the
confluence of Goat Creek with the Swan River or near a large pothole that
flowed into Simmons Creek. She used the pothole area more consistently
in late winter through early spring.

Deer #56-78 (Fig. 8) wintered along Dog Creek in 1978 and 1979. Her 1979
winter home range overlapped only a portion of that area used in 1978.

She used an active timber sale in 1978. That area attracted an unusual
concentration of deer in 1978, compared with deer use in 1976 and 1977,
while few deer used that area in 1979.

Deer #26-78 used similar winter home ranges in Cedar Creek in 1978 and
V1979. Deer #63-78 also used similar winter home ranges along Pony Creek in
both years.

A consistent range use pattern was apparent for all radio-collard does.
Definitive winter home ranges were less than 160 acres. Each deer used an
activity center (s) within riparian habitat. The activity center was a
comparatively small portion of the home range, yet each deer spent most
of its time there. Gladfelter (1978) reported that white-tailed deer in
Iowa used winter home ranges of 100-370 acres and that activity centers
comprised less than 15% of the home range. Rongstad and Tester (1969)
reported winter home ranges of 400-1,200 acres and indicated that deer
concentrated their use in a small portion of their home range.

Each deer also used additional riparian habitat and a comparatively large
area of upland habitat accessible from the riparian area. Riparian areas
were used for resting and security; uplands were used for foraging. As
winter progressed, the cruising radius of each deer gradually was reduced,
that occurred as a reduction in the amount of upland area used. This
phenomenon was not observed during the mild 1977 winter. Rongstad and Tester

' 1978*79 Home Range
Activity Center
i: Marsh

1978 Home Range

1979 Home Range
Activity Center
Marsh

Figure 8. Winter home range of deer 56-78

-45-

(1969) reported that with increased snow depths, deer remained in the
cedar swamps, upland foraging stopped, and home ranges decreased. Drolet
(1976) reported an inverse relationship between home range size and snow
depth.

Loveless (1967) suggested that mule deer move about within their winter
habitat to seek the most comfortable temperature zones. Ozoga (1968)
demonstrated microclimatic variation within the Petral Grade deeryard.

In that area, mature swamp conifers provided the warmest average temperatures,
the most stable microclimate, and snow conditions were the most amenable
to travel. Moen (1968) demonstrated that under clear night skies, deer
experienced greater radiant heat loss in an open field than under a cedar
canopy. Drolet (1976) indicated that a dense forest of conifers and mixed
woods provided more protection against adverse weather than open mixed
and hardwood forest. Presumably, timbered riparian areas in the Swan
Valley provided the most comfortable microclimate.

Animals which wintered in the upper Swan Valley and at Salmon Lake were
different herd units within the same overall population. Apparently deer in
this population were capable of seeking out ameliorating microclimates in
physiographically dissimilar situations. The Salmon Lake winter range has
greater topographic relief than the Swan Valley and is typified by open
canopy forest habitat types within the Pinus pondevosa and Pseudotsuga
menziesii series. High deer use occurred on ridges and slopes that were
first to be free of snow. Those areas also provided sites for sunning
(Janke 1977).

Food Habits

White-tailed deer food habits were determined by rumen analysis. Analysis
of fall and winter samples, 1976-78 was presented previously (Mundinger 1978).
Analysis of the 1979 sample has not been completed.

Deciduous browse was the predominant item in fall rumen samples. Oregon
grape (Berberis repens) was the single most Important species. Service-
berry (Amelanahier alnifolia) and snowberry (Symphorioapos albus) were also
important. Use of conifer browse was minor in fall. Greater use of forbs
occurred in fall as compared with winter and spring samples. Bunchberry
dogwood (Cornns canadensis) and twin-flower (Linnaea boratis) were important
forbs.

Deciduous browse was the predominant item during winter 1976 and 1977,

Oregon grape was the major species. A variety of species, notably service-
berry, kinikinnik (Aratostaphylos uva-usi) , evergreen ceanothus (Ceanothus
oaZutinus), and willow (Salix spp.), received minor use. Use of conifers,
particularly Douglas fir and common juniper (Juniperis communis) , increased
relative to fall use. Conifers predominated in the winter 1978 diet.

Douglas fir was the most Important species. Common juniper, spruce and
lodgepole pine were used consistently that winter. Tree-moss (Allectoria spp.)
probably was important every winter, but its importance was difficult to
determine by rumen analysis.

Deciduous browse again predominated in the spring diet. The greatest
use of Oregon grape occurred in that season. Other important deciduous

-46-

species included serviceberry , kinikinnik, and Myrtle pachistima (Paohistima
mypsinites ) . Common juniper and Douglas fir were important conifers, but
the use of conifers decreased in the spring diet, as compared to use dur-
ing winter. The use of forbs increased, relative to the winter diet, but
forbs were less important than in the fall. Twin-flower and bear grass
(Xerophyllum tenax) were the prominant species.

Winter food habits during 1976-78 generally were consistent with those
reported for 1957 (Weckwerth 1958) and 1970 (Hildebrand 1971). Species
composition in the diet was similar, except for thelact of snowbrush
ceanothus in the 1957 samples. A greater percentage of Oregon grape
occurred in the 1976 and 1977 samples than in those from 1957 and 1970.
Bergeson (1943) Indicated that the majority of food consumed was Douglas
fir and tree-moss. Use of willow, mountain maple (Aoev gZabvwn) , service-
berry, ceanothus {Ceanothus sp.), and common juniper was also indicated.
Oregon grape, huckleberry (Vacoinium spp.), and kinikinnik also were
used furing periods of reduced snow cover. Present data were consist -,nt
with these observations.

White-tailed deer winter food habits generally were similar to those re-
ported for the Fisher River-Wolf Creek winter range (Firebaugh 1970; Flath
1971, 1972). In both areas, Oregon grape and Douglas fir were prominant
items and the use of Douglas fir increased with decreasing availability
(due to snow) of Oregon grape. A variety of deciduous species was used as
minor items.

Grasses were the predominant item in the winter diet of white-tailed deer
at Salmon Lake (Janke 1977). Oregon grape and Douglas fir were consistently
used, but in lesser quantities than in either the Swan or the Fisher
River-Wolf Creek areas. Serviceberry was used to a greater extent at
Salmon Lake.

Movements

Nine radio-equipped deer were followed in 1976. Nine deer, four of
which were included in the 1976 sample, were followed in 1977. The 1978
sample included 19 deer, of which four were in the 1976 sample and three
were in the 1977 sample. During 1979, 17 deer were followed. This
was comprised of 1 deer from the 1977 sample, 7 from the 1978 sample, and
9 deer which were collared in 1979. Distributional histories of deer
radioed in 1976, 1977 and 1978 were described by Mundinger (1978). Move-
ments through the summer of 1979 are summarized in Figures 9-15.

Among deer equipped with transmitters in 1979, deer #93-78 (deer a in Fig. 16)
was captured, as a fawn, in Dog Creek in February 1978. She was recaptured
and equipped with a radio in February 1979. She remained in Dog Creek
through early April. Thereafter, she occupied her summer range near the
Swan River, approximately 11 miles south of Dog Creek.

Deer #37-79 (deer b in Fig. 16), a 2%-year-old female, was captured in
Dog Creek in early February 1979. She remained in Dog Creek through early
April, had moved to McKay Creek by late April and to Lindbergh Lake by
late May. She then summered at Lindbergh Lake approximately 15 miles south
of her wintering area.

-47-

Figure 9. Movements of deer 4-76
relocations.

as determined from 1976, 1977 and 1978

-48

Figure 10. Movements of deer 27-76, as determined from 1976, 1977, and
1978 relocations.

•49

Figure 11. Movements of deer 36-76, as determined from 1976, 1977, and 19
relocations.

-50-

Figure 12. Movements of deer 60-76, as determined from 1976 and 1977
relocations.

-51

■52

Figure 1'^* Movements of 5 radio-equipped deer during 1977

-53-

Figure 15. Movements of 11 radio-equipped deer during 1978

Figure 16. Movements of 8 radio-equipped deer during 1979

-55-

Deer #55-79, (deer c in Fig. 16), a 3%-year-old female, was captured
in Lion Creek in mid-February. She remained in the vicinity of her
wintering area through mid-April. She occupied her summer range, in the
North Fork of Rumble Creek by late April. Fourteen miles separated her
winter and summer ranges.

Deer #74-79 (deer d in Fig. 16), a 3%-year-old female, was captured in
Lion Creek in late February. She remained in Lion Creek through mid-April,
moved to Rainy Lake in late April, and occupied her summer range in Rich-
mond Creek by early May. She moved approximately 25 miles.

Deer #79-79 (deer e in Fig. 16), a ZS^-year-old female, was captured in

Cedar Creek in late February. She remained in Cedar Creek through March,

then occupied an intermediate range approximately 3 miles east in Squeezer
Creek. She occupied her summering area, approximately 23 miles south of
Cedar Creek, by mid-May. She apparently used two summer activity centers.
One was north of Lindbergh Lake and the other in Glacier Sloughs, 1.5
miles northwest of the first.

Deer #87-79 (deer f in Fig. 16), a yearling female, was captured in Dog
Creek in late February. She remained there through early April and then
moved three miles south to Smith Creek for the summer.

Deer #91-79 (deer g in Fig. 16), a 3%— year-old female, was captured in

Dog Creek in early March. During March and April, she was found either near
the trap site or in Condon Creek, 1.5 miles southeast. Sheleft the winter
range in late April and occupied her summer range in Kraft Creek in early
May. Eleven miles separated her winter and summer areas. During May-raid-
June, she cruised between Kraft, Hemlock and Windfall Creeks, an area larger
than one square mile. By late June, she was settled in Kraft Creek.

Deer #103-79 (deer h in Fig. 16), a 2J2-year— old female, was captured in
Goat Creek in early March. She remained in Goat Creek through early May.

In mid-May, she was found once in Buck Creek. Thereafter, she occupied her
summer range near Summit Lake, approximately 28 miles south of Goat Creek.

Deer #102-79, a 2Js-year-old female, was captured in Lion Creek in early
March. She remained there through April. An Indefinite location in lower
Glacier Creek was obtained in early May. Thereafter, the transmitter
failed .

Each radio-collared deer used recognizable summer and winter ranges, and
each was faithful to those areas. Certain deer also occupied distinguishable
intermediate ranges during spring, and in several instances, the inter-
mediate ranges were occupied again in the fall. Other deer apparently were
able to satisfy their spring and fall range requirements within their
winter and summer home ranges. Deer moved directly between seasonal ranges

or between seasonal and Intermediate ranges. Rongstad and Tester (1969)
also observed direct movements from winter to summer ranges.

The average straight-line distance between winter and summer home ranges
was 19 miles (s.e.=.32), and ranged from 3-44 miles. Gladfelter (1978)
reported average movements of 14 miles and a range of 0-44 miles.

-56-

Mass migration did not occur. Rather, white-tailed deer behaved as in-
dividuals in their movements. Deer which wintered in close proximity
often summered in distinctly different areas, and the converse also was
true. The timing of movements occurred as individual events, such that
certain deer left the winter range at the onset of spring, while others
remained longer. Deer also were consistent in this behavior. Mackxe and
Knowles (1977) indicated that mule deer in the Bridger Mountains moved as
Individuals between seasonal ranges.

Summer Distribution and Range Use

White-tailed deer summered throughout the Swan Valley at low to mid-
elevations. The majority of deer that wintered in the upper Swan summered
between Condon and the Swan-Clearwater divide, south of the winter range.
Movements of marked deer indicated that lesser numbers summered in the
Clearwater River drainage. Summer distribution overlaped that of deer
which disperse from the Salmon Lake Winter Range (Janke 1977).

Deer also summered north of the winter range, between Goat Creek and Swan
Lake. A few summer observations of collared deer have been reported in
that area, but specific collars were not identified. Presumably, the
Goat Creek-Swan Lake summer population included a few deer that wintered in
the upper Swan and the majority wintered in the lower Swan. The population
appeared to be contiguous from Salmon Lake to Echo Lake, with three or
more recognizable sub-populations. This hypothesis should be tested with
additional marked animals from the three winter ranges.

Similarities were evident in the summer range-use patterns of radio-equipped
deer. Summer home ranges occurred in closed-canopy forest. A variety of
habitat types, within the Pseudotsuga menziesiii Abies grandis ^ and Abies
tasioaarpa series, occurred. They were represented either by mixed, serai
communities or dense stands of lodgepole pine. Habitat and cover types
were not consistent between home ranges. Those paramenters probably were
less important than mere presence of dense coniferous cover in serai
communities.

Each radio-collared deer used a small activity center that was near a
meslc sit. The sites occurred as creek bottoms, marshy creek bottoms,
potholes, marshes, and meadows. Habitat types, within the Pioea series,
often occurred in the mesic margins and spruce, in combination with other
conifers, dominated.

Certain summer home ranges also included recent clearcuts. The heaviest
use apparently was confined to the edges, as few tracks or pellets were
encountered elsewhere in clearcuts. Natural openings and wet sites,
which had been isolated by logging, were not used.

Evidences of fire were frequently enountered. Fire seems to have had an
Influence similar to that described for the winter range. However, hot fires
may have been more extensive. Stands of dense lodgepole pine, particularly
along Glacier Creek, presently occupy these sites.

-57-

Habitat diversity also characterized summer home ranges. Mesic sites
were intersperced with uplands. Uplands were mosaics of habitat and
cover types. The mosaics resulted from topographic variations and
previous influences of fire. Only major trails were recognizable on
summer range. They always followed edges.

The distribution of radio-collared deer and hunter tag returns (Figs. 17,

18 and 19) suggested the occurrence of three important summering areas.
Densest summer concentrations apparently occurred in the southwest
quadrant of the valley, from Glacier Creek south to the Swan-Clearwater
divide and from the Swan River west to the base of the Mission Mountains.

The area included the summer home ranges of 15 of 34 radio-collared deer.
Seven of 24 hunter-returned collars were recovered in that area. A
disproportionate percentage of the deer harvest, relative to hunting
pressure, occurred south of Elk Creek (Table 2) , The southwestern portion
of the Swan Valley was typified by 1) a high density of small meadows and
potholes, 2) numerous small creeks, 3) topographic variation and 4) ex-
tensive, mature forest. Several extensive fires probably occurred in this
area during the past century.

Another important summer concentration apparently occurred immediately
north of Glacier Creek, between Elk and Jim Creeks. The area included
summering areas of 5 radio-collared deer and 4 tag-returns. It is
physiographlcally similar to Glacier Creek although recent logging has
been extensive. The radio-collared deer were associated with remaining
stands of mature timber. The Elk-Jim Creek area could probably support
more summering deer, but adequate cover is lacking.

Four tag returns and two radio-collared deer were associated with the
southeastern quadrant of the valley, between Barber and Owl Creeks. That
area is drier than the western half of the drainage. Large clearcuts occur
in portions of it, but fewer mesic areas have been isolated by logging,
in comparison with Elk-Jim Creek.

Timber Management

Timber production is the dominant land use in the Swan Valley. The influence
of timber management on white-tailed deer may be inferred from the previous
discussions of deer distribution and habitat relationships. Deer occupy
small seasonal home ranges, which are mosaics of essential habitat components,
mesic sites and mature, subclimax forest.

Fire suppression, one aspect of timber management, has had a subtle influence
on white-tailed deer habitat. Fire seems to have had a stabilizing in-
fluence on plant succession, especially on winter range. The result was a
subclimax condition and a predictable combination of forage and cover. In the
absence of fire, plant succession has progressed and the forage resource
probably has decreased.

Previous timber harvests have reduced the total area of white-tailed deer
habitat. This has occurred because cover was removed, habitat integrity
and diversity were disrupted, and logging units werelarge in comparison with
average home range size. Specific examples of detrimental practices
included: (1) logging units defined by property lines rather than eco-

logical boundaries, such that a uniform prescription included a diversity of

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Figure 17. Recovery locations of 5 observation-collared deer during the
1976 hunting season.

-59-

a 21/2 Female
b 2 1/2 Male
c 3 1/2 Female
d 2 1/2 Male
e 3 1/2 Male
f 2 1/2 Male

9 8 1/2 Female
h 3 1/2 Female
k 2 1/2 Male
n 1 l/2Male
o 1 1/2 Female

Figure 18. Recovery locations of 11 observation-collared deer during the
1977 hunting season.

60-

Figure 19. Recovery locations of 8 observation-collared deer during the
1978 hunting season.

-61-

of habitat/cover types; (2) logging units which isolated important topo-
graphic features, eg. mesic sites, ridge and draw complexes; and (3) large
clearcuts on winter range.

Logging has impacted extensive areas in the Swan Valley. Benefits which
may have resulted from that logging will not appear for deer until cover
develops. Regeneration is proceeding slowly. It is doubtful that logging
can be used effectively to improve white-tailed deer habitat until recent
cuts are reoccupied by deer. Rather, logging in the next 20-50 years
should be designed to minimize detrimental influences within presently
occupied deer range.

The integrity of mesic sites with associated cover must be maintained on
summer range. Mesic sites must also be contiguous with larger units of
cover. Wlthdrawel from treatment is preferred. Logging in riparian areas
may be acceptable if it is restricted to a very light selection for san-
itation/ salvage.

A variety of logging techniques may be appropriate on summer range uplands.

The primary considerations are that unit boundaries should follow ecological
boundaries and clearcuts should be less than 20 acres.

The integrity of both riparian areas and upland foraging areas is essential
to the winter range. Riparian areas should be withdrawn from treatment,
although very light selection may be tolerable.

Winter range uplands should be managed to encourage communities with mixed
species in multiple age classes. Logging should employ selection/group
selection within units of less than 20 acres or clearcuts of less than 5
acres. Units should be contained within a natural boundary. Selection
should not reduce the overstory below 70% crox^n closure.

On all seasonal ranges, sale proposals should be evaluated on an individual
basis. Additional modifications may be necessary to accommodate previous
logging.

Logging constraints for white-tail deer should be compatable with the
habitat requirements of elk. The reverse may not be true. Therefore,
considerations for deer should have precedence where the species are sympatric.

These recommendations are extrapolations from observed deer range use pat-
terns. Field tests should be conducted prior to broad application. During
the interim, the recommendations are a reasonable alternative to obviously
detrimental practices.

LITERATURE CITED

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Forest. U.S.D.A. Forest Service. Res. Paper INT-187. 29 p.

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Bergeson, W. R. 1943. Swan Valley deer study. Unpub. Mont. Dept. Fish
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D.C.

Singer, F. J. 1975. Wildfire and ungulates in the Glacier National Park area,
northwestern Montana. Unpub. M.S. Thesis. Univ. Idaho, Moscow. 53 p.

Verme, L. J. 1962. Mortality of white-tailed deer fawns in relation to
nutrution. P. 15-38 lai Proc. Natol. White-tailed Deer Disease Symp.,

I. Univ. Georgia, Athens.

• 1967. Influence of experimental diets on white-tailed deer repro-
duction. Trans. N.A. Wildl. Conf. 32:405-420.

_. 1969. Reproductive patterns of white-tailed deer related to nutri-

tional plane. J. Wildl. Manage. 33:881-887.

-65-

. 1977. Assessment of natal mortality in upper Michigan deer. J.

Wildl. Manage. 41:700-708.

Weckwerth, R. 1958. Big game surveys and investigations - Swan Unit.

Job Prog. Kept., Mont. Dept. Fish and Game, Fed. Aid Proj . W-71-R-3.

21 p.

Wilkins, B. T. 1957. Range use, food habits, and agricultural relation-
ships of the mule deer, Bridger Mountains, Montana. J. Wildl. Manage.
21:159-169.

Submitted by:

John G. Mundinger

-67-

JOB TITLE: White-tailed deer movements, survival and population

characteristics in the Clearwater River drainage, Montana.

ABSTRACT: A study of white-tailed deer, initiated in the Clearwater

River drainage during 1975, was continued during winter-
summer 1978 and 1979. Findings are being prepared in the
final report.

OBJECTIVES:

To determine and describe:

1. Summer distribution of white-tailed deer which winter in the Salmon
Lake area of the Clearwater drainage.

2. The status, i.e., numbers and trend, fawn production and survival,
and mortality factors affecting this deer population.

3. Seasonal food habits.

A. Winter range condition.

5. The potential effects of logging on deer habitats and population
in the Clearwater River drainage.

FINDINGS:

Field work continued through the winter-summer 1979 and data have been
compiled. Data analyses and the final job report will be completed in
December 1980.

Submitted by:

Barbara Slott

-69-

Job Title’ Population ecology and habitat ralationships of

mule deer in the Bridger Mountains, Montana.

ABSTRACT

This report describes studies on the population ecology and habitat relation-
ships of mule deer in the Bridger Mountains, Montana, with emphasis on
population studies of mule deer associated within the Armstrong winter
range from 1971-72 through 1979. Winter distributions were generally
similar to previous years although significantly higher concentrations
of deer used the West Slope-South Unit in the mouth of Bridger Canyon;
and significantly fewer numbers used the Blacktail Mountain Winter Range.
Distributional data on 30 deer radio-collared during 1975-79 on the Armstrong
winter range indicated that 50% summered in Bill Smith and North Cottonwood
Canyon, 23% in the Frazier, Carol and Flathead drainages east of the
Bridger Divide, 20% in Mill, Johnson and Pass Creeks and 7% in Tom Reese
Creek. Generalized dispersal patterns of marked deer off the Armstrong,
Schafer and Brackett Creek winter ranges suggested that mule deer associated
with individual winter ranges may comprise population units that occupy
rather distinct yearlong herd ranges. Individual marked deer that use
particular portions of the Armstrong winter range were shown to be at least
generally associated with particular portions of the summer herd range.
Population data for the Armstrong winter range indicated that about 234
mule deer were present in early winter; the number decreasing to about 140
animals in early spring. Overwinter mortality, during the severe winter,
resulted in an estimated loss of 80% of the fawns, 24% of adult males,
and 5% of adult females present in early winter. The sex ratio of 14
marked fawns that survived the winter was 180 males :100 females. Fawn
mortality was unevenly distributed on the winter range with 79% and 44%
apparently dying on the north and central winter range subunits, respectively.
The observed fawn:female ratio in early winter was 93:100, the highest
recorded since the study began in 1971-72. However, by May the ratio
decreased to an estimated 18 fawn: 100 does, which was lower than previous
years except 1975 and 1976. The proportion of adult males in the Armstrong
population increased slightly since spring 1978 as a result of some improve-
ment in yearling recruitment. Approximately 83% of 17 marked does were
2% years of age or less. Proportions of adult females declined in 1978-79
after remaining relatively stable from 1975-78. Approximately 68% of 82
marked females were bh years or older, while only 4% were yearlings. Totals
of 4,854 and 4,594 mule deer were counted on winter ranges, including the
North 16-Mile area, during early and late winter, respectively. Calculations
based on numbers observed within the Bridger complex and helicopter sampling
efficiencies of 40% for west slope ranges and 48% for east slope and the
South 16-Mlle area suggested that as many as 7,800 mule deer may have been
present in early winter (December 1978). The estimate for mid-March, based
on sampling efficiencies of 64-65%, was approximately 5,500 mule deer.

Total mortality for the late— December mid— March period was indicated at about
29%, including 10-12% of the adults and 56-58% of all fawns. These rates as
well as the late winter population estimate did not include additional
mortality which accrued in late March and April on many, if not most Bridger
Mountain winter ranges.

-70-

Job TitlG Population ecology and habitat relationships of mule

deer in the Bridger Mountains, Montana.

Job ObjGCtive To determine the environmental requirements of mule deer

and factors regulating mule deer populations in mountain-
foothill habitats of southwestern Montana.

To determine the effects of various potentially
competing land use and management practices upon mule
deer in southwestern Montana.

To develop new and improved guidelines for management
of southwestern Montana mule deer populations and their
habitats.

INTRODUCTION

This report describes and summarizes findings of studies on the
population ecology and habitat relationships of mule deer in the Bridger
Mountains, Montana, for the period 1 July 1978 through 30 July 1979.

These studies were initiated and have been conducted continuously since
the winter of 1971-72 following two, broadly different approaches:

(1) Intensive studies of the distribution, movements, range use and pop-
ulation characteristics of mule deer associated with specific winter
ranges and (2) Extensive studies of the seasonal distribution, habitat
relations and population characteristics of mule deer generally throughout
the Bridger Mountain complex. The history and general nature of both
efforts were described by Mackie et al. (1978).

In this report, emphasis is given to information obtained for mule deer
associated with the primary study area, the Armstrong range; though data
obtained generally and for other populations are included or presented
comparatively where appropriate. Findings from several special, intensive
studies on local areas are or will be reported separately as progress re-
ports (Rosgaard 1979) or supplementary final thesis reports (Steerey
1979, Youmans 1979, Nyberg in prep.)

ACKNOWLEDGEMENTS

Studies of mule deer in the Bridger Mountains have been conducted with
the cooperation and assistance of the Montana Department of Fish and Game,
Region 3, and the U. S. Forest Service, Gallatin National Forest and Bozeman
Ranger District. The willingness of numerous private landowners throughout
the Bridger Range to allow access to their lands and in many cases their
direct assistance in various aspects of the studies has been a major factor
both in enabling the work to be done and in results achieved. Murray Duffy,
Central Helicopters, Bozeman, and James Stradley, Gallatin Flying Service,
Belgrade, both contributed extensively through their flying and observational
skills in helicopter and fixed wing aerial surveys, respectively. Much credit
is also due to all of the many individual Montana Department of Fish and Game
personnel and Montana State University graduate and undergraduate students
who have participated in one way or another in the studies, and without whose
help much of the work could never have been accomplished.

-71-

THE STUDY AREA

The Bridger Mountain Range (Fig. 1) is located in northeastern
Gallatin and northwestern Park Counties, Montana. The total study area,
encompassing the Bridger Range complex and adjacent foothills, prairie
and agricultural lands used by or available to deer, includes a land area
of approximately 800 square miles. It is bounded on the west by the East
Gallatin River, Dry Creek and the Dry Creek-Maudlow road; on the north by
16-Mile Creek, its Middle Fork, and Cottonwood Creek; on the east by
U. S. Highway 89 and the Shields River; and on the south by the Yellowstone
River and Interstate Highway 90 between Livingston and Bozeman. A portion
of the 16-Mile Creek winter range extends north of this boundary to the
Gallat in-Meagher County line. Whether deer associated with that north
portion of the 16-Mlle winter range move south from the Big Belt Mountains
or include some animals from the Bridger complex is not known at this time.

The Bridger Mountain complex includes the main Bridger Range which extends
north and west in a gently curving arc from Bridger Canyon to Blacktail
Mountain, a distance of about 23 miles (McMannis 1955). It also includes
Elkhorn Ridge, which extends northeast off the northern portion of the main
range, and Battle and Bangtail Ridges, which extend northeast and southeast,
respectively, from about the center of the range. Topographic and geological
features of the Bridger Range have been described by McMannis (1955).
Elevations on the study area range from about 4,600 ft. along 16-Mile Creek
in the northwestern corner of the area to 9,665 ft. Highest elevation and
the most severe and complex topography occur along the main Bridger Range;
while easterly extending ridges and drainages are of lower (less than 7,600
ft.) and less severe relief.

Seven, generally distinct, major mule deer winter ranges occur around the
perimeter of the Bridger Range (Fig. 1). Collectively, these occupy an
area of about 90,000 acres (140 ml2) or slightly less than 20% of the total
area available to deer within the Bridger complex.

Three of the major winter ranges occur on the west slope along a narrow
band of steep, south and west facing slopes which extend in elevation from
5,200-5,600 ft at their lower limit up to 6,800-7,200 ft. The South unit,
which Includes the Schafer Creek winter range as a sub-unit, extends from’
the mouth of Bridger Canyon north to Ross Creek and encompasses a total
maximum area of about 9 mi2. The North unit. Including the very intensively
studied Armstrong winter range as a subunit, spans a maximum area of
approximately 5 mi^ from Ross Creek north to Pass Creek. The Blacktail
Mountain winter range, from Pass Creek north to Blacktail Creek, comprises
about 3.6 mi2.

The South 16-Mile winter range is located at the extreme north end of the
main Bridger Range and comprises all of the area south of 16-Mile Creek
and its Middle Fork, including Table Mountain, the lower South Fork and
the south to westerly facing slopes of Hatfield Mountain. It includes a
total area of approximately 37.8 mi2 within an elevational range of from
4,600 ft along 16-Mile Creek to about 6,000 ft. The terrain is generally
of the "Breaks" type of slight to moderate gradient.

-72-

Figure 1.

Map of the Bridget Range showing major features and the
location of primary study areas.

-73-

The three major winter ranges which occur along the east side of the Bridget
Range are broad, open ridge and bench lands which extend from the lower
slopes of Battle and Bangtail Ridges to the Shields and/or Yellowstone Rivers.
Elevations range from 4,800-5,200 ft. at the lower limits of mule deer distri-
bution to 6,000-6,200 at the upper limit for most years. The Battle Ridge
winter range includes about 27.5 mi?^ the east-central portion of which,
between Antelope and Fox Creeks, receives only light usage by mule deer.
Because of this, future studies may determine that two separate winter ranges
should be recognized; one extending from Horse Creek to Fox Creek, the other
from approximately the Looking Glass-Antelope Creek divide north to Flathead
Creek. The Brackett Creek winter range encompasses about 38.5 mi?, including
the Brackett Creek drainage below Miles Creek and all but the upper reaches of
Canyon Creek and Bangtail Creek. The Livingston area includes about 28.9 mi^

extending from the north rim of Ferry Cr. south and west to Billman and Flynn
Creeks.

The major winter ranges differ broadly in vegetal, climatic and land use
characteristics as well as in their topo-physiographic attributes. In gen-
eral, the east side ranges are characterized by relatively open vegetation
consisting of sagebrush-grassland with scattered clumps or individual plants
of Rocky Mountain juniper (Juniperus saopulorum) . Agricultural croplands
are interspersed, especially at lower limits, while timber cover occurs
mainly along a few drainages and at the upper margins. The 16-Mile basin
area is characterized by extensive stands of shrubby and shrub-grass vege-
tation interspersed by open to moderately dense stands of Douglas fir
(Pseudotsuga menziesi-i) , limber pine (Pinus ftexi-lis) , and Rocky Mountain
juniper along slopes of all drainageways . West slope ranges are generally
characterized by steep open slopes dominated by grass-forb or grass-shrub
vegetation. Moderate to dense stands of timber, primarily Douglas fir, are
interspersed; extending upward along north slopes of canyons and draws from
the lower limits of the winter range. Open stands of timber and Rocky
Mountain juniper usually extend onto south and westerly exposures at higher
elevations. Major differences between west slope ranges appear to be in
the relative representation of various habitat and cover types and in the
occurrence of some individual plant species of importance to deer. For
example, antelope bitterbrush (Purshia tridentata) is well represented in
shrub-grass vegetation on the Armstrong range but absent on the Schafer
Creek area (Steerey 1977).

To date, our studies have centered on the Armstrong winter range and adjacent
spring-summer-fall ranges used by deer associated with that area, which
includes primarily that portion of the main Bridget Range extending from
Flathead Pass south to Ross Pass. Vegetational and other "habitat" and
environmental characteristics of much of this area have been described in
detail by Bucsis (1974) and Pac (1976). Steerey (1979) has described
vegatatlonal attributes of yearlong ranges used by mule deer associated with
the Schafer Creek winter range, located along the west slope from approxi-
mately Ross Creek south to Middle Cottonwood Creek. Studies to provide
similar information for portions of the Bridger Mountain complex used by
deer associated with the Brackett Creek winter range, located along the
east slope from approximately Brackett Creek south to Bangtail Creek, are
being completed by Nyberg (in prep.) and Rosgaard (1979). Results of current
studies to generally define vegetational and other environmental character-
istics of the Bridger Range as a whole are presented elsewhere in this
report .

-74-

METHODS

Habitat Studies

Habitat parameters measured and/or monitored and general methodology employed
were described by Mackie et al. (1978:91-93); though some modifications were
necessary. Nutritional analysis of forage plant samples collected during
the summer of 1978 included only crude protein and moisture contents. Small
samples and high analytical cost precluded determination of total energy
content. Because of cost considerations, it now seems unlikely that complete
nutritional characterization of the forage base in various vegetation types
can be achieved. Also, it may not be possible to complete measurements of
dry matter forage production in the major habitat types due to the lack of
manpower and funding necessary to carry out the large amount of work involved.
One additional modification, also due to reduced funding, was the estab-
lishment of only one, rather than two weather stations on the Armstrong
winter range.

During 1978-79, emphasis was placed on (1) obtaining basic weather data for
five of the major mule deer winter ranges to: (a) document prevailing con-

ditions and (b) to compare conditions between winter ranges and between
representative winter ranges and the nearest office of U.S. Weather Service
Stations; (2) continuing vegatation cover and habitat type delineations and
mapping of major mule deer summer ranges; and (3) collection and analysis
of nutritional values of forage plant samples from various habitat types and
elevations within the range of the Armstrong deer herd.

Population Studies

Mule deer winter distributions and population and range use characteristics
were determined primarily through aerial surveys during early and late
winter. For the Armstrong range, population data were also obtained through
ground observations associated with deer trapping and other studies through-
out the winter as well as specific observations of marked and unmarked deer
on the area during late winter and early spring.

The intensive helicopter surveys, employing a Bell 47G 3B-2 helicopter with
the same pilot and observer as previous years, were completed December 26-31,
1978 and March 12-14, 1979. All major mule deer wintering areas in the
Bridget complex were covered during both early and late winter surveys.
Locations, numbers, sex (in early winter) and age (adult or fawn) were
recorded. In addition, elevations and habitat types used, as well as num-
bers, locations and identifying markings of collared deer were noted.

Similar records for all deer observed during fixed wing aerial surveys to
relocate "radio"-collared deer at approximately weekly intervals through-
out the year provided supplementary population data.

Ground observations to develop late winter population estimates were
recorded during a total of 12 days in April. All mule deer observed were
recorded as to number, age (adult and fawn), whether marked, specific
markings, activity, location, habitat types, elevation, slope gradient and
exposure. Groups were recorded' collectively, with locations marked precisely
on aerial photograph-habitat type maps.

-75 -

Additional marked deer in the Armstrong population were obtained by trapping
between 7 January and 6 March. Trapping methods included a corral type bait
trap and cannon net as described by Mackie et al. (1975) plus portable bait
traps (Clover 1954). A total of 250 mule deer (109 different animals) was
trapped, including 141 recaptures of 37 previously marked animals and 71
new (Table 1). General markers were four-inch wide collars or neckbands
of Armor-tite fabric, color coded using Tuff-flex marking paint, and fastened
with blind rivets. Radio-transmitter collars were fastened to five new deer,
two males and three females (Appendix Table 20). Three other females, two
wearing non-functioning transmitters and the other a neckband, were recap-
tured and ecjuipped with new transmitter collars. At the conclusion of the
1979 trapping period, a total of 15 deer held functional transmitters. In
April, a transmitter in operation since January 1978 failed. In May, an
adult male, 8+-years of age, wearing a transmitter collar attached in Febru-
ary, was found dead. A third transmitter, in operation on a doe since
January 1978, apparently failed in August. A summary of all mule deer
tagged on the area from 1972 through 1979 and their status as of June 1979
is given in Tables 1 , 2 and 3.

Table 1. Summary of mule deer trapping effort and success on the Armstrong
winter range, winter of 1978—79 (January 7 , 1979 — March 6, 1979) .

Trap

No.

No. Trap
Nights

No. Deer
Caught

No. Deer/
100 Nights

No . New
Deer Tagged

l'

17

18

105.9

3

2

18

18

100.0

5

3

18

12

66.7

3

4

6

0

0

0

5

21

14

66.7

3

6

22

17

77.3

6

7

18

17

94.4

2

8

17

13

76.5

5

9

17

18

105.8

3

10

17

14

76.5

1

11

13

8

61.5

1

12

12

13

108.3

7

13

6

4

66.7

1

14

6

3

50.0

2

15

6

8

133.3

3

16^

21

55

261.9

9

TOTAL

235

232

98.7

543

^Trap numbers 1-15 were Clover traps.
^Corral trap.

^Eighteen additional new deer were marked

using the cannon net.

-76-

Table 2. Summary of mule deer trapped on the Armstrong winter range from
1972 through 1979 and their status as of June 1, 1979.

Year

Total No.
Marked

No. OK 6/79^'^

No. Dead

Unknown^^

1972

5

0

4(3)-^

1

1973

16

2

9(1)

5

1974

39

9

13(2)

17

1975

36

10

21(8)

5

1976

9

4

3(1)

2

1977

16

11

4(2)

1

1978

42

25

9(2)

8

1979

72

44

28 -

-

^Number

alive and accounted for on Armstrong

winter range

during spring

„ 1979.

^Includes four deer known to have left AWR in past years i

and wintered

„ elsewhere but were not

observed in 1978-79

.

, Number

shot by hunters

in parentheses.

^Includes 13 fawns and 1

yearling male that

have not been

observed since

early March and are believed dead.

Table 3.

Year of

last

observation

for

marked mule

deer of

unknown

status.

Year

Tagged

1972

1973

1974

1975

1976

1977

1978

Total

1972

0

1

1

1973

1

1

3

5

1974

2

4

5

4

2

17

1975

1

4

5

1976

1

1

2

1977

1

1

1978

8

8

TOTAL

0

2

3

5

10

9

10

39

-77-

Trapping was conducted on the Brackett Creek and Battle Ridge winter ranges
during mid-March and on a portion of the West Slope South Unit, near the
mouth of Bridger Canyon in mid-April. These operations employed a heli-
copter drive net. Within a 2J2-day trapping period, 81 new mule deer were
captured at Brackett Creek and 23 on Battle Ridge. Six of those trapped
on Brackett Creek were equipped with transmitter collars; the remainder
were neck-banded. Five mule deer were captured at the Bridger Canyon site,
of which two were radio-collared and three were neck-banded.

Following trapping, and as deer left the winter range, radio-collared deer
were relocated approximately weekly using receiving equipment from a fixed-
wing Piper Supercub aircraft. When or where possible, supplementary
relocations were obtained by ground tracking from a vehicle or on foot. As
in previous years, an effort was made to visually relocate all transmitter
equipped females to determine reproductive success and survival of fawns
during the summer.

Mortality records were obtained for the Armstrong area through field and
other contacts with hunters and landowners providing access, returns of
marked animals and, during winter, by general observations in the course
of trapping and other studies on the winter range. As in previous years,
(Mackie et al. 1976) , a systematic "dead deer survey" of the winter range
between North Cottonwood and Bill Smith Creeks was conducted in mid-May.

RESULTS AND DISCUSSION

Habitat Studies

Weather Conditions on Major Mule Deer Winter Ranges

Weather stations were established in late fall 1978 on the Armstrong, Schafer
Creek and Blacktall Mountain winter ranges along the west slope of the Bridger
Mountains and on the Livingston and Brackett Creek winter ranges on the east
slope. Two complete stations were maintained on Brackett Creek. Comparative
data were obtained from official U.S. Weather Service Stations at Bozeman
(MSU) for the west slope and Livingston (Airport) for the east slope.

Trends in mean maximum and mean minimum temperatures averaged for east and
west side stations are shown in Figure 2. Maximum daily temperatures varied
only slightly between winter ranges on the east and west slopes; while daily
minimums on the east slope averaged approximately 5°F lower during most of
the winter and early spring.

Mean monthly temperatures for the Schafer Creek and Livingston winter ranges
are compared with monthly means and 30— year "norms" at Bozeman and Livingston,
respectively, in Table 4. The monthly means were generally similar for all
stations, except during January, and showed similar trends from month to
month and in relation to long-term norms. They also show the record lows
which occurred from November through January on both the east and west slopes
of the Bridger Range. Temperatures moderated somewhat in February and were
near normal through April.

-78-

Figure 2. Trends in daily maximum and minimum temperatures on mule deer
winter ranges in the Bridget Mountains, October 1978— May 1979.

Table 4. Mean monthly temperatures ( F) recorded on the Schafer Creek and
Livingston winter ranges compared with monthly means and 30-year
averages for U. S. Weather Service stations in Bozeman (MSU) and
Livingston (airport) .

Nov.

Dec .

Jan.

Feb.

Mar .

Apr.

MSU

30 yr. ave.
1978-79

32.3

24.5

25.1

16.8

20.8

4.7

26.2

24.9

29.9

33.0

41.9

42.1

Schafer Cr.
Winter Rge.

1978-79

26.8

17.4

11.2

26.9

34.5

40.3

Livingston

Airport

30 yr . ave .
1978-79

35.2

27.3

28.9

17.4

24.8

*

28.6

27.3

31.4

•k

43.2

A

Livingston
Winter Ree.

1978-79

25.0

17.1

9.3

23.2

32.2

39.8

*Not available

-79-

Table 5 compares monthly (November-May) climatological data for the Bozeman
(MSU) weather station for the years 1971-72 through 1978-79. The severity
indicies (Picton and Knight 1969) indicate the 1978-79 winter was more severe
than any previous winter since the study began. Monthly severity indicies
for November, December and January also were the highest recorded, while that
for February was the second highest on record. Indicies for March and April
were about average for those months. Overall, the winter was characterized
by below average temperatures and slightly above normal precipitation.

Mean monthly wind speeds, computed from total miles of wind recorded over
weekly or occasionally longer periods, for the five major winter ranges are
presented in Table 6. These data indicate that east slope ranges were much
windier than west slope ranges. Higher average wind speeds, together with
similar or slightly lower average temperatures on the east slope could be
expected to result in a higher overall average wind-chill factor for winter
ranges along the east side as compared with those on the west slope. On the
other hand, generally higher winds combined with less total snowfall might
also be expected to result in lower total snow depths, especially on exposed
ridges and slopes, on the east as compared with west side ranges.

Table 7 shows snow depths and percentages of ground surface covered by snow
in the vicinity of weather stations on the five major winter ranges from
late December or early January through mid-April. Measurements were gener-
ally made at weekly intervals, except at the lower Brackett Creek (Pecken-
paugh) site where only one measurement was made in January and February
and at one site on the Blacktail Mountain winter range (Felix Canyon No. 2)
where measurements were made only during March and April. These data, com-
bined with general observations made earlier. Indicate that west slope
winter ranges were completely snow covered from 9 November 1978 through the
first week of March, 1979, when the snow cover began to rapidly disappear
from steep south and southwest facing slopes. Snow depths were greatest on
the Blacktail Mountain winter range, where the Felix Canyon snow course
showed depths ranging from 4.5 to 6 dm (l%-2 ft.) from December to mid-March.
This area was also the last to lose its snow cover, with substantial
accumulations persisting into April. The period of total snow coverage was
less prolonged on east slope winter ranges, especially on the Livingston
area where less total snowfall occurred and higher winds reduced snow depths
and frequently cleared exposed slopes and ridges. Observations indicated
that snow crusting occurred on west slope ranges between the 10th of February
and early March; but this condition may not have been as severe as in some
previous years due to the lack of mid-winter thawing and high winds. Crusting
appeared more prevalent on east slope winter ranges, but may have been less
important because of the generally lower snow depths and less complete
coverage.

Because the timing of "green-up" and the subsequent rate of phenological
development of plants has been considered important in the recovery of mule
deer from nutritional stresses of winter as well as in reproduction, phenology
and growth rates of some common plant species were measured on each of the
major winter ranges (Table 8) . These data indicate that some green-up and
new growth of grasses was under way on the Armstrong and Schafer Creek ranges
on the west slope and on the Livingston range on the ease side by the last
week of March. The relatively slow development of plants on the Blacktail
Mountain area probably was due to the late snowmelt, since other factors

Table 5 . Climatological data, MSU Weather Station, Bozeman, and severity indices, November through
May, 1971-1979.

Ave. Temp.
(°F)

Ppt . (in.)

Total
Snowfall
(in. )

Max . Snow
Depth
(in.)

No . Days
Snow on
Ground

Severity^

Index

November 1971

33.7

0.77

11.2

5

17

- 297

1972

32.8

0.63

3.0

4

8

- 250

1973

30.4

1.27

15.8

11

25

+ 104

1974

35.1

0.67

4.7

2

10

- 377

1975

30.5

1.33

20.5

12

15

+ 491

1976

35.5

.20

3.9

4

4

- 415

1977

31.7

1.19

12.0

8

11

+ 260

1978

24.6

1.87

17.0

9

26

+ 955

December 1971

20.8

0.56

11.1

10

31

+ 1161

1972

18.6

0.49

12.2

4

23

+ 1047

1973

29.5

1.29

20.5

13

16

+ 234

1974

25.5

1.02

13.2

6

31

+ 284

1975

30.0

1.10

15.8

6

22

+ 84

1976

30.3

.22

3.3

3

8

- 232

1977

25.2

1.19

12.7

8

22

+ 315

1978

16.8

.72

13.9

10

31

+ 1954

January 1972

19.1

0.86

13.8

10

31

+ 1068

1973

19.2

1.10

16.6

9

31

+ 1837

1974

21.3

0.42

5.8

14

25

+ 3743

1975

22.8

1.58

22.9

14

31

+ 1369

1976

26.6

0.60

8.7

9

28

+ 360

1977

30.3

.60

13.5

9

31

+ 583

1978

22.2

1.03

13.7

12

31

+ 842

1979

6.9

1.03

15.5

16

31

+ 5597

February 1972

31.0

0.66

10.2

6

27

75

1973

24.4

0.04

1.8

8

28

+ 483

1974

32.0

0.43

7.8

4

21

- 206

1975

21.3

1.11

19.5

17

28

+ 1659

1976

30.4

0.52

9.8

4

5

- 187

Table 5. (Continued).

Ave. Temp.

CXi

Ppt. (in. )

Total

Snowfall

(in.)

Max . Snow

Depth
(in. )

No. Days
Snow on
Ground

Severity^

Index

1977

33.8

.06

1.0

3

17

322

1978

26.3

.87

15.1

11

28

4-

892

1979

25.0

.75

11.5

18

28

+

1354

March

1972

41.0

1.24

13.6

8

8

—

586

1973

33.9

1.89

23.0

11

31

—

303

1974

32.6

1.71

24.7

7

26

_

206

1975

29.1

1.08

20.7

9

31

+

295

1976

28.7

1.03

18.5

6

12

+

262

1977

30.9

2.39

27.0

8

23

—

184

1978

37.2

.74

4.6

10

19

+

59

1979

33.0

.77

10.1

14

31

_

125

April

1972

41.3

1.91

21.9

4

5

-

652

1973

38.9

2.84

34.7

14

14

—

520

1974

45.8

1.87

3.2

0

0

—

764

1975

32.9

1.77

16.1

8

24

_

141

1976

43.4

3.35

21.9

4

4

—

663

1977

48.1

.57

5.7

8

4

—

875

1978

44.9

.93

1.4

trace

0

-

692

1979

42.1

1.93

18.1

1

9

—

623

May

1972

50.7

1.73

trace

1

0

-

958

1973

51.4

1.44

1.3

trace

0

—

989

1974

48.3

3.00

12.1

3

3

_

880

1975

46.9

4.88

21.5

9

6

-

803

1976

55.5

1.95

trace

0

0

-

1157

1977

50.3

3.84

3.4

0

1

946

1978

49.7

4.04

1.0

0

0

-

886

1979

60.7

3.66

1.3

0

3

—

1269

Table 5. (Continued) .

Ave. Temp.
<^>

Ppt. (in.)

Total

Snowfall

(in.)

Max . Snow
Depth
(in. )

No . Days
Snow on
Ground

Severity

Index

Nov. -

May 1971-72

33.9

7.7

81.8

10

119

- 329

1972-73

31.3

8.4

92.6

14

135

+ 1335

1973-74

34.3

10.0

89.9

14

116

+ 2025

1974-75

30.5

12.1

118.6

17

161

+ 2286

1975-76

35.2

9.9

95.2

12

86

- 810

1976-77

37.4

7.9

57.8

9

88

- 2391

1977-78

33.9

10.0

60.5

12

111

+ 790

1978-79

29.9

10.7

87.4

18

159

+ 7843

20 Year Ave.

32.4

9.5

1

+ Values indicate greater severity.

-83-

Table 6. Mean monthly wind speeds
the Bridget Mountains.

(MPH)

recorded

on five

mule deer winter

ranges

in

PERIOD

Station

Dec.

Jan.

15-

5

Jan. 6-
Feb. 2

Feb.

Mar.

3- Mar. 3-

2 Mar. 30

Mar .
May

31-

4

Schafer Creek Winter Range

2.19

0.84

1.58

1.5ll

1.85

Armstrong Winter Range

3.19

1.56

2.89

2.23

2.73

Blacktail Mt . Winter Range
(Felix Canyon)

3.42

2.06

2.52

2.50

2.80

Brackett Cr. Winter Range
(Lef f ingwell)

6.53

3.85

5.41

3.94

3.97

Brackett Cr. Winter Range
(Peckenpaugh)

8.54

4.27

6.76

5.14

6.82

Livingston Winter Range

8.38

5.55

7.55

5.59

6.55

^From three weeks data.

Table 7. Snow depths and coverages recorded on five mule deer winter ranges, 1978-79.
Depths are In decimeters, coverage is in percent of ground covered.

Dec.

January

February

March

Apr

il

28

5

12

19

26

2

9

16

23

2

9

16

22

30

6

13

Schaf er

D^

2.2

2.8

3.1

3.3

3.5

3.8

3.6

2.4

2.2

2.7

.7

0

0

0

0

Cr. W.R.

C^

100

100

100

100

100

100

100

100

100

100

68

03

Armstrong

D

2.4

2.8

M

3.5

3.4

3.9

3.5

2.4

2.4

3.1

1.4

0.1

0

0

0

W.R.

C

100

100

100

100

100

100

100

100

100

100

92

1*+

Blacktail

D

4.5

M

M

5.2

5.1

5.3

4.6

4.8

5.2

5.8

4.4

2.9

2.1

1.5

1.0

0.1

Mt. W.R.

C

100

100

100

100

100

100

100

100

100

100

100

95

81

69

57

8

(Felix Canyon

Jl)

Brackett

D

2.7

4.2

3.2

3.6

3.7

2.7

3.2

2.8

5.1

2.0

*4

0

0

0

0

Cr. W.R.

C

100

100

98

100

100

100

100

92

100

48

(Lef f ingwe

11)

Bracket

D

2.8

2.6

0.7

*

0

0

0

0

Cr. W.R.

C

100

100

25

(Peckenpau

Rh)

Livingston

D

1.0

1.3

0.9

0.8

0.7

*

*

*

3.5

i<

*

0

W.R.

C

98

100

88

100

98

100

Blacktail

D

4.4

3.6

1.8

1.5

1.0

1.0

0.7

Mt. W.R.

C

100

100

79

61

40

37

36

(Felix Canyon

//2)5

^Snow depth (Decimeters)

^Snow coverage (Percent)

^Snow was gone from the snow course but was still 1-2 dm deep on the flats below.
**Only scattered drifts left

^Second Felix Canyon snow course, established 3/2/79
M - Data missing

-84-

Table 8. Spring phenology on five winter ranges in the Bridget Mountains
March 29-May 11, 1979.

Ichafer Creek and Armstrong W.R. Blacktail Mt . W.R. (Felix Canyon)

Species

3/29

4/6

D

4/13

ate

4/20

5/1

5/4

5/11

3/29

4/6

E

4/13

ate

4/20

5/1

5/4

5/11

AGSpl

FEID

KOMA

CHVI

BASA

2(2)^

2(2)

2

9

2(2)

2(2)

2

9

2(3)

2(3)

2

9

2(3)

2(4)

2

9

3(5)

3(6)

2

1

3(5)

3(6)

2

1

3(7)

3(6)

3

2-4

9

9

9

2(1)

1

9

2(1)

1

9

2(1)

2(1)

9

2(2)

2(2)

9

2(2)

2(3)

1

2(2)

2(3-4)

3(2-3)

1

AGSP

FEID

KOMA

CHVI

BASA

Bracket Creek W.R. (Lef f ingwell)

3(6)

3(3)

Bracket Cr . W.R. (Peckenpaugh)

3(5) .

3(2)

2

2(2-3)

2(1-2)

3(3)

2(2)

3(3)

2(2)

3(4)

2(2)

3(5)

2(3)

2(1)

2(1)

2

2(2)

2(1)

2

2(2)

2(1-2)

2

3(3)

3(2)

2

3(4)

3(2)

2

AGSP

FEID

KOMA

CHVI

Livinj

?ston 1

7.R. north-facing slopes

Livingston W.R. south-facine sloop??

9

2(h)

9

2(1)

2(1)

2(1)

2(1)

2(1)

2(1-2)

2(1)

2(2)

2(1)

2(3)

2(2)

2(1)

2(2)

2(1)

9

2(2)

2(3)

2(1)

2

2(2)

2(3)

2(1)

2

2(3)

2(3)

3(2)

2

3(6)

3(6)

3(2)

2

3(6)

3(6)

3(2)

2

3(6)

3(6)

3(2)

3

^ ^G^Agrop^Jr‘on spiaatim, ¥ElT)=Festuca idahoensis,
villosa, EkSA-Balsamovhiza sagittata.

¥SMk=Koelevia maorantha, CH\!l=Chrysopsis

^Phonological state. Phenological stages are: 1) Recent emergence or leaf bud,

2) Early leaf, 3) Full leaf, 4) Early flower (bud), 5) Full flower, 6) Early fruit
7) Mature fruit, 8) Post seed drop, 9) Dead or dormant.

In parenthesis -height in inches given for grasses only.

influencing plant growth and development were essentially the same as on other
west slope ranges. The relatively slow development of bluebunch wheatgrass
(AGSP) on the Brackett Creek (Peckinpaugh) range might be explained by the
location of the phenology transect on a flat, level hilltop rather than a
warmer, south-facing slope like other sites.

Generally, the onset of spring green-up and rate of early phenological
development appears later or slower than normal. However, phenological data
for lilacs in Bozeman (D.K. Scharff, pers. comm.), listed in Table 9, in-
dicate that early bud development occurred very close to the ave-age date
while full bloom occurred nearly a week earlier than normal. This might in-
dicate about average early growth and development of plants in the area and
somewhat faster development later in the spring.

-85-

Table 9. Phenology of lilac development and growth in Bozeman, Data

provided by Donald K. Scharff, Professor, Biology Dept., Montana
State University, Ret,

Year

Early Bud
Stage!

Lush Full
Bloom^

Remarks

X 1955-1970

12 May

8 June

1971

11 May

10 June

1972

3 May

31 May

1973

16 May

11 June

1974

3 May

13 June

1975

18 May

24 June

Latest recorded for both

1976

-

2 June

1977

25 April

28 May

2nd earliest recorded for both

1978

20 May

28 May

Earliest recorded for both

1979

13 May

2 June

^Early bud stage
new growth will

= first sight of
be about 1" long

flower buds.

leaf buds will be open and

2

Peak of bloom

Vegetation Classification and Mapping

Detailed vegetation classification for the Bridger Range was initiated in 1972
with studies by Buscis (1974) on the Armstrong Winter Range. This effort was
continued and expanded to other areas by Pac (1976), Jorgensen (1977), Steerey
(1979), and Nyberg (1978, In Prep.). Through these efforts of workers, ground
truth reconnaissance of varying intensity has been accomplished for the Livingston
and Brackett Creek winter ranges. Bangtail Ridge, the north end of the Bridger
Range from Flathead Pass to Tom Reese Creek (including the Armstrong winter
range) and the southern part of the Bridger Range along the west slope from
Mizer Canyon to Middle Cottonwood Canyon. Preliminary vegetation mapping
was accomplished for seasonal ranges occupied by the Armstrong and Schafer
Creek herds. Intensive mapping has been completed for the northern and
western portions of Bangtail Ridge, including parts of the Bridger and Brackett
Creek drainages.

-86-

At present, 87 different vegetation entities have been recognized within
the Bridget complex. These range from the vegetation on heavily disturbed
sites, such as grain fields, to virtually climax stands of forest. Many
of these types are, in realty, serai stages of, and may be grouped together
under, a smaller number of habitat types (vegetal-geological-climatic
entities in near climax condition) . The habitat type classification employed
for forested areas of the Bridger Range follows that of Pfister, et al. (1977).
Since the ecology and successlonal relationships of the nonforested areas
is not well understood, vegetational entities associated with these areas
will be delineated only as cover types at the present time. If and when
successlonal relationships are established, nonforested cover types will
also be grouped into habitat types.

Data collection and analyses are not sufficiently complete to facilitate a
detailed discussion of the ecology and spatial distribution of all the cover
and habitat types within the Bridger Range; though fairly detailed descriptions
of some habitat types were presented by Buscis (1974), Pac (1976), and
Steerey (1979) . Table 10 lists the occurrence and some ecological character-
istics of various habitat and cover types presently recognized in various
study areas in the Bridger Mountain complex. Future analyses will be directed
to possible relationships between the occurrence and other attributes of
various types within range areas occupied by the Armstrong, Schafer Creek
and Brackett Creek deer populations and the distribution, density and
dynamics of mule deer associated with these ranges.

Nutritional Analysis of Forage Plants

Previous analysis of crude protein in plants collected from the Armstrong
summer range were reported by Pac (1976) and analysis for protein plus
certain mineral elements in plants on the Armstrong winter range were reported
by Morton (1976). During 1978-79, additional data were obtained concerning
1) changes in crude protein content of some major forage plants through the
summer, 2) the relationship between percent protein on a wet weight basis and
dry weight basis, 3) the effects of site differences (mainly altitude) on
protein content of plants of the same species, 4) the differences or similar-
ities in protein content between forbs and shrubs, and 5) the relationship
between phenological stages and protein content.

The results showed steady declines in percent protein on a dry weight basis
as the growing season progressed. (Table 11, Figures 3 and 4). These findings
are in agreement with results from similar studies (Dietz, et al. 1958, Wallmo,
et al. 1977, Urness, et al. 1975, Williams 1953, Payne 1955 and others). When
protein percentages were plotted on the basis of phenological stages rather
than calendar dates (Figures 3 and 4) it became evident that the curves
showing the decline in protein as development progressed were quite similar for
the same plant species whether it was collected at a high or low elevation
site. This suggests that at least part of the difference in protein content
within the same species collected on the same date but at different elevation
sites (Table 11) was due to the different stages of phenological development
at the different sites. Only one species, Vaoainiim saoparium, exhibited lower
protein content at the very early leaf stage than at a later phenological
stage; however, not all species were collected in the early leaf stage.

Table 10. Ecological characteristics and distribution of habitat and cover types on various study areas
in the Bridget Mountain complex. ^

Forested

Habitat

Types

Bucsis

North

Bridget

Winter

Ranges

Pac

North

Bridget

Summer and

Transitional

Ranges

PSME^ Series

PSME/ACSP

+2

PSME/FEID

+

PSME/ CACE

+

+

PSME/SYAL

+

SYAL phase

+

CARU phase*
AGSP phase
PSME/PHME

Steerey

South

Bridget

Summer and

Winter

Ranges

+

+

+

+

+

CARU phase*
PSME/CARU
CARU phase*
PSME/PRVI +

PSME/VAGL
VAGL phase*

+

+

+

+

+

Nyberg

Bangtail

Summer

Range

+

+

+

+

+

+

+

+

Nyberg

Brackett

Creek

Winter

Range

Jorgensen

Livingston

Winter

Range

+

Restricted

to

Elev. Limestone

low

low

mid

low

low-mid

low

low

mid

low

mid

Restricted

to

Igneous

ABLA Series
ABLA/CACE
CACE phase*
PSME phase*
ABLA/CARU*
ABLA/VACL*
ABLA/ CLP S
ABLA/ARCO*
ABLA/VASC
VASC phase
THOC phase
CARU phase*
ABLA/ALSI
SALIX phase

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

high

mid

mid

raid

high +

mid

high

high

mid

mid

+

+

+

I

00

I

Table 10. (continued) .

Bucsis

Pac

Steerey

North

North

South

Bridger

Bridger

Bridger

Forested

Winter

Summer and

Summer and

Habitat

Ranges

Transitional

Winter

Types

Ranges

Ranges

PINUS Series

PIFL/JUSC

PIFL/JUCO

+

+

PIAL/VASC

+

PIAL/CAGE

+

Other

PICEA/PHMA

PICEA/GATR

POTREM/SALIX

POTRICH/PRVI

JUSC/PRVI

+

Nonforested

Habitat

Types

AGSP/ORHY

AGSP/FEID
AGSP/ARTR
PUTR phase
AGSP/AGSM
AGSP/PSME
RHTR/AGSP

+

PIFL phase
FEID/AGSP +

FEID/AGSM
FEID/CAHO
FEID/ARLU
FEID/BRCA
FEID/ANRO

ARTR/FEID +

AGSP phase
POPR phase

Nyberg

Bangtail

Summer

Range

+

+

+

+

4-

+

+

+

Nyberg

Brackett

Creek

Winter

Range

Jorgensen

Livingston

Winter

Range

Elev.

Restricted

to

Limestone

Restricted

to

Igneous

+ low

high
high
high

low

mid

low

low

low

+

4-

low

+

+

low

+

low

low

+

low

4-

low

4-

4-

low

4-

low

mid

mid

raid

mid

4-

4-

low

4-

low

+

+

+

I

00

00

I

Table 10. (continued).

Bucsis

Pac

Steerey

Nyberg

Nyberg

Jorgensen

North

North

South

Bangtail

Brackett

Livingston

Bridget

Bridget

Bridget

Summer

Creek

Winter

Nonf orested

Winter

Summer and

Summer and

Range

Winter

Range

Restricted

Restricted

Habitat

Ranges

Transitional

Winter

Range

to

to

Types

Ranges

Ranges

Elev.

Limestone

Igneous

ARTR/AGSP +

AGDA phase

+

low

POPR/ARTR

+

+

low

POPR/FEID

+

low

POPR/PHPR

+

low

POPR/SYAL

+

+

low

PUTR/AGSP

+

low

PUTR/ARTR

+

low

JUSC/PUTR

ARTR phase

+

low

AGSP phase

+

low

FEID phase

+

low

TRHA/LOCO

+

v.high

ABLA/RIBES

+

v.high

CRSU/AMAL

+

low

SALIX/ALSI

+

low

ACGL/PHLE

+

low

Mayfields

+

+

low

Grain Fields

+

+

low

+

+

^Species abbreviations used in names of types:
PSME - Pseudotsuga menziessii (Douglas fir)

AGSP - Agropyron spicatum (bluebunch wheatgrass)
FEID - Festuca idahoensis (Idaho fescue)

CAGE - Carex geyeri (elk sedge)

SYAL - Symphoricarpus albus (snowberry)

CARD - Calamagrostis rubescens (pinegrass)

PHMA - Physocarpus raalvaceus (ninebark)

PRVI - Prunus virginiana (chokecherry)

VAGL - Vaccinium globulare (huckleberry)

ABLA - Abies lasiocarpa (subalpine fir)

CLPS - Clematis pseudoalpina (clematis)

ARGO - Arnica cordifolia (heartleaf arnica)

^’’+" means yes, blank space means no.

*Indicates those habitat types of phases
(lodgepole pine) following disturbance.

VASC - Vaccinium scoparium (grouse whortleberry)
THOC - Thalictrum occidentale (western meadow rue)

ALSI - Alnus sinuata (thinleaf alder)

SALIX - Salix sp . (willow)

PINUS - Pinus sp. (pine)

PIFL - Pinus flexilis (limber pine)

PIAL - Pinus albicaulis (whitebark pine
JUCO - Juniperus communis (common juniper)

JUSC - J. scopulorum (Rocky Mountain juniper)

PICEA - Picea sp. (spruce)

POTREM - Populus tremuloides (quaking aspen)

POTRICH - P. trichocarpa (black cottonwood)

in which the dominant climax tree may be replaced by Pinus contorta

I

-68

Table 11.

Percent crude protein of important mule deer forage plants collected within the
Armstrong herd range in 1978 - wet^ and dry basis.

Species

Wet

Site or
Kiev. Dry

June

July

August

13

22

26

12

24

27

17

September
1 3

October
2 18

Thaliatrum

venulosum

8200

D

W

30.9

4.8

25.0 25.2 18.7

4.4 4.9

15.3 17.5

4.0 ? ^

10.6

2.9

12.8

8.4

7200

D

W

29.2 27.2

5.2 8.5

17.2

4.3

9.4 10.6

2.9 ?

6 . 6
2.2

7.2

3.9

6200

D

W

20.1 19.1

4.0 4.2

12.2

3.4

6.8

2.9

4.7

3.0

Geranium

visaossissimum

8200

D

W

22.5

3.8

22.3 19.9 16.2

4.5 4.3 3.5

13.3 12.9

3.1 ?

4.7

3.0

7200

D

W

23.2 22.7

4.4 3.8

16.8

3.3

12.5

3.0

6200

D

W

15.8 13.5

3.2 3.1

11.6

2.7

8.5

2.8

Balsamorhiza

sagittata

7680

D

W

23.2 24.4

4.3 4.9

20.1 15.2

4.4 4.7

12.6

9

5.3

1.7

9.2

8.3

6000

D

W

21.5 17.7

4.4 4.6

13.3

3.8

6.5

2.6

4.5

4.3

5.4

4.6

Trifo Hum
haydenii

8300

D

W

28.4 29.5 21.4

4.5 5.6 4.8

17.0

4.8

13.3

4.6

14.0

7.2

Vaacinium

glohulao'e

7680

D

W

24.7 21.6

5.8 4.7

11.4

3.3

8.9

3.4

7.7

3.0

6800

D

W

19.5 14.2

4.6 3.8

11.4

3.8

8.7

2.9

6.4

2.6

6.0

2.4

6200

D

W

14.7 13.7

3.6 3.9

11.4 8.5

3.9 2.5

7.8

3.0

5.3

2.0

Symphoriaarpus

albus

6880

D

W

20.6 17.3

5.2 5.1

13.3

4.4

10.4 10.2

7.0 ?

6.0

2.3

6200

D

W

14.4 12.4

3.7 3.6

11.5 10.6

3.8 3.7

10.9

3.7

8.0

3.0

6.3

2.2

Vaaainium

saoparium

7680

D

W

8.6 11.2
3.5 3.8

9.6

3.4

8.3

?

6.9

2.9

6.9

3.1

^Percent nitrogen on a wet wt. basis calculated as follows: %N^ - (^^p) (<^ty wt of sample)

wet wt of sample

where %Nd = percent nitrogen on oven dry basis.

I

0

1

^The wet weight data for some of the samples were lost, making it impossible to calculate the /iN on a wet
weight basis.

Figure 3. Seasonal trend in percent protein, dry weight basis, forbs, 1978.

For description of phonological states see Table 8, p. 34.

Figure 4. Seasonal trend in percent protein on a dry weight basis, shrubs, 1978.

-92-

Dry weight protein contents of most shrubs collected in early phenological
stages ranged from 14 to 25/2. However, by the end of the growing season,
the range in protein content for all the shrubs was much narrower and was
very close to the minimum percentage considered necessary for mule deer
maintenance.

The protein content of forbs on a dry weight basis ranged somewhat higher
than for shrubs in early stages of phenology, but declined during autumn
to levels near the minimum percentage for deer maintenance. However, the
range of values at this time was greater than for shrubs (Figs. 3 and 4).
Protein content of forb species collected at high and low elevation sites
were similar during most of the development period. At the stage of dormancy,
however, plants at high elevation sites maintained greater percentages of
crude protein. One explanation for this may be that those plants collected
at higher elevations, although dormant, had not progressed as far into
dormancy, and lost less protein from the leaves than plants collected at
lower elevations.

The data were also analyzed on the basis of percent protein per unit of
forage wet weight since high water content of forage during spring and
early summer could dilute protein levels to the extent that deer may have
obtaining adecjuate amounts. Results showed rather convincingly
(Figs. 5 and 6) that in spite of the high water content early in the
season, the percent protein on a wet weight basis for shrubs was still
slightly higher in spring than fall and remained about the same for forbs
at moderate elevations. At high elevations in the fall, the percent protein
on a wet weight basis increased sharply for all the forbs tested as a
consequence of having a relatively high protein content, coupled with a
very low moisture content. One may conclude that high water content of forage
species in spring and early summer probably do not effect the ability of deer
to obtain protein at that time. The availability of protein at high elevations
in the fall (i.e. 8000-8500 feet as investigated here) may be greater than at
any other locations at any other time.

Figure 5. Seasonal trend in percent crude protein on a wet weight basis
forbs, 1978.

-23-

Figure 6. Seasonal trend in percent crude protein on a wet weight basis,
shrubs, 1978.

Distribution, Movements and Habitat Use

Wint er

General distributional characteristics of mule deer in the Bridget Range
during winter were described by Mackie et al. (1978). Overall distributions
recorded in early and late winter aerial surveys during 1978-79 were generally
similar to previous years. The only differences observed were in local
distributions within major winter range boundaries during late winter.

Notable in this respect were: 1) an extreme concentration of deer on that

portion of the West Slope-South Unit which lies within the mouth of Bridger
Canyon and 2) the apparent movement or shift of large numbers of mule deer,
possibly 200-300 from the Blacktail Winter Range north to the 16-Mlle Creek
area. Also, the Hatfield Mountain-South Fork portion of the South 16-Mile
Winter Range held very few deer in both early and late winter. Other
differences were even more local and expected from previous observations
under the severe weather and snow conditions which prevailed throughout the
winter. The fact that no mule deer have been marked in any of the areas
on which significant distributional changes occurred precludes further analysis
of the movements at this time. Observations on the intensively studied
Armstrong, Schafer Creek and Brackett Creek winter ranges throughout the
winter indicated that by mid-winter most animals were confined to primary
or critical range areas within the total winter ranges. These concentrations
began to break up on the Brackett Creek area in late February (Nyberg In Prep.),
but persisted into mid-March on west slope winter ranges.

The recently completed, intensive studies of winter habitat use of radio-
collared deer on the Armstrong study area (Youmans 1979, see abstract in this
report) have contributed significantly to our understanding of winter distri-
bution and habitat use on that area. Especially notable was documentation of
three subunits, comprising the north, central and south portions of the
Armstrong winter range. These were relatively discrete, with only slight

-94-

overlap between north and central and central and south units. The distri-
bution and movements of individual marked does were almost totally restricted
to the individual subunits on which they were marked. Some apparent relation-
ships between this pattern of winter distribution and other seasonal distri-
bution as well as implications in the dynamics of mule deer on the Armstrong
area will be discussed later. The findings of this study also indicated that
usage of various habitat and cover types varies between deer associated with
each of the subunits and that previous analysis of habitat usage based on
general observations probably have greatly underestimated the use and impor-
tance of timbered types. They further suggested that habitat usage reflected
a strategy of energy conservation rather than forage gathering.

Summer

Substantial data on spring-summer-fall distribution, movements and habitat
usage of deer in the Bridger Range have been obtained for animals associated
with the Armstrong, Schafer Creek and Brackett Creek winter ranges. Some
limited data on seasonal movements have also been obtained for deer wintering
near the mouth of Bridger Canyon. Findings for the Armstrong population have
been reported and discussed by Schwarzkoph (1973), Hamlin (1974, Pac (1976),
Mackie et al. (1976), Mackie and Knowles (1977) and Mackie et al. (1978).

Data for the Schafer Creek population were discussed by Steerey (1979), while
Nyberg (in prep.) presents findings for deer associated with the Brackett
Creek winter range.

As reported by Mackie et al. (1978), all 800 square miles included in the
study area may be used by mule deer during spring, summer and fall. Most
summer-fall activity and use by mule deer occurs within the Bridger Range
at elevations above about 5,600 feet or within an area encompassing approx-
imately 434 square miles. Notable exceptions occur where deer continue to
use winter ranges and agricultural crop and rangelands below 5,600 feet.

Spring dispersal and summer distribution and movements of deer associated
with the Armstrong winter range were discussed by Mackie and Knowles (1977)
and Mackie et al. (1978). Additional data obtained during 1979 showed gener-
ally similar dispersal and summer movements and supported earlier conclusions.
Four deer first equipped with transmitters in late winter 1979, moved off the
winter range in a northerly direction. One spent the summer at low to moderate
elevations in the North Cottonwood drainage, the second utilized foothill
slopes south of Mill Creek, the third moved to an upper tributary of Mill
Creek, and the fourth summered at the head of Johnson Canyon. One of the two
deer radio-collared on winter range in lower Tom Reese Creek spent the summer
just east of the winter range, while the other crossed the Bridger Divide and
summered along the South Fork of Carrol Creek.

Generalized summer home range polygons for all radio-collared deer for which
movements off the Armstrong range have been monitored since 1975 are shown in
Figure 7. The drainages most frequently used by Armstrong deer were Bill
Smith and North Cottonwood Creeks, where 15 of 30 (50%) radio— collared deer
spent the summer. Six of the 30 (20%) had summer home ranges in the Mill,
Johnson, and Pass Creek^ drainages . The east slope of the Bridger Range was
utilized by 7 of 30 (23%) individuals with most summering in Frazier Creek
and Carrol Creek. The remaining two (7%) had summer home ranges in Tom Reese
Creek. These data, together with similar findings for deer marked on the
Schafer Creek and Brackett Creek winter rangefe, support the suggestion
(Mackie et al. 1978) that deer associated with the various winter ranges in
the Bridger Mountains comprise population units which occupy fairly distinct
and definable herd ranges.

-95-

LEGEND

CREEK

ROAD

ELEVATION LINE

MOUNTAIN PEAK

mountain pass

ARMSTRONG WINTER RANGE

Figure 7. Generalized summer home range polygons for 30 mule deer
radio-marked on the Armstrong winter range 1975-79.

-96-

Generalized summer dispersal patterns of marked deer off various winter ranges
in the Bridget Mountains are shown in Figure 8, These data also illustrate
the general location and the relationships between individual herd ranges.

The Armstrong herd range appears to be bounded on the north by Pass Creek and
Flathead Creek, on the east by State Highway 293, on the south by North Fork
of Brackett Creek and Tom Reese Creek, and on the west by Foster Creek. The
Schafer Creek herd range extends north to Jones Creek, east to Bangtail Ridge
and as far south as Beasley Creek. The Brackett Creek herd range is bounded
on the north by Battle Ridge, on the east by Shields River, on the south by
Interstate 90 and on the west by State Highway 293, although a few deer move
as far as the Bridget Divide. Data for deer wintering near the mouth of
Bridget Canyon are limited. Relations of two deer, radio-collared in April
1979, showed that one spent most of the summer on and adjacent to the winter
range; the other moved north to summer in Pine Creek.

Overlap occurs between individual herd ranges and seems to be more prevalent
in particular areas. The east and west slopes of Bridget Canyon is one portion
of the Bridget Range where deer from the four winter ranges may "mix" somewhat
during summer and fall.

Yearlong movements of radio-collared and neck-banded deer associated with the
Armstrong range have shown that individuals using subunits or particular por-
tions of the winter range (Youman's 1979) may be at least generally associated
with particular portions of the summer herd range (Figure 9) . Deer that use
the northern portion of the winter range and belong to subunit 1 tend to dis-
tribute themselves in the northern part of the herd range. Individuals
belonging to subunit 2 on the winter range generally spend the summer in the
central and southern parts of the herd range while the greater percentage of
subunit 3 deer spend the summer on the east slope of the Bridgets. There are
numerous exceptions with considerable overlap occuring between individuals
from the three subunits. In general, males appear less consistent in their
distribution patterns than females and some may change either their summer
or winter home ranges between years. Also, movements of some adult males
during the breeding season have been erratic and involved temporary movements
outside the normal herd range. Several young males have been known to
emigrate and become "residents" of other herd ranges. We have no positive
record of any marked female of any age dispersing from the Armstrong herd
range or changing a seasonal home range between years. However, an adult
female marked on Brackett Creek in March 1978 spent the following winter 7
miles to the north on the Battle Ridge winter range.

Population Characteristics

Trend and Dynamics of the Armstrong Deer Population

Trends in estimated mule deer numbers and the sex and age composition of late
winter-spring population on the Armstrong winter range from 1973 through 1978
were discussed in detail by Mackie et al. (1978). Population estimates for
mule deer using the Armstrong winter range during 1977-79 are presented in
Tables 12 and 13, These were developed as Lincoln (Overton and Davis 1969)
and Schnabel indicies for observations of marked and unmarked animals during
early and late winter.

-97-

Figure 8

Generalized dispersal patterns of mule deer associated with various
winter ranges in the Bridger Mountains.

-98-

ROAD
CREEK

ELEVATION LINE
MOUNTAIN PEAK
MOUNTAIN PASS
ARMSTRONG WINTER RANGE
Subunit of winter range north portion
Subunit of winter range central portion
Subunit of winter range south portion

Figure 9. Relationship between winter and summer distributions among mule
deer marked on the Armstrong winter range, 1972 - 1979. Small
numerals indicate summer locations of deer associated with
correspondingly numbered subunits of the winter range. Triangles
around numerals indicate males.

-99-

Cumulative gi'ouiid, aerial and trapping records provided knowledge of the
numbers of marked deer on the area throughout the winter. At the end of April,
approximately 105 animals wearing recognizable collars were on the winter
range. It is possible that even more marked animals could have been present
since 13 fawns and 1 yearling male marked during 1979 and 39 adults tagged in
previous years but not observed during the 1978-79 winter were not included
in the spring total. All marked adults observed in early winter 1979 were
accounted for in spring. Because of this, the 13 missing fawns, last seen
prior to early March, were believed to have died. The yearling male was last
seen in early March in very poor physical condition. Ten of the 39 adults of
unknown status were last seen during the spring of 1978, while the remainder
have not been observed since the spring of 1976 or earlier (Table 3).

The mean percentage of collared deer in April observations made between Bill
Smith and North Cottonwood Creeks was 69.2 percent, ranging from 59.3 to 75.0
percent in daily observations. Between 25 and 45 percent of all deer on the
Armstrong range were marked at various times during the previous five winters.

For spring 1979, a population of 140 animals is believed to represent the
best estimate of mule deer numbers on the Armstrong winter range. The mean
Lincoln index for 12 ground surveys in April, was 140 mule deer (Table 12).

The Schnabel index was similar at 139 deer. A point estimate of 140 deer is
also obtained assuming a total collared deer population of 98 animals to repre-
sent 70 percent of all deer using the area between Bill Smith Creek and North
Cottonwood Creek. Lincoln and Schnabel indicies indicate that approximately
50-60 deer used the area between Bill Smith and Tom Reese Creek just south of
the Armstrong winter range. Interchange of individuals between this group and
deer wintering on the southern portion of the Armstrong range apparently occur
during some winters, and may be more frequent following spring green-up.

Estimates of mule deer numbers on the Armstrong range during early winter
(Figure 10) generally are more difficult to obtain than those for late winter,
when the population is much more concentrated, the deer use open habitat types,
and maximum numbers of marked deer occur. Using over -winter mortality rates
of marked adults and fawn: doe ratios observed during classification flights
in December, an early winter population numbering about 234 deer was expected.
This would have included about 110 adult females, 6 adult males, 15 yearling
males, and 102 fawns.

The estimated 140 deer on the Armstrong range in early spring 1979 included
approximately 104 adult females, 6 adult males, 11 yearling males, and 19 fawns
(Table 13). These data compared with estimates for early winter indicated
substantial over -winter mortality. Approximately 94 animals died, or 40
percent of the early winter population.

Known deaths included 36 deer found dead during the winter or during a system-
atic search for carcasses in late April (Table 14) . Mortality was severe
among fawns, the total possibly reaching 81 percent of early winter numbers.
Among 37 fawns marked between early January and early March, 30 percent were
found dead while an additional 32 percent were unaccounted for in the spring
and believed dead. Other losses, not documented in losses of marked fawns,
probably occurred as a result of severe early winter weather before and during
the trapping period.

-100-

Table 12. Late winter estimates of numbers of mule deer on the Armstrong
winter range, April, 1979.

Estimated Numbers
Total S

Remarks

140 11.06

X Lincoln Index for 12 ground surveys (47-123

deer obs/survey) and 95-98 collars in

population.

139

Schnabel Index for 12 ground surveys (47-123

deer obs/survey) and 95-98 collars in

1

—

population.

Table 13. Estimated late winter-spring mule deer populations on the
Armstrong winter range, 1973-1979.

fear

Total

Number

No. Adult
Females

No.

Adult

Males

Yearling

No. Fawns

1973

230

123

31

27

49

I974I

220

130

27

23

40

1975

140

92

35

8

5

1976

170

118

37

3

12

1977

200

120

24

6

50

1978

160

116

6

6

32

1979

140

104

6

11

19

No population estimate calculated. A spring population slightly lower
than that of 1973 is assumed consistent with fawn production and
survival for 1973 and 1974 and an early winter estimate of 210 mule
deer on the range in January 1975 (Mackie et al. 1976).

Table 14. Number and age classes of winter-killed mule deer found on the
Armstrong winter range, 1971-1979.

Year

Total

Fawns

Yearling

Prime

Old Unknown

1971-1972

19

9

_

10

1972-1973

18

12

-

1

5

1973-1974

12

10

-

—

2

1974-1975

42

16

2

10

14

1975-1976

2

2

—

_

1976-1977

2

-

-

1

1

1977-1978

25

11

-

—

7

7

1978-1979

36

26

2

1

6

1

TOTAL

156

86(55.1%)

4(2.6%)

13(8.3%)

45(28.8%:

8(5.1%:

Figure 10.

Early winter population trend

Mountains, 1972-79,

of mule deer on the

Armstrong winter

range.

Bridger

I

H

0
I-

1

-102-

The time of mortality among marked fawns apparently varied by sex. Mortality
of female fawns was most prevalent in January and February while male fawns
succumbed in late March and early April. The latter occurred after the March
12 aerial classification of t^e Armstrong range (Table 15). The sex ratio of
fawns that survived was 180'^/100^. Mortality records also indicated that
fawn losses were not evenly distributed across the Armstrong winter range.
Approximately 79 percent of all fawns marked on the northern portion of the
area died or apparently died while only 44 percent of those marked on the
central portion were not accounted for in spring.

Adult losses were comparatively light and totaled approximately 8 percent.
Mortality of females and males was estimated at 5 percent and 24 percent,
respectively, among marked adults.

Data obtained through trapping and marking together with intensive aerial and
ground observations have provided basis for annual estimates of the size and
sex-age composition of the Armstrong mule deer population during late spring,
1973-1979 (Table 13). To further evaluate trends and year-to-year dynamics,
annually obtained data were used to develop a mathematical model of the
Armstrong population using a computor population simulation program (POSIM
Mooney and Lonner 1978).

A brief summary of POSIM data analysis and output are shown in Table 16. For
data in some years, discrepancies occurred between mortality and for recruit-
ment rates derived from POSIM and those implied by our data. In 1976-77, for
example, a population of 40 adult males and 6 yearling males was estimated
through POSIM to be present on July 1, 1976. Our data indicated very low
hunter harvest and over-winter mortality of males during 1976-77. To arrive
at our spring population estimate of 24 adult males and 6 yearling males we
had to eliminate 16 individuals for which we had only limited data to support
mortality. This led us to believe that innaccurate data on population size
and composition for 1972 may have been used to initialize the POSIM program.
Other possible explanations include poor documentation and lack of under-
standing of male harvest rates; or inaccurate estimates of numbers of yearling
and adult males on the area in spring.

In May 1977, our data indicated a spring recruitment of 50 animals (presumably
25 females and 25 males) . This would have resulted in a population of 144
adult females and 55 adult males on July 1, 1977. To arrive at a population
of 116 adult females and 12 adult males estimated by our spring population
data, mortality rates would have had to occur that were significantly higher
than we documented. This indicated that either we over-estimated actual
recruitment in spring 1977 or under-estimated mortality during 1977-78. The
former, in our judgment, probably represents the best explanation for this
discrepancy. In this manner, POSIM was used to uncover weaknesses in our
understanding of certain aspects of Armstrong population dynamics.

Hunting mortality appeared to be lower in 1978 than the previous year (Table
17). In 1977, 60 percent of the marked bucks from the Armstrong range were
shot. Tag returns during the 1978 hunting season showed that 4 of 11 (36%)
marked males were killed. These Included one 2Js-year-old which died in mid-
November, evidently as a crippling loss. Three of the 11 (27%) marked males
which left the winter range in May 1978 and presumed to be alive during fall
were not accounted for during the winter. These may represent undocumented
mortality, or they may have spent the winter undetected on another winter
range. All three were young males. Thirty-six percent of the marked male
sample was known to be alive at the close of the hunting season. Seven other

Table I5, Aerial classifications of mule deer on the Armstrong winter range, January 1972 through March 1979.^

NUMBERS

RATIOS

PERCENTAGES

Total

Count

Total
Class .

Adults

Males

Females

Fawn

Unci .

F:100

Females

F:100 A

Males : 100
Females

% Fawn

% Ylg
Males

% Spike
Ylg Male

Reese Creek - 1971-72

Jan. 3

173

173

119

39

80

54

-

68

45

49

31

56

26

N. Cottonwood

Mar. 28

92

83

68

-

-

15

9

-

22

-

18

-

-

1972-73

Feb. 7

188

188

143

-

-

55

-

-

31

-

24

-

-

1973-74

Dec. 27

131

131

100

28

72

31

-

43

31

39

24

46

62

Apr. 1

188

188

154

-

-

34

-

-

22

-

18

-

-

1974-75

Jan. 5

140

140

116

37

79

24

-

30

21

47

17

19

17

Mar. 23

227

227

214

-

-

13

-

-

6

-

6

-

-

Apr. 20

99

99

96

-

-

3

-

-

3

-

3

“

-

1975-76

Jan. 2

121

121

113

29

84

8

-

10

7

35

7

7

100

Mar. 15

102

102

90

-

-

12

-

-

13

-

12

-

-

1976-77

Jan. 5-9

90

90

70

14

56

20

-

36

29

25

22

21

100

Mar. 10-11

116

116

81

-

-

29

-

-

33

-

25

-

-

1977-78

Dec. 19

133

133

94

11

83

39

-

47

42

13

29

46

40

Apr. 2

126

126

101

-

-

25

-

-

25

-

20

-

1978-79

Dec. 26

118

118

68

14

54

50

-

93

74

26

42

43

29

Mar. 12

98

98

68

-

-

30

-

-

44

31

■

^Includes some animals ranging between Bill Smith and Reese Creeks not Included in the Armstrong winter range population.

-EOT-

-104-

Table 16. Seasonal^and annual trends in the Armstrong mule deer population

Fawns

Ad. 99

Ad.cTcf

Yearlingijy

1972-73

July 1, 1972

184

150

60

30

(-106 U/

(-12)

(-23)

(-2)

Jan. 1, 1973

78

138

37

28

(-29)

(-15)

(-6)

(-1)

May 1, 1973

49

123

31

27

1973-74

May 1, 1973

193

147

58

25

(-134)

(-11)

(-27)

(-1)

Jan. 1, 1974

59

136

31

24

(-19)

(-6)

(-4)

(-1)

May 1, 1974

40

130

27

23

1974-75

July 1, 1974

206

150

50

20

(-163)

(-7)

(-8)

(-5)

Jan. 1, 1975

43

143

42

15

(-37)

(-30) .

(-7)

(-7)

May 1, 1975

6

113

35

8

1975-76

July 1, 1975

186

120

43

3

(-172)

(-2)

(-4)

(-0)

Jan. 1, 1976

14

118

39

3

(-2)

(-0)

(-2)

(-0)

May 1, 1976

12

118

37

3

1976-77

July 1, 1976

190

124

40

6

(-140)

(-0)

(-16)

(-0)

Jan. 1, 1977

50

124

24

6

(-0)

(-4)

(-0)

(-0)

May 1, 1977

50

120

24

6

1977-78

July 1, 1977

184

145

30

25

(-124)

(-2)

(-19)

(-19)

Jan. 1, 1978

60

143

11

6

(-28)

(-27)

(-5)

(-0)

May 1, 1978

32

116

6

6

1978-79

July 1, 1978

190

132

12

16

(-88)

(-2)

(-0)

(-2)

Jan. 1, 1979

102

130

12

14

(-83)

(-26)

(-6)

(-3)

May 1, 1979

It _ - ^

19

104

6

11

^Losses between time periods in parentheses.

Approximately 21 adult females that apparently wintered off the area in 1974-
75 were included in the spring estimate.

-105-

Table 17. Known hunting mortality of mule deer marked on the Armstrong
winter range, 1972-78.

Year

No.

Year

Killed

Marked

Marked

1972

1973

1974

1975

1976

1977

1978

Total

1972

5

1 (1%M)

l(2lsM)

0

0

l(5JsM)

0

0

3

1973

16

-

0

K7J5M)

0

0

0

0

1

1974

39

-

-

KlJ^M)

0

0

2 (4%M)
(1(HM)

0

3

1975

36

2(4igM)

(6JsF)

i(3hn)

4 (5%M)
(7%M)
(4J5M)
(7%M)

l(7isM)

8

1976

9

-

-

-

-

0

l(Ad.M)

0

1

1977

16

-

-

-

-

-

2(21sM)

(8^M)

0

2

1978

42

-

-

-

-

-

-

2(2hn)^^2

(2%M)

TOTALS

163

1

1

2

2

2

9

3

20

No . Markc
in Pop .-2^'

5

20

56/58

67/69

64/78

66/87

121109

% Shot

20.0

5.0

3.5

2.9

2.8

12.8

3.3

^An additional 2% year-old male marked in 1978 was a probable cripple loss
during the 1978 hunting season.

ry

1974-1978 - Known no. marked/total possible marked deer that could have
been present.

-106-

unmarked bucks were known to have been shot in the vicinity of the Armstrong
winter range during fall 1978. As in 1976-77, hunting was for males only,
except for 100 either-sex permits issued for National Forest lands within
Hunting District 312 which includes the Bridget Range.

The proportion of adult males in the Armstrong population has declined pro-
gressively from early winter 1974-75 to spring 1978 (Figure 10, Table 13).
Although numbers of males were still low in spring 1979, some Improvement
in yearling recruitment seemed evident. The four year trend has been influ-
enced greatly by low yearling recruitment, periodic over-winter mortality
of old adult males, and hunting losses of prime-aged adults throughout the
period, but especially in 1977. As shown in Figure 10, early winter numbers
of adult females also declined in 1978-79 after remaining relatively stable
from 1975-76 to 1977-78. This may be attributed to poor recruitment of
females during spring 1978, which failed to compensate for higher mortality
rates experienced by a predominantly old-age structured female segment. If
female recruitment fails to increase substantially in the next 2 years a
promounced decline in numbers of adult females can be expected.

Table 18 lists the distribution by age class of mule deer trapped on the
Armstrong range each year since 1972. Ages were assigned to the nearest year
when possible or to an age category on the basis of tooth replacement and wear
(Robinette et al. 1957). Mackle et al. 1978 indicated that life expectancy
of male mule deer in the Bridget Mountains appear to be only about two-thirds
as long as that of females (7-8 years vs. 10-12 years). The effects on popula-
tion trends and dynamics of variability in annual recruitment, as well as
differences in mortality rates and patterns was also discussed.

Age structural data for the 1979 winter-spring population (Table 18) indicate
that the young animals greatly predominated among males while old and very
old animals predominated in the female segment. Approximately 83 percent of
the adult males were 2% years of age or less. In contrast, 68 percent of the
adult females were older than 6^2 years and only 4 percent were aged as year-
lings.

Fawn Production and Survival

Aerial classification of deer on the Armstrong range during helicopter surveys
in late December 1978 and mid-March 1979 are listed in Table 15 together with
comparable data for previous years. The 93 fawns: 100 females and 74 fawns:

100 adults were the highest early winter ratios recorded since the study began
in January 1972. The 44 fawns; 100 adults observed in March 1979 was also
higher than any late winter ratio recorded in previous years. However, as
noted earlier, significant mortality of fawns occurred after mid-March. Much
less favorable results are obtained when the adjusted ratios are converted to
late spring fawns: female ratios and compared with previous years. Spring
population estimates show 40 fawns: 100 females in the spring of 1973, 31:100
in 1974, 5:100 in 1975, 10:100 in 1976, 42:100 in 1977, 27:100 in 1978, and
18:100 in 1979. In this light, survival to spring was lower than all other
years except 1975 and 1976.

Over-winter mortality of fawns during 1978-79 approached 80 percent. Mortality
during previous winters has ranged from little or none (1977) to 85-90 percent
(1975). The severe winter combined with a late spring green-up may have pre-
cipitated high total fawn loss. Aerial observations of radio-collared females
through August 1979 show a fawn: female ratio of 54:100 as compared to 113:100
for summer 1978. Then data may indicate lower fawn production and/or post-
partum survival during the current year.

Table 18. Mule deer population age structure on the Armstrong winter range as determined from deer
trapping samples, 1972-1979.

Numbers of deer

by age

category

Year

Sex

Total No.

h

1

2-5

6-7

8-10

10+

Unci. Ad.

M

4

4

1972

F

1

1

M

6

1

1

4

1973

F

12

1

9

2

M

12

4

2

3

1

2

1974

F

36

1

5

21

2

4

2

1

M

21

2

2

15

2

1975

F

29

2

17

4

3

3

M

15

10

2

1

2

1976

F

8

1

4

2

1

M

13

1

4

7

1

1977

F

20

1

12

5

2

M

18

10

4

2

1

1

1978

F

53

6

4

17

14

11

1

M

39

22

11

3

1

1

0

1

1979*

F

97

15

3

16

30

24

2

7

*Includes

observations that verify

presence

of deer

aged in

1978.

-107-

-108-

In utero production for 23 female mule deer collected in the Bridger
Mountains between 1973 and 1979 has averaged 139 fetuses per 100 females
2.5-years of age and older, and 100:100 for yearling females. Reproductive
data for individual females examined are listed in Appendix Table 21.

Although sample sizes are rather limited, these data suggest an overall
fetal rate somewhat lower than reported for mule deer on most other ranges
in Montana and elsewhere (Knowles 1977). When the potential for the Bridger
Range is compared with realized reproduction to early winter on the Armstrong
range from 1971-72 through 1978-79, substantial mortality between parturition
and early winter is evident and may be characteristic of this range and
population. Data on fawns in the population during summer and fall are
limited or lacking for most years. Pac (1976) found considerable fawn
mortality to occur in late fall during 1975.

During early winter 1978-79, 6 (43%) of 14 males observed during aerial
classifications were yearlings (Table 15). This compared with 5 (46%) of
11 males observed in late December 1979. While higher recruitment and
survival of yearlings through their first fall is indicated for the past two
years, yearling recruitment to and through the 1978-79 winter was relatively
low compared to 1973 and 1974. Fifteen yearling males were believed to occur
in the Armstrong population in early winter and 11 survived to April.

General Population Characteristics of Bridger Mountain Mule Deer, 1978-79.

Totals of 4,854 and 4,594 mule deer were classified throughout the Bridger
Range including the North 16-Mile area in early and late v^inter, respectively
(Table 19). These were the highest counts recorded for both periods since the sur-
veyswere Initiated in 1974-75, Early winter (Decem.ber) counts were up substantially
from the same period in 1977 on the east side (Battle Ridge, Brackett Creek
and Livingston) winter ranges as well as in the 16-Mile basin, while counts
were generally down on west slope ranges. Compared with counts for
previous years, these data suggested generally increasing populations on
the east side and in the 16-Mlle basin, while west slope numbers have re-
mained stable or declined since 1974-75.

The aerial counts underestimate actual numbers of deer present on winter
range, more so in early than in late winter (Mackie et al. 1978). In 1977-
78, data for the Intensively studies Armstrong area indicated sampling
efficiencies of about 47% and 59% for early and late winter. We believed
that these rates applied about equally to other west slope ranges, while
the efficiency of sampling on more open east side and 16-Mile ranges
probably was higher; perhaps 75%. On this basis, a total mule deer pop-
ulation of 4,500-5,000 was estimated for the entire Bridger Complex in early

winter 1977-78. Data obtained in 1978-79 suggested that this estimate may have
been too low.

For 1978-79, calculated sampling efficiencies for the Armstrong Range
were approximately 40% in early winter and 64% in late winter. For the same
time periods, Nyberg (In Prep.) estimated sampling efficiencies for the
Brackett Creek winter range as about 48% and 65%, respectively. Using
Armstrong data for the west slope and Brackett Creek data for the east
slope provides 1978-79 total population estimates of about 7,800 mule deer

Table 1 9. Numbers and sex and age ratios of mule deer classified by aerial (helicopter)
Mountain complex during early and late winter, 1971-72 through 1979-79.

survey on various winter ranges in the Bridget

1971

Earlv

-72

Late

1972-73
Earlv Late

1973

-74

No. Classif.

204

352

523

367

356’

NO. END

dtfUOO $

39.6

-

_

39.8

WEST SLOPE

FF:100 ?

62.3

-

38.3

_

FF:100 AD

44.6

29.9

32.7

27.4

19.0

No. Classif.

470

332

271

174

162

so. END

ciWUOO $9

39. 1

-

39.6

WEST SLOPE

FF:100

45.4

_

32.6

FF:100 AD

32.6

26.7

38.1

23.4

14.8

No. Classif.

_

_

BLACKTAIL

cW:iO0 ^

_

_

MOUNTAIN

FF:100 ^

-

-

_

_

_

FF: 100 AD

-

-

-

-

-

No. Classif.

_

SOUTH

cWtlOO ^

-

-

_

16-MILE

FF:100 $$

-

_

FF:100 AD

-

-

-

-

-

No. Classif.

_

NORTH

dWilOO

-

_

_

_

_

16-MILE

FFilOO ^

-

-

_

_

_

FF:100 AD

-

-

-

-

-

No. Classif.

_

BATTLE

dtf: 100 ??

-

_

_

RIDGE

FF:100 W

_

_

_

FF.-lOO AD

-

-

-

-

-

No. Classif.

_

BRACKETT

dW:100

-

_

_

CREEK

FF:100

-

-

_

_

_

FF:100 AD

-

-

-

-

-

No. Classif.

_

_

LIVINGSTON-

dtf:100

_

_

_

BILLMAN CR.

FF:100 ^

-

-

_

_

Ff:100 kb

-

-

-

-

-

No. Classif.

_

_

.

OTHER

db*: 150

_

_

-

_

MISCELLANEOUS

FF: 100 ^

-

-

_

_

_

AREAS

FF:100 AD

-

-

-

-

-

No. Classif.

674

684

794

541

518

BRIDGER

dWilOO

39.3

-

_

39.7

RANGE

FF:100 ¥$

50.3

_

36.4

TOTALS

FF: 100 AD

36.1

28.3

34.4

26. 1

18.5

1974-7i 1975-76 1976-77 1977-78 1978-79

Earlv

Late

Earlv

Late

Earlv

Late

Earlv

412

600

288

266

236

281

325

315

302

252

31.1

-

29.9

-

24.7

-

19.7

_

16.7

_

34.8

-

9.2

-

37.0

-

48.7

_

34.7

_

26.5

9.4

7.1

6.1

29.6

34.4

40.7

30.3

72.5

39.9

459

448

335

307

335

365

336

121

277

473

22.8

-

28.6

-

27.2

-

25.0

11.2

51.1

-

25.8

-

46.1

_

53.7

_

61.2

41.6

31.7

20.0

12.0

36.2

30.8

42.9

31.2

55.0

39.9

79

-

174

_

69

133

221

93

172

92

48.6

-

33.3

-

24.3

_

19.2

11.9

64.6

-

27.7

-

62.1

-

50.7

-

90.4

»

43.6

20.8

-

50.0

37.1

42.5

40.9

80.8

27.8

378

-

290

-

307

543

_

601

728

6.2

-

16.2

-

5.0

-

7.5

-

14.0

_

24.5

-

22.4

-

49.2

-

68.2

_

67.7

23.1

-

19.3

-

46.3

-

63.4

-

59.4

46.8

665

483+

766

725

814

831

910

1050

1267

1041

6.6

-

15.9

-

8.0

-

9.5

_

14.9

_

35.4

-

25.6

-

43.3

-

67.8

77.5

33.2

32.7

22.1

10.0

40.0

25.9

61.9

39.3

67.6

47.6

-

-

148

-

81

388

_

629

515

-

-

5.3

-

24.5

-

22.8

-

24.6

-

-

25.6

-

54.1

-

78.2

96.1

_

~

24.3

-

47.2

-

63.7

-

77.1

42.7

299

-

560

-

-

978

509

1120

1057

11.3

-

5.0

-

-

-

12.2

_

13.1

_

49.4

-

32.5

-

-

-

74.1

_

77.2

44.4

-

31.0

-

-

66.0

51.2

68.1

31.1

300

-

223

-

-

_

266

460

436

12.8

-

10.7

-

-

-

18.9

_

24.1

_

41.0

-

26.1

-

-

-

67.1

74.4

_

36.3

-

23.6

-

-

-

56.4

-

57.6

28.2

-

-

-

-

-

-

28

26

-

-

-

7.1

-

11.1

-

-

-

92.9

-

100.0

-

-

-

86.6

-

90.0

-

2592

1531

2784

1298

1842

1610

4060

2088

4854

4594

14.8

-

16.5

-

13.5

-

14.6

-

16.0

38.7

-

25.1

-

45.0

_

66.4

_

77.7

_

33.7

22.3

21.5

9.7

39.6

29.3

58.0

39.9

66.9

43.9

I

Not Including 100+ unclassified
■•■Northwest of 16-Mile Creek only

-601

-110-

for early winter and 5,500 for late winter. These estimates excluded the
North 16-Mile area, which is not considered part of the Bridger Complex.

These data indicate an approximate late December-mid March loss of about
29%, including 10-12% of all adults and 56-58% of all fawns present in
early winter. As indicated earlier, an estimated 40% of all deer present
on the Armstrong Range in early winter died, including about 8% of the
adults and up to 81% of the fawns. The Armstrong data, however. Included
additional losses which occurred in late March and April. Nyberg (in prep.)
estimated total losses on the Brackett Creek winter range at approximately
10% of all adults and 58% of all fawns for the December-March survey period,
but also noted additional losses of deer in late March and April. Because
of this, the estimate of 5,500 deer probably overestimates the number alive
in spring, and the 10-12% and 56-58% mortality rate for adults and fawns,
respectively, would also be minimal for the total Bridger Mountain mule
deer population. However, at this time we have no basis for believing
that very high total mortality rates experienced on the Armstrong area also
applied on other winter ranges, especially on the east slope and in the
16-Mile basin.

-III-

LITERATURE CITED

Bucsis, R. A. 1974. Ecological characteristics of the Armstrong mule deer
winter range, Bridger Mountains, Montana. Unpubl. Masters Thesis (M.
S.). Montana State University, Bozeman. 104 pp.

Clover, M. R. 1954. A portable trap and catch-net. Calif. Fish and Game
(40(4) :367-373.

Dietz, D. R. , R. H. Udall, H. R. Sheperd, and L. E. Yeager. 1958. Seasonal
progression in chemical content of five key browse species in Colorado.

: Proceed. Soc. of Amer. Foresters, Salt Lake City.

Hamlin, K. L. 1974. Ecological relationships of mule deer in the Bridger
Mountains, Montana, with special reference to daily and seasonal move-
ments. Unpubl. Masters Thesis (M.S.), Montana State University,

Bozeman. 65 pp.

Jorgensen, H. E. 1977. Habitat classification of Park and Prairie County
mule deer ranges. In: Statewide Habitat Research. Job Prog. Rept.,

Fed. Aid Proj. W-120-R-8, Study No. A-1.1. pp. 33-41.

Knowles, C. J. 1977. Statewide deer carcass collection. In: Montana Deer
Studies. Job Prog. Rept., Fed. Aid Proj. W-120-R-8. pp. 149-168.

Mackle, R. J., J. G. Mundinger, K. L. Hamlin and W. F. Schwarzkoph. 1975.

Use and effectiveness of four different trapping methods for mule
deer on winter range in the Bridger Mountains, Montana. Job Prog.

Rept., Montana Dept, of Fish and Game, Fed. Aid Proj. W-120-R. 9 pp.

Multilith.

, K. L. Hamlin, and J. G. Mundinger. 1976. Habitat relationships of

mule deer in the Bridger Mountains, Montana. Job Prog. Rept., Montana
Dept, of Fish and Game, Fed. Aid Proj. W-120-R— 6, Job No. BG-2.01
(Supplement). 46 pp. Multilith.

and C. J. Knowles. 1977. Population ecology and habitat relationships

of mule deer in the Bridger Mountains, Montana. Job Prog. Rept., Fed.
Aid Proj. W-120-R-8, Study BG-1.2, pp. 47-74, In: Montana Deeir Studies
1976-77. Montana Dept, of Fish and Game. 168 pp.

, D. F. Pac and H. E. Jorgensen. 1978. Population ecology and habitat

relationships of mule deer in the Bridger Mountains, Montana. In:

Montana Deer Studies. Job Prog. Rept., Fed. Aid Proj. W-120-R-9.

pp. 81-122.

McMannis, W. J. 1955. Geology of the Bridger Range, Montana. New York
Geological Society of America, Bull. Vol. 66:1385-1430.

Mooney, E. L. and T. N. Lonner. 1978. POSIM - A general wildlife population
simulator. Pp. 631-640. In: H. J. Higland, N. R. Neilson and L. G.

Hulls (eds.). Proc. 1978 Winter Simulation Conf., Miami, FL, Dec. 4-6,
1978. 1051 pp.

-112-

Morton^ M. A. 1976. Nutritional values of major mule deer winter forage
species in the Bridget Mountains, Montana. Unpubl. Masters Thesis
(M.S.), Montana State University, Bozeman. 104pp.

Nyberg, H. E, 1978. Distribution, movements, and habitat use of mule

deer associated with the Brackett Creek winter range, Bridget Mountains,
Montana. Jn: Montana Deer Studies. Job. Prog. Kept., Fed. Aid Proj .
W-120-R-9. pp. 133-139,

Overton, W. S, and D, E, Davis. 1969, Estimating the numbers of animals
in wildlife populations. P. 403-455, In: R. H. Giles (Ed.) Wildlife
Management Techniques, 3rd ed. Printed for The Wildlife Society by
Edwards Brothers, Inc, Ann Arbor, Michigan. 623 pp.

Pac , D, F, 1976. Distribution, movements and habitat use during spring,
summer and fall by mule deer associated with the Armstrong winter
range, Bridget Mountains, Montana. Unpubl. Thesis (M.S.), Montana
State University, Bozeman. 120, pp,

Payne, G. F. 1955, Native plants as sources of nutrients for grazing
animals. Proceeding Montana Academy of Science, 15:45-46,

Pfister, R. D,, B, L. Kovalchik, S, F. Arno, and R. C. Presby. 1977.

Forest habitat types of Montana. U.S.D.A. For. Serv. Gen. Tech, Rept.
INT-34, 174 p. Intermountain Forest and Range Experiment Station,

Ogden, Utah.

Picton, H. D, and R, R. Knight. 1969, A numerical index of winter condi-
tions of use in big game management. Proc. symp. on snow and ice in
relation to wildlife and recreation. Iowa State Univ. , Ames. pp. 29-38.

Robinette, W, L. , D. A. Jones, C. Rogers, and J. S. Gashwiler. 1957.

Notes on tooth development and wear for Rocky Mountain mule deer.

J, Wildl. Manage. 21 (2) : 134-153 .

Rosgaard, A. 1979. Habitat relations of mule deer associated with the

Brackett Creek winter range, Bridger Mountains, Montana. In: Montana
Deer Studies. Job Prog. Rept., Fed. Aid Proj. W-120-R-10, pp. 123-125.

Schwarzkoph, W, F. 1973. Range use and relationships of mule deer on the
west slope of the Bridger Mountains, Montana. Unpubl. Masters Thesis
(M.S.), Montana State University, Bozeman. 65 pp.

Steerey, W. F, 1979. Distribution, range use and population characteristics
of mule deer associated with the Schafer Creek winter range, Bridger
Mountains, Montana. Unpubl. Masters Thesis, Montana State University,
Bozeman. 119 pp.

Urness, P. J., D. J. Neff, and J. R, Vahle. 1975. Nutrient content of
mule deer diets from ponderosa pine range. J. Wildl. Manage. 39: (4)
670-673,

-113-

Wallmo, 0. C., L. H. Carpenter, W. L. Regelin, R. B. Gill and D. L. Baker.
1977. Evaluation of deer habitat on a nutritional basis. J. Range
Manage. 30(2) : 122-127 .

Williams, J. S. 1953. Seasonal trends of minerals and proteins in prairie
grasses. J. Range Manage. 6:100-108.

Youmans, H. B. B. 1979. Habitat use by mule deer of the Armstrong winter
range. Unpubl. Masters Thesis, Montana State University, Bozeman.

66 pp.

Submitted by: Richard J. Mackie

David F. Pac

Henry E. Jorgensen

-114-

Appendix Table

20.

List and current status of radio-collared deer on the
Armstrong range.

Radio
No .

Animal

No.

Sex

Age^

Date

Collared

Collar

Type

Trans .
Freq . ^

Remarks/ Status

1

14-73

F

3%+

2/10/73

Belt

M-4

AVM 1-8

Failed immediately
Recollared 1/21/79

2

7-74

F

Mat

4/16/74

Tygon

M-4

Failed? Never relocated

3

8-74

F

Mat

kiliyilk

Tygon

M-8

Failed - May 1974

4

3-72

F

6%+

3/6/75

Tygon

AVM 3

Failed - June 1978
Died Feb. 1979

5

34-74

F

Mat

3/29/75

Tygon

AVM 6

Winterkill - May 31, 1975

6

41-74

F

Mat

3/29/75

Tygon

AVM 1

Winterkill - May 2, 1975

7

16-75

F

2^5+

Tygon

AVM 8
AVM 2-3

Failed late July 1976
Recollared 1/29/78

8

17-75

F

3h+

4/10/75

Tygon

AVM 2

Failed mid-Aug. 1976

9

20-75

F

5%+

4/13/75

Tygon

AVM 11

Shot by hunter 10/29/75

10

27-75

F

3h+

kllkllb

Tygon

AVM 12

Winterkill - May 13, 1975

11

9-73

F

7h+

5ISI15

Tygon

AVM 6

Died Dec. 1977

12

1-76

M

5^2+

llllllh

Tygon

AVM 6

Died March 1978

13

2-76

M

6h+

2122116

Tygon

AVM 1

Failed late June 1976

14

2-72

M

2/25/76

Tygon

AVM 4

Shot by hunter 10/30/76

15

6/75

M

5h

2/27/76

2" PVC

AVM 2-8

Died Dec. 1977

16

1-75

F

ih

3/3/76

Tygon

AVM 11
AVM 1-2

AVM 2-9

OK when recollared on
1/24/78

Failed Jan. 1979
Recollared 2/27/79

17

1-73

F

4%

3/16/76

Tygon

AVM 5
AVM 1-7

Failed Dec. 1977
Recollared 1/10/78
Died March 1978

18

11-73

F

6%+

3/16/76

Tygon

AVM 10

Failed Dec. 1977
Died late March 1979

19

2-74

M

Mat

3/25/76

Tygon

AVM 7

Failed Nov. 1976
Shot by hunter 10/30/77

20

7-76

F

Mat

3/27/76

Tygon

AVM 9
AVM 1-4

Failed Jan. 1977
Recollared 1/23/78
Failed April 1979

21

1-77

F

Mat

1/31/77

1%" PVC

AVM 3

Failed June 1978

22

8-75

M

Mat

3/3/77

Tygon

AVM 8

Shot by hunter 11/26/77

23

19-74

F

Mat

3/5/77

2" PVC

AVM 1

OK through summer 1979

24

12-73

M

6I5

3/20/77

Tygon

AVM 7

Died March 1978

-115-

Appendix Table 20. (continued).

Radio

No.

Animal

No.

Sex

Age^

Date

Collared

Collar

Type

Trans .
Freq . ^

Remarks/ Status

25

4-77

F

8h+

8111111

ih"

PVC

AVM

2-5

Died April 1978

26

35-75

M

6^5+

klllll

Tygon

AVM

5

Died April/May 1977

27

1-78

F

6%+

1/21/78

1%"

PVC

AVM

1-12

Failed August 1979

28

7-78

M

1%

1/25/78

IJ2"

PVC

AVM

1-1

Died Nov. 1979

29

13-78

F

5h

8111118

Ih"

PVC

AVM

2-1

OK through summer

1979

30

20-78

F

5h+

2/4/78

ih"

PVC

AVM

2-4

OK through summer

1979

31

40-78

F

h

4/24/78

ih"

PVC

AVJI

1-7

OK through summer

1979

32

41-78

F

6^2+

4/24/78

ih"

PVC

AVM

2-5

OK through summer

1979

33

42-78

F

6^2+

4/24/78

ih"

PVC

AVM

1-11

Failed June 1978

34

31-75

F

7%

1/18/79

ih"

PVC

AVM

1-6

OK through summer

1979

35

51-79

M

2h

2/22/79

ih"

PVC

AVM

3-2

OK through summer

1979

36

55-79

M

8-9

2/24/79

Belt

Tel,

1-9

Died May 1979

37

56-79

F

Mat

2/24/79

Ih"

PVC

AVM

1-10

OK through summer

1979

38

69-79

F

7h

3/1/79

Ih"

PVC

AVM

2-8

OK through summer

1979

39

70-79

F

ih

3/2/79

Ih"

PVC

AVM

2-10

OK through summer

1979

^Estimated or known age when radio collar attached, several were radio-
equipped as recaptures of earlier collared deer; e.g.. No.'s 14-73, 3-72,
etc.

% = Markusen Electronics; AVM = AVM Electronics. AVM channels 1-12 as
designated for single band receiver. Other AVM channel designations are
from four band receiver.

Appendix Table 21. Reproductive sta

rom the Bridger Mountains.

laoie Zi. Keproductive stat

:us of 30 mule deer females from the Bridger Mountains.

Collection

D^te Location

Number Sex No. Corpora ^ Fetus Estimated

Age of of of Lutea of Crown-Rump Fetus

Female Fetuses Fetuses Pregnancy Conceptifn

4-16-73 Armstrong Winter Range

^ “ 1 26.8 589 Dec. 1

4-22-73 Armstrong Winter Range

^ F 31.5 941 Nov. 28

3-18-75 Armstrong Winter Range

^ F 2 23.0 336 Nov. 18

3-29-75 Armstrong Winter Range

^ ^ 2 23.5 399 Nov. 28

F' 23.0 424 Nov. 28

4-14-75* Armstrong Winter Range

FI 1 21.0 239 Dec. 22

5-3-75** Armstrong Winter Range

12 0 I 1 I ^

5-12-75 Armstrong Winter Range

2 F 2 30.0 796 Dec. 20

F- 29.0 731 Dec. 20

5-12-75 Armstrong Winter Range

^ 2 M 2 37.0 1,450 Dec. 1

^ 37.0 1,591 Dec. 1

5-14-75 Armstrong Winter Range

^ ^ FI 2 34.0 975 Dec. 10

34.0 791 Dec. 10

5-21-77 Schafer Cr. Winter Range

2 ^ 2 25.0 368 Nov. 14

F 24.5 395 Nov. 14

5—23—77 Schafer Cr. Winter Range

^ F" 2 28.0 649 Nov. 17

F 28.0 638 Nov. 17

June/1977 Schafer Cr. Winter Range

1

1

1

1

1

+

00

1-30-79 Armstrong Winter Range

1 « 1 5.3 - Dec. 6

-116-

Appendix Table 21. (continued).

Fetus

Humber

Sex

No. Corpora

Crown-Rump

Fetus

Estimated

Collection

Age of

of

of

Lutea of

Measurement

Weight

Date of

Date

Location Female

Fetuses

Fetuses

Pregnancy

(cms)

(gms)

Conception

1-31-78

Armstrong Winter Range

5%

1

M

2

11.5

-

Nov . 18

2-5-78

Armstrong Winter Range

Ih

1

M

1

4.0

-

Nov. 17

3-7-78

Armstrong Winter Range

8h

1

F

2

22.0

-

Nov . 17

3-15-78

Mouth of Bridget Canyon

2

M

F

—

20.0

Dec . 7

3-16-78

Bear Canyon

8

2

F

2

21.3

252

Nov. 30

F

21.4

278

Nov. 30

3-31-78

Brackett Cr. Winter Range

2

M

2

22.0

-

Dec. 11

F

22.8

-

Dec. 11

4-10-78

Brackett Cr. Winter Range

1

F

2

29.4

-

Nov. 27

4-20-78

Armstrong Winter Range

8h

1

F

1

20.5

-

Jan. 7

4-24-78

Armstrong Winter Range

ih

1

M

1

31.3

-

Dec. 8

2-13-79

Brackett Cr. Winter Range

10-12

1

F

2

10.2

30

Dec. 18

3-3-79

Brackett Cr. Winter Range

7h

1

F

3

15.5

101

Dec . 3

3-9-79

Battle Ridge Winter Range

ih

-

-

-

-

-

-

3-9-79

Brackett Cr. Winter Range

ih

1

M

2

15.0

83

Dec. 16

4-4-79

South 16-Mile Winter Range

3h

1

M

-

27.7

748

Dec . 1

4-4-79

"M" Winter Range

2h

1

M

1

23.5

410

Dec . 5

4-4-79

Jackson Creek

3h

2

F

3

25.5

-

Nov. 27

4-25-79

Brackett Cr, Winter Range

F

24.5

-

Nov. 27

ih

1

F

-

27.0

431

Dec. 25

*Fvidence of absorption of 1 fawn, 1 ovary atrophied.
**This doe had apparently aborted or resorbed its fetus.

117-

-119-

JOB TITLE: Habitat use by mule deer of the Armstrong winter range,

Bridger Mountains, Montana.

OBJECTIVES:

To determine the extent to which individual deer vary in their use of winter
habitats; and to evaluate the reliability of observational data in indicating
relative use and importance of various habitat types by mule deer during
winter .

FINDINGS:

Field work was completed during the spring of 1978 and the final thesis
report was submitted as a separate supplement to the 1977-78 Deer Studies
Report for Investigation of radio-marked mule deer on the Armstrong winter
range. An abstract of the thesis by Heidi B. B. Youmans is presented below.

ABSTRACT:

A study of winter habitat usage by mule deer was conducted on the Armstrong
winter range in the Bridger Mountains of southwestern Montana during the
winters of 1976-77 and 1977-78. Objectives were to ascertain the extent
of individual variability in habitat use and to evaluate the reliability
of conventional estimates of winter range use. A total of 19 deer wearing
radio transmitter collars were monitored from the ground, and from the air
during weekly surveys in a Supercub aircraft. Conventional ground observa-
tions were obtained of neckbanded and unmarked deer. The number of marked
deer on the winter range totaled 58 and 76 for the 1976-77 and 1977-78
winters, respectively. Relocations of instrumented and neckbanded indivi-
duals indicated the existence of three major winter range units. Instru-
mented animals exhibited larger home ranges during the first, mild winter
than during the second, more severe winter, and north unit deer were char-
acterized by more extensive movements than middle unit deer both winters.

A substantial bias toward open habitats in observations of neckbanded and
unmarked deer favored the use of instrumented deer for habitat use assess-
ment. During the 1976-77 winter, deer use was concentrated on the forested
upper portion of the winter range with only 19% of the total use by
instrumented deer occurring in shrub/grass types. Percent total use of
shrub/grass and forest types by instrumented deer during the 1977-78
winter was 39% and 54%, respectively. Core home range preference ratios
for individual habitat types and for shrub/grass and forest habitat categories
varied widely among individuals. But preference ratios less than 1 for total
shrub/grass types and greater than 1 for total forested types were common
to all instrumented individuals of the north and middle range units, indi-
cating a common preference for forested types. Habitat types most selected
were the JUSC-PUTR/FEID and PSME/FEID types of the north unit and the PSME/
SYAL and PSME/PRVI types of the middle unit. Temporal variation in habitat
usage and home range size during the 1977-78 winter reflected snow depth and
crust conditions. Snow depths of 36-48 cm with a nonsupportive surface
crust prompted deer congregation in forested habitats offering less severe
snow conditions. Habitat use patterns observed on the v^inter range
suggested a strategy of energy conservation rather than forage gathering.
Daytime deer activity reached a peak the first half of March, at the start
of accelerated snowmelt. Largest group size and greatest number of indivi-
duals sighted per observation period were recorded at that time.

-121-

JOB TITLE: Factors affecting deer populations in mountain-foothill

habitats of central and southwestern Montana (distribution,
range use and population characteristics of mule deer
associated with the Schafer Creek winter range, Bridger
Mountains, Montana).

OBJECTIVES:

To determine and describe seasonal habitats and habitat use of mule deer
associated with the Schafer Creek winter range; and to compare habitats,
habitat usage, and habitat relationships of mule deer on the Schafer Creek
Range with those of mule deer on the Armstrong Range.

FINDINGS:

Field work was completed during the spring of 1978 and the final thesis
report was submitted as a separate supplement to the 1977-78 Deer Studies^
Report for investigation on the population ecology and habitat relationships
of mule deer in the Schafer Creek winter range, Bridger Mountains, Montana.
An abstract of the thesis by William F. Steerey is presented below.

ABSTRACT:

A study was conducted in the Bridger Mountains of southwestern Mon-
tana from June 1976 through April 1978. Objectives were (1) to obtain
data on yearlong distribution, range use and population characteristics
of mule deer associated with the Schafer Creek winter range and (2) to
compare findings with those of earlier studies of deer associated with
the nearby Armstrong winter range. Vegetation of the Schafer Creek ^
study area was described as consisting of 5 habitat series, comprising
18 distinct habitat types. Series were: Idaho fescue with 2 habitat
types covering 1.7% of the area; big sagebrush with 2 habitat types cov-
2.6% of the area; Douglas fir with 7 habitat types covering 61.9% of the
area; subalpine fir with 5 habitat types covering 30.7% of the area and;
limber pine with 1 habitat type covering 2.9% of the area. Nine adult
females and 3 adult males were radio-collared and monitored from the
ground and 53 fixed-wing flights. An additional 17 mule deer were neck-
banded. Movement from the winter range by marked animals ranged from 0
to 29 km and averaged 4.8 km. Three holding areas were delineated on
two major travel corridors which were used by deer arriving on and de-
parting from the winter range. Associations among adult females appear-
ed to affect summer, fall and winter distributions. Home range size of
radio-collared deer was: 111 ha for females and 387 ha for males during
the mild winter of 1976-77; 178 ha for females and 152 ha for males
summer-early fall and; 58 ha for females during the more severe winter
of 1977-78. Three radioed deer summering in heavily forested habitats
had significantly smaller home ranges than 8 others of broken timber
habitats. Deer appeared to habitually use the same winter and summering
areas. Douglas fir habitats were the most important in winter, spring
and fall, and ranked second to subalpine fir in summer. Douglas fir/

Idaho fescue was the most used habitat type in winter while subalpine
fir/virgin's bower appeared to be the most important summer type. Closed
canopy habitats were important during spring and fall migrations.^ Fe-
males with fawns occurred with greater than expected frequencies in cer-

-122-

tain habitat types (PIFL/JUCO and PSME/FEID) during summer-early fall
but not during the 1977-78 winter. Forbs and browse were the most
important summer forage classes used while browse, grass and forbs, res-
pectively, were the most important winter forage classes. There was an
apparent 10-20% increase in population and an increase in fawn produc-
tion from the 1976-77 winter to 1977-78. Winter mortality was approxi-
mately 17-19% in 1976-77, consisting primarily of fawns, and was esti-
mated at a minimum of 15%, including 34% of all fawns in 1977-78. Noted
differences between the Schafer and Armstrong areas were: more Douglas
fir and subalpine fir habitats with shrub understories on the Schafer
summer area; no bitterbrush and much more Douglas f ir/snowberry habitats
on the Schafer Creek winter range and; smaller home ranges and generally
higher winter survival on the Schafer Creek winter range.

-123-

JOB TITLE: Distribution, movements and habitat use of mule deer

associated with the Brackett Creek winter range, Bridger
Mountains, Montana.

ABSTRACT: A study was initiated in January 1978 to determine the

movements, distribution and habitat use of mule deer
associated with the Brackett Creek winter range on the east
side of the Bridger Mountains. Findings are being prepared
in the final report.

OBJECTIVES:

To determine the movements, distribution and habitat use of mule deer
associated with the Brackett Creek winter range and compare the results
of this study with similar studies conducted on the Armstrong and Schafer
Creek winter ranges on the west slope of the Bridger Mountains and else-
where.

To prepare cover type and habitat type maps of the vegetation of the study
area.

To determine population characteristics of the Brackett Creek deer herd in
comparison with those of other mule deer populations in the Bridger
Mountains and elsewhere.

FINDINGS :

Field work continued through summer 1979 and winter-spring 1979. Data have
been compiled and analyzed, and the final job report will be com.pleted in
November 1980,

Submitted by:

Harvey E. Nyberg

-125-

Job Title:

Habitat relations of mule deer associated with the
Brackett Creek winter range.

Job Objectives: 1. To determine movements, distribution and habitat use

of the mule deer associated with the Brackett Creek
winter range and to compare results of this study with
results of similar studies conducted on the west
slope of the Bridger Mountains.

2. To quantify the vegetation of various habitat types
on the Brackett Creek winter range and compare these
data with results from studies on the west slope

of the Bridgers to determine whether a vegetation
factor is responsible for population density and home
range size differences between the two areas.

3. To determine public and hunter access and land use
practices on the Brackett Creek herd range in relation
to habitat use by mule deer.

INTRODUCTION

This study continues investigations initiated by Nyberg (1978, In prep.)
during the summer of 1978. This report summarizes the methods employed ^
and describes some results obtained from field studies during the summer
of 1979.

STUDY AREA

The Brackett Creek study area, located in the east-central portion of the
Bridger Mountain Range complex, has been described previously by Nyberg
(1978, In prep.). It consists of the northern half of Bangtail Ridge,
Brackett, Canyon and Bangtail Creek drainage to the Shields River. These
boundaries may be subject to some modification through further studies and
relocations of additional radio-collared and neckbanded deer.

METHODS

The distribution, movements and habitat use of mule deer associated with
the Brackett Creek winter range are being determined by relocation and
general observations of radio-collared, neckbanded and unmarked animals.
Relocation flights, using a fixed-wing aircraft, were conducted weekly
during June and July and biweekly in August and September 1979. Ground
observations, made in the course of vegetational studies on the winter
range or, during specific observation trips through the entire study area,
provided additional data.

Habitat and vegetative cover types on the Brackett Creek winter range were
delineated and mapped by Jorgenson (1977) and Nyberg {In prep.). During
the present study, vegetational characteristics of the various types will

-126-

be quantified using the point centered-quarter technique (Cottam and Curtis
1956) to determine tree-shrub densities and the canopy coverage method
(Daubenmire 1959) to estimate coverage of low shrub and herbaceous plants.

Information on hunting access, land ownership and land use practices will be
obtained from Park and Gallatin County and Gallatin National Forest records
and by interviewing landowners within and adjacent to the study area. Data
on hunter numbers, distribution and success and the harvest of mule deer from
the Brackett Creek population will be obtained using hunter questionnaires,
field surveys and bag checks during the hunting season, and returns of
tagged animals.

RESULTS

Field studies were initiated in mid-June, 1979. Emphasis was placed on
weekly and biweekly aerial relocations of radio-collared deer and on
vegetatlonal analyses. The relocations involved nine deer radio-collared
in 1978 and six equipped with transmitters in late winter 1979 (Table 1).

In general, the former exhibited the same dispersal pattern as observed
during 1978 (Nyberg 1978). One adult doe (Ch. 4/7.5), which could not
be relocated during the summer of 1978, was relocated in June 1979 and
subsequently spent the summer on Elkhorn Ridge, in the extreme northeast
corner of the Bridget Mountains, approximately 17 mi north of the study
area. However, the animal is no longer associated with the Brackett
Creek population, as it also spent the 1978-79 winter on the Battle Ridge
winter range, about 9 mi north of where it was originally trapped. All
but one of the 1979 radio-collared deer dispersed and established summer
home ranges within the general area used by deer in 1978. The exception,
a young adult male, moved approximately 5 mi north to the Antelope Creek
drainage along Battle Ridge, where it was later found dead. One other
instance of dispersal from the primary study area was recorded in the
recovery of a 2-year-old, neckbanded doe killed on Interstate Highway 90,

1 mi east of Bozeman and approximately 25 airline mi southeast of the
Brackett Creek winter range.

Field measurements associated with vegetatlonal analyses on the winter
range were completed by mid-September. Data will be compiled and analyzed
during the 1979-80 winter and summarized in the 1980 progress report.

LITERATURE CITED

Cottam, G. and J. T. Curtis. 1956. The use of distance measure in phyto-
sociological sampling. Ecology 37:451-460.

Daubenmire, R. F. 1959. A canopy coverage method of vegetatlonal analysis.
NW Science 33(1): 43-64.

Jorgensen, H. J. 1977. Habitat classification of Park and Prairie County
mule deer ranges. In: Statewide Habitat Research. Job Prog. Rept.,

Fed. Aid Proj . W-120-R-8, Study No. A-1.1. pp. 33-41.

Nyberg, H. E. 1978. Distribution, movements and habitat use of mule deer
associated with the Brackett Creek winter range, Bridger Mountains,
Montana. In: Montana Deer Studies. Job Prog. Rept., Fed. Aid Proi .
W-120-R-9. pp. 133-139.

Submitted by: A1 Rosgaard

-127-

Table 1.

Description of radio-

■collared deer

on the Brackett Creek range.

Channel

Sex

Age at
Trapping

Trap Site

Location of Summer Range

1978 Trapping

2/3.10

F

3%

Site E

Miles Creek

2/b.-i5

F

Site C

White Creek

2/9.35

F

4Js

Site D

Bangtail Creek

2/11.35

F

Adult

Site C

Ward Ranch

4/7.5

F

4%

Site A

(Relocated) Elkhorn Ridge

4/8.30

F

3is

Site E

Miles Creek

4/9.10

F

3%

Site B

Pehenpaugh Ranch (winter
range)

4/10.10

F

6^2

Site B

Stone Creek

4/12.15

F

bh

Site D

Miles Creek

1979 Trapping

3/11.25

M

ih

Site G

Canyon-Bangtail Cr. Divide
S. of Gobblers Knob

3/12.25

F

3Js

Site H

Miles Creek

4/2.20

M

3%

Site I

Antelope Creek (dead)

4/4.20

F

6^2

Site F

Miles Creek

4/5.20

F

3%

Site I

White Creek

4/6.20

F

4^2

Site I

Bangtail Creek

-129-

JOB TITLE Mule deer population ecology and habitat relationship in

the Missouri River Breaks, Montana.

ABSTRACT

An extremely severe winter in 1978-79 followed the almost equally severe
winter of 1977-78. Although some winter mortality of mule deer fawns
occurred, it was substantially less than that which occurred during the
relatively mild winter of 1975-76. Fawn production follov/ing both the
1977-78 and 1978-79 winters was excellent. As a result of this, the
mule deer population increased by almost 100% during 1978. Estimates
of initial fawn production in 1979 was 1.76 fawns/producing female, again,
near species potential. A sample of marked female m.ule deer indicated
that their initial fawn production was at least as high as that of the
population as a whole. Indicating no ill effects of the capture and marking
procedure. To date, a minimum of 73% of the known causes of summer
mortality of fawns was attributable to coyote predation. Percentage of
fall-winter deer mortality attributable to coyote predation has not been
reliably documented, however coyote predation was the major source of
documented mortality of females and fawns. During the last four years,
hunting mortality has been limited to adult males. Estimates of small
mammal population levels for 1976 through summer 1979 are presented.

These estimates indicate increasing small mammal populations through the
period, with the peak in rodent populations apparently occurring from fall
1978 through early Summer 1979. Mule deer fawn survival to December has
been positively associated with small mammal population levels, but
apparently not with coyote density. Baseline forage abundance data for five
habitat types during May, July and September are presented. Documentation
of the levels of sweetclover abundance during the last three years is
presented. A brief description of the movements and habitat use of the
deer during the two past severe winters is presented. Some preliminary
observations of home range establishment and social behavior of yearling
mule deer are presented. Information to date suggests that a poor forage
production year in 1971 followed by a severe winter in 1971-72 reduced
mule deer populations to a low level with no biological surplus. Subsequent
poor fawn survival and heavy either-sex hunting pressure further aggravated
this situation. As a result of low numbers of breeding female mule deer
and low small mammal populations during 1975-77, existing levels of coyote
predation appeared to be sufficient to impede recovery of the mule deer
population.

-130-

Job Title

Job Objective

Mule deer population ecology, habitat relationships,
and relations to livestock grazing management and
elk in the Missouri River Breaks, Montana.

To further determine the environmental requirements of
mule deer and factors regulating mule deer populations
in the "breaks" type of eastern Montana.

To further determine the direct and indirect effects
of livestock grazing management under rest-rotational
and continuous grazing systems upon deer populations
and habitat relationships and upon deer— elk inter-
relationship in the "breaks" type.

To develop new and improved guidelines for management
of mule deer populations and their habitats in the
"breaks" type of eastern Montana and for consideration
of deer habitat requirements in elk, livestock, and
range management programs in this type.

INTRODUCTION

In 1960, an intensive study of mule deer and their relationship to elk
(Cewus canadensis) and domestic livestock was established on a representa-
tive 75,000 acre area in the Missouri River Breaks approximately 25 miles
northeast of Roy, Montana. Habitat use and population studies were con-
ducted from June 1960 through September 1963 and intermittently from Oc-
tober 1963 through May 1964 (Mackie 1970). From the summer of 1964 through
spring 1975, less intensive studies were continued on the area primarily
to obtain population data for mule deer (Mackie 1976). Mackie (1970)
presented historical information on mule deer in the "Breaks", discussed
development of the existing population from the late 1930 ’s through the
early 1950 s, and described trends in numbers, sex and age composition
and harvest from 1960 through winter-spring 1964. Subsequent reports
(Mackie 1966, 1973 and 1976) extended these data through early winter

In July 1975, intensive studies resumed under the statewide deer
research program to further evaluate factors regulating mule deer popu-
lations in the breaks type habitat of eastern Montana.

A mule deer population decline on the study area, which started in winter
T971~72, continued to 1976—77 (Mackie 1976, Hamlin 1977). Population
declines have occurred on this area in the past, but recovery has gener-
ally started within a year or two of the decline. Low fawn production
and/or survival and ultimately low fawn recruitment was apparently the
problem involved in the continuing population decline of the mule deer
herd in recent years (Mackie 1976, Hamlin 1977). Low fawn ratios in some
prior years were associated with severe environmental conditions such as
drought in 1961-62 and severe winters in 1964-65 and 1971-72. However,
severe environmental conditions apparently cannot be implicated in the’
relatively low fawn production and/or survival during the years 1973-76.
From 1972 to 1976 normal precipitation during the growing season and mild,
open winters have been the general rule (Mackie 1976).

-131-

A preliminary report by Knowles (1976) indicated that coyote predation may
have been an important cause of mortality of mule deer, at least during
winter 1975-76. A graduate research project investigating mortality of
mule deer fawns from birth to September was initiated in June 1976. Dood
(1978) indicated that coyote predation was implicated in at least some
summer mortality of mule deer fawns on the south side Missouri River
Breaks study area.

Present work on the project emphasizes determination of fawn production
and survival, population dynamics of the herd and causes and timing of
mule deer mortality. Time constraints have precluded the analysis of much
of the data on basic deer biology that does not have apparent direct popu-
lation consequence. This information will be included in future reports.

ACKNOWLEDGEMENTS

The quantity and quality of data collected on this project has been greatly
enhanced by the superior flying and observational skills of Supercub pilot
Larry L. Schweitzer of Denton and helicopter pilot Murray Duffy of Bozeman.
Duane Pyrah has provided assistance and advice in all phases of the project.

Dick Mackie has provided assistance and advice in all phases of the project

and has provided unpublished data from the study area for 1960-1975. Shawn
Riley has provided invaluable assistance during three summers. Dr. Robert
Moore, Montana State University, is gratefully acknowledged for making
Sherman livetraps available during the summer. Many other Department or
former Department employees have provided valuable field assistance. The
study is being conducted in part on lands comprising the Charles M. Russell

Wildlife Range, administered by the U. S. Fish and Wildlife Service and in

part on lands administered by the Bureau of Land Management and the East
Indian Buttes Grazing District. The cooperation and assistance of these
agencies in some aspects of the study, including some financial support of
aerial surveys, is gratefully acknowledged, as is the assistance of many
Individual personnel. Numerous private landowners and ranchers on the
study area have also cooperated to assist the study effort through the years.

STUDY AREA

The south study area encompasses all of the timbered "breaks" portion
of the area described by Mackie (1970) as extending approximately 20
miles on a 4 to 7 mile wide belt adjacent to the Missouri River in
Fergus County, Montana (Fig. 1). It comprised approximately 100 square
miles between U.S. Highway 191 on the west, the Skyline Trail on the
east, the Missouri River on the north and the Musselshell Trail on the
south. Physiography, climate, land use and vegetation of this area were
described in detail by Mackie (1970) . Some of the work described in this
report was conducted on the adjacent Missouri River Bottomlands described
by Allen (1968) and NE across the river on the Nichols Coulee Resource
Conservation Area (north study area) described by Knowles (1975).

-132-

Figure 1. Map of the study area.

METHODS

Population data were obtained during fixed-wing surveys at various times
of the year and helicopter surveys during December and March. Sex and age
classifications and deer distribution and habitat use were obtained during
aerial surveys. Population estimates were made using data from helicopter
surveys in most years. During the last year, sufficient numbers of markef
deer were present on the study area to permit usage of the Lincoln Index
(Overtonand Davis 1969) for all aerial surveys. Supplementary information
was obtained throughout the year from the ground during the course of
normal activities.

Data on initial fawn production and subsequent fawn survival were obtained

/r ’reconnaissance. Survival was also measured by following
radio collared fawns. The river and reservoir ice was flown periodically
during winter to check for coyote-killed deer. The uplands were checked
for coyote-killed deer during aerial flights to relocate collared deer

on! activities. Carcasses are listed as probable

coyote kills based on evidence of tracks in the snow, trails of blood on
snow or vegetation and other site evidence.

Deer have been captured during winter in order to attach radio transmitters
et al. 1975), the Clover trap (Clover 1954), a helicopter drive net and

-133-

Aerial relocations of instrumented deer were obtained at 1 2 week intervals
and relocations from the ground were made as time permitted.

Data on hunting mortality and physical measurements of deer were obtained
from a check station on a major access road during the first weekend of
the season, from field checks of hunters throughout the season and from
voluntary hunter register boxes located along access roads.

Approximately 1 quart samples were obtained from rumens of deer killed by
hunters, coyotes and other undetermined causes for analysis of food habits.

Soil moisture readings were made at approximately two week intervals.

Thirty-two permanent transects totaling 320 2x5 dm plots were established
to determine year-to-year sweetclover abundance. Number of plants in each
plot and life phase are determined each year.

Five forage abundance transects totaling 100 2x5 dm plots each were established
and read during May, July and September on each of 5 habitat types . Browse
plants and green grasses were recorded as present or absent in each plot
while green forbs were recorded as number of plants per plot.

Following the graduate student study (Trout 1978) small mammal trapping has
continued in order to estimate yearly changes in abundance of alternate prey
species for predators. Snap trap lines utilizing Victor rat traps consist
of 20 stations approximately 15 meters apart with 2 traps per station. Snap
trap lines are run for three nights. The same livetrap lines utilized by
Trout (1978) are run each year with Sherman livetraps. The mice capture
are toe clipped so that they are individually recognizable. An attempt
is made to operate traps until few new mice are captured, thus giving an
estimate of total numbers. Headlight surveys to determine rabbit abundance
are run for three nights during each survey period.

WEATHER

Weather data for the period November through March and winter severity
indicies for the Roy 8NE weather station are presented in Table 1. Data
are not available for computing weather severity indicies P^ior to 1968 69.
Previously, the winter severity index of Picton and Knight (1969) was used.
It was felt that this index overemphasized the effect of minor snow depths,
so a new winter severity index was devised. The winter severity index was
calculated as follows:

_ — , No. days over clays over

Index = /40°F - (ave. winter temp .2/ + 12" of snoy^ . 18" of snow

10

+

These weather data Indicate that winter 1978-79 was slightly more severe
than 1977-78. Both winters were the most severe in many years. Winter
1978-79 had only slightly lower snow depths than 1977-78, but the lengt
of time that these extreme depths persisted was slightly longer in 19/« /y.
In addition, the average temperature for winter 1978-79 was significant y
colder than 1977-78.

Table 1 .

Winter severity indicies and climatological data, Roy 8 NE,
1968-1979.

November through March

Year

Average
Temp. (F)

Total

Snowfall

(inches)

Maximum

Depth

(inches)

No. Days
Snow on
Ground

No. Days
over 12
inches

No. Days
over 18
inches

Severity^

Index

1968-69

16.8

43

29

95

62

55

40.4

1969-70

26.8

32

9

49

0

0

13.2

1970-71

24.0

41

15

66

11

0

17.1

1971-72

21.7

62

28

114

71

44

34.2

1972-73

28.0

13

9

23

0

0

12.0

1973-74

27.5

25

6

57

0

0

12.5

1974-75

26.0

36

19

54

0

0

14.0

1975-76

29.3

42

9

51

5

0

11.2

1976-77

29.2

60

21

57

24

5

14.2

1977-78

19.0

86

56

128

108

90

49.8

1978-79

16.9

65

31

143

112

96

53.5

er numerical value indicates

greater severity.

-134-

-135-

Precipitation data were collected for two years on the study area from seven
rain gauges approximately three miles apart along an east-west line across
the study area. Data from these gauges and comparative data from adjacent
official weather stations are presented in Table 2. Monthly ranges of
precipitation often varied widely across the study area, but no consistent
pattern emerged. Cumulative average precipitation for these rain gauges
for the period April-October did not vary significantly from the cumulative
total for the Roy 8NE station (Table 2). The time and effort to continue
to monitor our gauges seemed unjustified and data collection ceased during
1979.

Table 2 . :

Recorded precipitation on
adjacent official weather

the study
recording

area compared with two
stations.

Month-Year

Number

Recording

Rain

Gauges

ppt.

Range

ppt.

Ave.

ppt.
Roy 8NE

ppt.

Mobridge

April 1977

6

0.13-0.27

0.19

0.20

0.17

May

7

2.14-3.49

2.67

2.66

2.62

June

6

1.11-1.97

1.57

1.58

1.27

July

7

1.13-2.73

1.49

2.35

1.99

August

4

2.12-2.40

2.29

2.42

2.21

September

6

2.40-2.86

2.77

2.14

2.62

October

6

0.18-0.40

0.29

0.64

0.45

TOTAL

11.27

11.99

11.33

April 1978

6

0.93-1.31

1.12

1.39

1.14

May

6

4.50-5.45

4.98

4.87

3.50

June

4

3.25-4.00

3.54

3.98

3.28

July

6

3.40-5.02

3.91

3.81

2.83

August

5

0.80-1.15

0.96

0.91

1.57

September

4

4.02-4.55

4.25

4.04

3.54

October

6

0.20-0.28

0.24

0.31

0.20

TOTAL

19.00

19.31

16.06

Similarly, two recording hydrothermographs were used to record temperatures
on the study area. Equipment malfunctions precluded gathering complete
data during most months. In those months with complete records, average
temperature varied less than one degree from the adjacent official weather
stations. The recording of temperature data ceased during 1979.

POPULATION TREND

South Study Area

Population data for mule deer on the study area from 1960-61 through 1978-79
are listed in Tables 3 and 4. Figure 2 extends Mackle's (1978) population
trend estimates through 1978-79. The population showed the first significant
upward trend in 7 years during 1978. High fawn survival up to and through
winter (Table 4) was associated with this upward trend. Population estimat-
ing techniques consistent with previous techniques placed the early winter

Table 3 • Sex and age composition of mule deer population on the Missouri Breaks Study Area,

1960-61 through 1978-79. Data were derived as aerial or ground classifications during
December or early January of each year except 1969-70 and 1972-73, when classifications
were completed during February and March, respectively.

Year

Type of
Observation

Number

Classi-

fied

Percentag

e

Males :
100 FF

Ratios
Fawns :
100 FF

Favms :
100 AD

% of Yrlg
Males

Males

Female

Fawns

Obsv.

Harv.

1960-61

Ground^

668

9.3

48.6

42.1

19.1

86.4

72.6

56

hi

1961-62

Ground

430

15.5

60.7

24.0

25.3

39.5

31.5

74

hi

1962-63

Ground

190

19.5

52.1

28.4

37.5

54.5

39.7

63

34

1963-64

Aerial^

362

16.0

45.6

38.4

35.1

84.2

63.3

itZ

36

1964-65

Aerial

611

22.7

47.8

29.5

47.6

61.6

41.7

ZZ

43

1965-66

Aerial

434

21.4

58.1

20.5

36.9

35.3

25.8

Z1

13

1966-67

Aerial

289

17.3

52.6

30.1

32.9

57.2

43.1

1967-68

Aerial^

115

20.0

40.0

40.0

50.0

100.0

66.7

—

1968-69

None

-

-

-

-

-

-

-

—

1969-70

Aerial

110

-

-

39.1

-

-

64.2

—

1970-71

Aerial

776

18.8

48.1

33.1

39.1

68.9

49.5

hi

1971-72

Aerial

679

19.0

53.8

27.2

26.1

50.6

37.4

1972-73

Aerial

235

-

-

19.1

-

-

23.7

—

1973-74

Aerial

370

24.1

49.5

26.5

48.6

53.6

36.0

hi

1974-75

Aerial

315

25.6

55.1

19.3

46.0

35.1

24.0

50

1975-76

Aerial

323

15.5

57.6

26.9

26.9

46.8

36.9

28

1976-77

Aer ial

258

17.4

57.4

25.2

30.4

43.9

33.6

40

1977-78

Aerial

322

10.9

58.7

30.4

18.5

51.9

43.8

48

1978-79

Aerial

501

13.2

42.3

44.5

31.1

105.2

3.2

55

^Cumulative observations on area during December.

^All aerial observations by helicopter except 1969-70 (fixed wing aircraft).
^Only west half of area surveyed in 1967-68.

-136-

Table 4 . Classifications and observed recruitment of fawns on the south side Missouri Breaks

study

area, 1975-76 through

197S-79.

Date

Total

Numbers

Adults

Young

Females

Males

Unci.

Fawns/

100

Adults

Fawns /
100 FF

Sept. -Oct. 1975

105

69

36

50

19

-

52

72

December 1975

323

236

87

186

50

-

37

47

March 1976

193

173

19

—

—

-

11

—

October 1976

159

no

49

79

31

-

45

62

December 1976

258

193

65

148

45

-

34

44

March 1977

293

225

68

—

—

-

30

—

October 1977

112

70

41

51

20

-

59

80

December 1977

322

224

98

189

35

-

44

52

March 1978

255

195

51

—

—

9

26

—

September 1978

176

102

74

69

33

-

73

107

December 1978

501

278

223

212

66

-

80

105

March 1979

409

248

161

—

—

-

65

—

-137-

Noo of deer per square mile

Figure 2. Population trend of mule deer

on the Missouri River Breaks study area, 1960-1978.

-139-

estimate at around 600 mule deer. This estimate is relative to previous
trend estimates and its precision has not yet been determined. Sufficient
numbers of marked deer were present during the last year to enable use of
the Lincoln Index (Overton and Davis 1969) in population estimation (Table
5), All population estimates derived by the Lincoln Index were higher
than those given by previous estimation and are striking in their consis-
tency. Results to date are preliminary, but continued usage of this
technique should help to make population estimates more precise.

Table 5. Population estimates of mule deer on the south Missouri River
Breaks study area.

Estimated No. Deer
On Study Area

Date

Remarks

732

Dec. 1978

Lincoln Index - helicopter survey

667

Mar-Apr 1979

X Lincoln Index - March helicopter
survey and April fixed-wing survey

639

March 1979

Based on December Lincoln Index
minus est. 5% adult mortality and
change in fawn/adult ratio

638

June 1979

Lincoln Index - fixed-wing survey-
new fawns not included

638

July 1979

Lincoln Index - fixed-wing survey-
new fawns not included

North Study Area

Population data for mule deer on the north study area from 1973-74 through
1978-79 are listed in Tables 6 and 7. The December survey was flown with
a fixed-wing aircraft rather than with a helicopter so numbers observed
are not directly comparable. If numbers of fawns that died overwinter
(based on change in ratios) is added to numbers observed during the March
helicopter flight, a minimum estimate can be made of 216 deer present in
early winter. This puts the north study area population at about the
same level as in early winter 1975, before the most recent decline. High
fawn survival was associated with this Increase.

Table 6. December population summaries for mule deer on the north study area, NCRCA^ .

Year

Total

Adults

Fawns

Females

Males

Yearlings

Mature

Fawns/100

Females

Fawns/100

Adults

Pastures

3 and 4

1973

184

134

50

100

34

18

16

50

37

1974

201

144

57

104

40

17

22

55

40

1975

208

172

36

119

53

19

34

30

21

1976

88^

63

25

42

11

1

6

60

40

1977

122

90

32

63

27

12

15

51

36

1978

1602

107

53

70

37

19

18

76

50

^Nichols

Coulee Resource

Conservation

Area.

^Total count not

obtained

in comparable manner

to other

years.

-140-

Table 7 .

the north side Missouri Breaks

Classifications and observed recruitment of fawns on
study area, 1975-76 through 1978-79.

Date

Total

No.

Adults

Young

Females

Males

Fawns/
100 Adults

Fawns/100

Females

Sept. -Oct. 1975

84

62

22

36

26

36

61

December 1975

208

172

36

119

53

21

30

March 1976

115

109

6

—

—

5.5

Sept. -Oct. 1976

65

48

17

29

19

35

59

December 1976

88

63

25

52

11

40

48

March 1977

118

92

26

—

—

28

October 1977

47

28

19

17

11

68

112

December 1977

122

90

32

63

27

36

51

March 1978

76

68

8

—

—

12

October 1978

86

60

26

34

26

43

76

January 1979

160

107

53

70

37

SO

76

March 1979

192

137

55

—

—

40

-142-

FAWN PRODUCTION AND SURVIVAL

Table 8 lists the known ratios of fawns/100 producing females and estimates
the ratios of fawns/100 females for the population as a whole in June and
mid-July 1976-1979. The estimate of fawns/100 producing females was obtained
from fawns observed with females during fawn capture and marking in June and
from those observed during aerial flights and ground observations in mid-
July. The ratios for June are minimum estimates since some fawn mortality
was known to have occurred during this period, at least in the first three
years. Also, information from radioed fawns indicates that, occasionally,
litters have been classified as singles when they were actually twins.

Table 8. Estimated mule deer fawn/female ratios in June and mid-July
1976-1979 on the south study area.

Fawns/100

Producing

Females

Percent

Females

Producing

Estimated
Population
Fawn/Doe ratio

June

1976

150:100(14)1

X

942

141:100

July

1976

131:100(16)

X

713

94:100

June

1977

152:100(27)

X

823

125:100

July

1977

140:100(20)

X

763

106:100

June

1978

165:100(26)

X

903

148:100

July

1978

142:100(31)

X

833

118:100

June

1979

176:100(37)

X

702

123:100

July

1979

171:100(35)

X

702

120:100

^Female sample size in parenthesis.

^Percent of female population older than yearling.
^Percent of females observed alone or with fawns.

Since no collections to determine iji utero productivity are made, the June
observations are the closest estimate of Initial productivity made on the
study area. It is felt that the variations in initial fawns/100 producing
females ratio (Table 8) is due to differing survival rates of fawns in the
first few weeks of life rather than due to differing in utero productivity
during the four years. The ratios of fawns/producing fem.ale observed on the
study area during June have equaled or exceeded ^ utero ratios of fetuses/
pregnant female in many other mule deer ranges and in some years are only
slightly lower than utero rates for other high quality mule deer ranges.

-143-

Table 9 lists the expected ratio of fawns/producing female at birth and
compares it to the observed ratio at capture. Since it is believed that
this herd is inherently a highly producing herd and that there are no
nutritional deficiencies (Hamlin 1978), near maximum estimates of in utero
productivity are used. Data are not available to compute age composition
of the female population in 1976. Although these mortality figures are
only estimates, they are believed to be reasonable.

Table 9. Expected fawn/producing female ratio at birth compared to
observed ratio at the time of fam tagging, 1977-1979.

Age of

„ ^ Fetuses

i ° Per

Female

No. Expected

Obs. fawns/

%

1-2 week

Female

Fetuses Fawns/Prod.

9

Prod .9 - June

Mortality

1977

ih

16

0

0

2h

5

1.3

7

3^5+

79

1.8

142

14%

84 prod . 99

149 fetuses 1.77

1.52

1978

ih

9

0

0

2h

14

1.3

18

3h+

77

1.8

139

5%

81 prod. 99

157 fetuses 1.73

1.65

1979

ih

30

0

0

2h

6

1.3

8

3^+

64

1.8

115

0%

70 prod . 99

123 fetuses 1.76

1.76

Mule deer females which were trapped and marked apparently suffered no ill
effects from the process. Twenty-eight of 36 marked females were observed
with fawns between 14 June and 12 September 1979. These observations are
spread throughout a normally high mortality period. Nevertheless, these
28 females produced a minimum of 52 fawns, including 7 singles, 18 sets of
twins and 3 sets of triplets. This provides a fawn/100 producing female
ratio of 186:100, even higher than the random sample of the population as
a whole. Twenty-one of these females were captured during the last winter
using the helicopter drive net. Of the 8 females not observed with fawns,

6 were not seen during the June-September period and 2 were observed only
once, both early in the season when fawns are seldom seen with the doe.

All of the marked does observed more than once had fawns, indicating that
the pregnancy rate of does older than yearling was lOO/o or near lOO/o during
1979.

-144-

Tables 10 and 11 show estimated and observed fawn/producing female ratios
and mortality rates for the south and north study areas, respectively during
the period June 1975 to March 1979. Time has not permitted obtaining June
fawn/producing female ratios for the north study area. During 1976 the ratio
was arbitrarily set as the same as that for the south study area. Since
that time, for comparative purposes, the ratios has been left the same as
that for the first year. This has probably led to an underestimate of the
total yearly mortality on the north area. The percent total fav/n mortality
for both study areas is also underestimated since the June ratio used is
survival to that point rather than the ratio at birth as outlined in Table
9. The patterns of survival have been the same on both study areas during
all years and the north study area has always had higher total mortality.
During the past year, the mid summer to December mortality rate was lower
than during any of the three previous years. December to March mortality
was fairly high, but not high enough to prevent high overall first year
survival. It is interesting to note that although survival to March was
near or only slightly below historical highs, about 50% of those fawns
born did not survive their first year.

The severe winter of 1977-78 apparently had little effect on fawn production
(Hamlin 1978). Winter 1978-79 was even more severe than 1977-78 (Table 1).
Although winter ended by the start of the last trimester of pregnancy, a
cool, dry spring resulted in little forage production until late May.

Initial fawn production again was near species' potential during 1979. As
discussed in last year's report (Hamlin 1978), it appears that the condition
of the deer going into winter has at least as much, and possibly even more,
impact on deer survival and subsequent fawn production than the severity
of the winter alone.

CAUSES OF MULE DEER MORTALITY

In an attempt to determine causes of summer fawn mortality, a graduate
research project using radio-telemetry to monitor and evaluate fawn
survival, was conducted during the summer of 1976 and 1977. During 1978
and 1979, these studies were continued by a summer student assistant.

Eleven, 19, 16 and 22 fawns were monitored during the four summers 1976—

1979, respectively. Table 12 presents the results of these investigations.
Nonradioed cohorts (i.e., nonradioed member of a set of twins) are
included in the fawns monitored column. Although natural abandonment
occurs, one facial each in 1978 and 1979 which appeared to have been abandoned
shortly after capture was not included in Table 12. Dood (1978) found 36%
and 32% fawn mortality during summer 1976 and 1977, respectively. S. Riley
(pers. comm.) found 13% and 14% fawn mortality during summer 1978 and 1979,
respectively. Eleven of 15 mortalities (73%) during the four summers were
definite or probable coyote-caused mortalities. No fawns that died exhibited
signs of poor condition prior to its death.

For the first year, in 1979, fawn radio transmitters lasted through the
winter. Twelve favms were monitored from September 1978 through March 1979.
One radioed fawn was illegally killed by a hunter during October 1978. Two
additional fawns were captured and marked in December. Three deaths occurred
during February. Site evidence indicated that all three were killed by
coyotes. The 23.1% mortality rate of marked fawns from December to March
closely approximates the estimated fawn mortality rate for the population
as a whole of 27% (Table 10).

-145-

Table 10. Fawn production and survival on the south Missouri Breaks
study area, 1975-76 through 1978-79.

Fawns Per 100 Percent

Initially Approximate Total Total

Producing Mortality Fawn Fawn

Females Rate Mortality Mortality

1975-76

Mid-June

150

Mid-July

—

October

83

35

22

December

54

70

28

March

16

1976-77

Mid-June

150

33

45

Mid- July

101

34

31

October

67

30

19

December

47

11

5

March

42

1977-78

Mid- June

152

15

20

Mid- July

129

24

27

October

98

36

31

December

63

40

22

March

38

1978-79

Mid-June

165

21

43

Mid-July

131

9

15

October

119

2

2

December

117

27

40

March

85

48%

-146-

Table 11. Fawn production and survival on the north Missouri River
Breaks study area, 1975-76 through 1978-79.

Fawns Per 100

Percent

Initially

Approximate

Total

Total

Producing

Mortality

Fawn

Fawn

Females

Rate

Mortality

Mortality

1975-76

June

150

52

56

October

72

51

26

December

34

71

18

March

10

93%

1976-77

June

150

59

77

October

61

18

10

December

50

30

13

March

35

77%

1977-78

June

150

17

20

October

132

52

49

December

60

67

31

March

20

87%

1978-79

June

150

45

81

October

83

0

0

December

83

20

19

March

66

56%

-147-

Table 12. Summer mortality and causes for marked mule deer fawns
1976-1979.

Year

No. 3

Marked

Fawns

No.

Died

%

Mort .

No. Definite
Or Probable
Coyote Killed

No.

Unknown

No.

Accident

%

Coyote

Killed

1976^

11

4

36

4

-

-

100

1977^

19

6

32

4

1

1

67

19783

15

2

13

1

1

-

50

19793

21

3

14

2

1

-

67

Total

66

15

23

11

3

1

73

^No. marked fawns column includes unmarked twin of radioed fawn
this situation occurred.

^Data from Dood (1978) and personal communication.

30ata from S. Riley (pers. comm.).

when

Overwinter adult mortality (Table 13) has been consistently low in spite
of the fact that the last two winters have been the most severe in at
least the last 20 years.

Table 13. Overwinter (Jan. -Mar.) mortality of marked adult mule deer
on the south Missouri River Breaks study area.

Year

No.

Marked

Deer

No .
Died

%

Mort .

No.

Marked

99

No.

Died

%

Mort .

No.

Marked

(fcf

No.

Died

%

Mort

1976-77

12

1

8.3

8

1

4

0

1977-78

19

1

5.3

14

1

5

0

1978-79

38

2

5.3

29

1

9

1

Total

69

4

5.8

51

3

5.9

18

1

5.6

-148-

Other than legal hunting mortality of adult males little is known of
recent causes of adult deer mortality. Two, 8 and 7 marked adult males
were available to hunters during 1976, 1977 and 1978, respectively.

One of the marked males was shot in each of the hunting seasons.

Although this represents an average annual hunting mortality rate of
184, the sample size is too small for confidence in its accuracy. One
radio-collared adult female was known to have been illegally shot during
September 1977 and one radio— collared adult female was a victim of coyote
predation during January 1977 . Additional known causes of mule deer
mortality has been confined to coyote predation during winter (Table 14).
Successively fewer coyote-killed deer have been found during winter in
spite of expanded effort to locate carcasses.

Table 14.

Probable coyote

-killed deer

found during winter

(December-March) ,

Uplands

Bottomlands

River

Ice

Reservoir

Ice

TOTAL

Mule Deer

1975-76

9

2

1

33

45

1976-77

4

0

3

9

16

1977-78

5

0

2

1

8

1978-79

3

0

1

1

5

White-tailed Deer
1975-76 1

10

9

0

20

1976-77

0

1

3

0

4

1977-78

0

1

0

0

1

1978-79

0

1

1

0

2

Known hunter harvest statistics to date for the hunting unit containing
the study area are listed in Table 15. Hunting mortality should have
been of negligible population consequence during the last four years
since only adult males could legally be harvested. During this period
of restrictive hunting seasons, only in the last year has the mule deer
population increased in spite of the fact that there has been no hunting
mortality of females and fawns.

Although hunting mortality should not have had any population impacts
during the period 1975-1978, it is quite possible that hunting mortality
during 1972-1974 aggravated the population decline and/or helped impede
its recovery. During winter 1971-72, severe winter mortality approximat-
ing 30% in adults and 85-30% in fawns occurred (Mackie 1976) . Prior

-149-

Table

15 . Mule deer
research

harvest statistics for HD 410
area.^

and the south

side

Mule

Deer

HD

Min. known Open, day ch
kill on HD 410

^ck sta.

Year

Bag

Limit

410^

Harvest

Hunters

research

area

Number

Hunters

Kill

1959

2-ES

5,117

5,084

1960

2-ES

5,769

6,486

150

407

129

1961

2-ES

5,951

7,091

151

224

70

1962

2-ES

5,964

6,482

81

350

70

1963

2-ES

6,683

5,925

37

89

37

1964

2-ES

6,800

6,860

73

117

55

1965

2-ES

2,945

3,680

141

26

1966

2-ES

. 4,086

4,468

1967

2-ES

2,603

3,587

1968

2-ES

3,061

4,031

1969

2-ES

3,102

3,399

1970

2-ES

3,271

3,774

1971

2-ES

4,245

7,351

1972

2-ES

3,050

7,385

1973

1-ES

1,689

5,847

1974

1-ES

1,531

5,614

1975

1-MM only

890

5,560

1976

1-MM only

738

2,742

7

48

4

1977

1-MM only

726

2,444

21

73

5

1978

1-MM only

688

2,961

10

36

2

^Point estimates for harvest from statewide hunter questionnaire.

( ^Data are for pre-1973 hunting district. HD 410 = present 410 + HD 417.

-150-

hunting patterns and population growth characteristics had probably
placed a substantial portion of the female population in the vulnerable
old age category (Mackie 1976). Thus, the population age structure
resulting after the severe winter probably consisted almost entirely
of prime— aged animals. Due to low fawn survival in subsequent years,
almost no biological surplus existed. A year of heavy hunting pressure
(2 deer - either sex) and high harvest and then 2 years of 1 deer - either
sex seasons followed the severe winter of 1971-72. Since almost no
biological surplus" existed, hunting mortality was primarily directed
toward prime-aged producing animals, further aggravating the population
decline .

ALTERNATE PREY RELATIONSHIPS TO DEER MORTALITY

Population trends of Peromysous manioulatus and various Microtine rodents
for the south study area from 1976-1979 as determined by snaptrapping
and livetrapplng are given in Figures 3, A, 5 and 6. Much of the data
for 1976 and 1977 are calculated from data in Trout (1978) . The equivalent
population trends for the north study area are given in Figure 7. These
figures indicate that 1978 was a peak year in PsvoTiTysous populations.
Populations remained high during summer 1979, but declined from 1978
levels. Microtine populations followed the same trend although they
remained high through early summer 1979.

Figure 3. Population levels of Peromysous manioulatus on the Artem.isia-

Agropyron grid on the south study area as determined by live-
trapping.

-151-

Cfl

3

3

O

3

n)

B

(0

3

U

Cfl

B

o

)-i

0)

m

o

o

z

I

5

Figure 4. Population levels of Peromysaus man.'tou'latus on the Savoobatus
grid on the south study area as determined by livetrapping .

-152-

7-79

L. curtatus

pennsylvanicus

JM. ochrogaster

60

Artemis ia-Agropyron grid

40 '

.

T “1 —

7-77 9-77 7-78 9-73

7-79 9-79

Figure 5. Population levels of Microtines on livetrap grids on the
south study area 1976-1979.

No. of mice/ 100 TN

30

20

Peromyscus maniculatus

Microtines

Figure 6. Population levels of mice on the south study area 1976-1979 as determined by snaptrapping .

-153-

-154-

Figure 7. Population levels of mice 1976-1979 on the north study area
as determined by snaptrapping.

Population trends for rabbits on the south study area are outlined in
Figures 8 and 9. Much of the data for 1976 and 1977 on the prairie
route are from Trout (1978). The drop in rabbit numbers during September
1978 may not be real since surveys had to be run during rainy, muddy
conditions at that time. The overall indications are that rabbit popu-
lations were higher during 1978 and 1979 than during the two previous
years. Population trends for rabbits on the north study area are out-
lined in Figure 10. Weather conditions were also bad on the north
study area at the time surveys were run in 1978. It is not believed
hov/ever, that rabbit populations were as high in 1978 as in 1977.

Figure 11 shows the estimated population levels of mice and rabbits on
the study area from 1960-1970. These estimates were made by using
written comments made by the staff of the Charles M. Russell Wildlife
Range in their annual narrative reports. In combination with current
information, this figure points out the probable cyclic nature of small
mammal population levels on the area.

The trend in total coyote numbers, including pups, on both study areas
as determined by siren survey (Pyrah 1977 , 1978) , indicated approximately
the same level in 1976 and 1978 with numbers slightly lower in 1977.
Observations of dens and marked and unmarked animals enabled estimates
of numbers of coyotes during 1977 and 1978. The adult coyote population
level remained about the same during 1977 and 1978 (Pyrah 1978) . Most

Total No. of jackrabbits

100

80

60

40

20

Figure 8 .

1976 1977 1978 1979

Population levels of jackrabbits on the prairie adjacent to the south study area as
determined by headlight surveys.

-155-

Total No. of rabbits

Figure 9, Population levels of jackrabbits and cottontails from the

breaks type headlight survey route on the south study area.

Figure 10, Population levels of jackrabbits and cottontails on the
north study area as determined by headlight surveys.

-157-

Estimated rabbit pop. level
Estimated mouse pop. level

O-

Figure 11. Estimated population levels of mice and rabbits on the study
area 1960-1970.

of the pups marked in the fall of 1978 are known to have dispersed from
the study area by spring 1979 (Pyrah pers. comm.). This occurred in spite
of the fact that small mammal population levels appeared adequate to
support many more coyotes than were present. Social factors and behavior
may have at least as much control over the base coyote population level
as food supplies (Pyrah pers. comm.).

The data indicate that mule deer fawn survival and recruitment has increased
as small mammal populations, particularly mice, have increased. During the
period of expanding small mammal populations, fawns survival did not appear
to have any relationship to the number of coyotes on the study area. It
might be argued that good forage conditions coincident with small mammal
highs also beneficially affected fawn survival. Most available small
mammal literature indicates that although the level of food may affect
the ultimate level of population highs it does not affect the timing of
the cycle. Hamlin (1978) indicated that the deer were in excellent physical
condition during periods of high coyote-caused fawn mortality, before the
recent excellent forage conditions. These factors seem to be indirect
evidence that at the previously existing mule deer population levels
coyote predation had an impact on fawn survival and recruitment and
ultimately the mule deer population level.

-158-

FORAGE CONDITIONS

Table 16 summarizes general impressions of forage conditions on the study
area from 1961 to the present. These forage conditions help give some
explanation for past mule deer population fluctuations and patterns of
fawn production and survival, Hamlin (1978) indicated that prior to the
1971 population crash, mule deer fawn survival to December appeared to be
highly correlated writh forage production.

Table 16. General impressions of forage conditions on the Missouri
Breaks study area 1961-1979.

Year Forage Conditions^

1961 Poor forage production, but fall green up of grasses

1962 Poor-ave. forage production early, but excellent late summer-

fall

1963 Excellent forage production, especially yellow sweetclover

1964 Good forage production

1965 Exceptional growth of grasses and browse

1966 Poor forage production

1967 Adequate forage production - stayed green throughout summer

1968 Good forage production - yellow sweetclover on parts of area-

fall green up

1969 Excellent forage production

1970 Good forage production

1971 Very poor forage production

1972 Excellent forage production - extensive 1st year sweetclover

1973 Extensive 2nd year sweetclover - fall green up

1974 Extensive 1st year sweetclover

1975 Extensive 2nd year sweetclover, but much grasshopper damage

by mid summer

1976 Poor forage production - also grasshopper damage

1977 Poor forage production, but fall green up

1978 Excellent forage production - extensive 1st year sweetclover

1979 Extensive 2nd year sweetclover, but dried up by August

^Impressions of forage production from R. J. Mackie field notes,

CMR annual narratives, BLM transects and photo plots and after 1975
from personal notes and impressions.

-159-

Yellow sweetclover {Melilotus offioionalis) has been documented as an
important forage source on the study area (Mackie 1970, Knowles 1975).
Since 1977 quantitative documentation of sweetclover abundance on the
study area has been attempted (Table 17). It is hoped that continuing
documentation of sweetclover abundance and availability will help in
interpretation of mule deer population dynamics on the study area.

Table

17 . Relative
area 1977

abundance of yellow
-1979.

sweetclover on

the south study

First Year

Sweetclover

Second Year

Sweetclover

Year

Total No.
Plants in
320 Plots

% Frequency
of Plants in
320 Plots

Total No.
Plants in
320 Plots

% Frequency
of Plants in
320 Plots

1977

11

1.9

0

0

1978

3229

43.1

21

3.4

1979

0

0

1407

38.1

Relative forage abundance on 5 habitat types is presented in Tables 18
and 19. This information should help to interpret the patterns of mule
deer distribution and habitat use. Table 20 presents soil moisture
conditions on the study area from 1976 through summer 1979. These data
should also be helpful in explaining patterns of mule deer distribution
and habitat use. Discussion of mule deer distribution and habitat use
in the Missouri River Breaks will be presented in future reports.

FOOD HABITS

Table 21 updates fall-winter mule deer food habits information for the
study area. Particularly noticable is that during fall 1978 the avail-
ability of yellow sweetclover resulted in its heavy use by mule deer.

The heavy use of sweetclover when it is available was previously docu-
mented by Mackie (1970) and Knowles (1975). Forage used during winter^
1978-79 as in 1977-78 probably reflects the extreme snow depth and limited
forage availability rather than the preferences of the deer.

Table 18.

Green forb abundance, excluding yellow sweetclover,
South Missouri River Breaks study area.

by vegetation type and season on the

MAY

JULY

SEPTEMBER

Vegetation Type

No.

100

of Plants per
2x5 dm Plots

% of

Total

Plants

No.

100

of Plants per
2x5 dm Plots

% of

Total

Plants

No. of Plants per
100 2x5 dm Plots

% of
Total

Artemisia-Agropyron

702

53%

348

36%

38

28%

Pseudo tsuga-Juniperus

207

16%

243

25%

54

39%

Pinus- Juniper us-
Agropyron

175

13%

252

26%

31

23%

Pinus- Juniperus-
shale

23

2%

57

6%

8

6%

Sarcobatus slopes

212

16%

70

7%

6

4%

Total Plants

1319

970

137

Percent of total
plants occurring
in each season

54%

40%

6%

-160-

-161-

Table 19. Percent frequency of occurrence of various shrub species in each
of five vegetation types.

VEGETATION TYPE

Shrub

Species

Artemisia-

Agropyron

(300)1

Pseudotsuga-

Juniperus

(300)

Pinus-

Juniperus-

Agropyron

(300)

Pinus-

Juniperus-

shale

(300)

Sarcobatus

slopes

(300)

Artemisia cana

1

tr.2

tr.

Artemisia

longifolia

1

6

Artemisia

tridentata

46

1

3

1

2

Atriplex nutalli

tr .

Chrysothamnus

nauseosus

tr .

1

Chrysothamnus
viscidif lorus

tr.

tr.

tr.

Eriogonum

multiceps

3

Guteriesia

sarothrae

3

Juniperus

scopulorum

57

5

17

tr .

Prunus

virginiana

12

1

Rhus trilobata

9

9

1

Ribes spp.

7

tr .

Rosa spp.

1

20

27

tr.

1

Sarcobatus

vermiculatus

1

39

Symphorocarpus spp.

50

18

1

’^Number of 2x5 dm plots in each type (20 plots on each of 15 sites),
^tr. = trace = less than 0.5 percent.

-162-

Table 20. Estimated soil moisture conditions on the south study area
1976-1979.

Date Soil Moisture Date Soil Moisture

Fell Below Est. Fell Below Est.

Wilting Point Wilting Point

Habitat Type -
Exposure

Depth

6"

1'

6"

1'

Artemisia-Agropyron

Year

ridgetop

1976

Aug.

1

Aug.

1

-

-

1977

July

15

June

5

late

Sept .

late Sept,

1978

Aug.

10

Aug.

1

Sept .

10

Sept. 10

1979

June

20

June

20

-

-

Pine-Juniper

north slope

1976

*

*

*

*

1977

Aug.

1

Aug.

1

-

-

1978

Aug.

20

Aug.

20

Sept .

10

-

1979

July

15

July

15

—

—

*Soil moisture did not fall below wilting point.

MOVEMENTS

The past two severe winters have resulted in the observation of marked and
unmarked deer moving in some cases up to 10 miles to winter in specific
topographical sites. Deer moved from drainage heads and other areas of
shallow relief to areas near the Missouri River. These wintering areas
almost always included a steep south— facing slope dominated by greasewood
(.ScLVOoho.'t'US V62wCc'uZ(Z'tus') and a steep north— facing slope with a FsBudoisucjcz—
Junipepus habitat type. The marked deer that moved to these areas during
winter 1977-78 and 1978-79 and for which information is available for the
mild winter of 1976-77 did not move to these sites during that winter.

Transmitters on 1 female and 5 male fawns radioed in June 1978 lasted through
at least late May 1979. This led to interesting observations of home range
establishment and social organization of mule deer. As previously observed,
during mid-to-late May, adult females seek solitude and are intolerant of
other deer including their previous year's fawns. By mid June, 4 of the 5
male fawns had moved from 3 to 13 airline miles from their previous home
ranges. After this time, either 3 of the 4 radios ceased to function or the
deer continued to move much further and radio contact was lost. One radio
has continued to function and this yearling male has apparently established
a new home range about 6 miles from the area it used as a fawn. One
yearling male has remained within its previous home range. The female fawn
was still on her previous home range at the time her transmitter ceased to

-163-

Table 21. Fall-winter food habits of mule deer on the south side Missouri
River Breaks, 1976-77 through 1978-79.

FALL

WINTER

Taxa

1976

(2)1

1977

(11)

1978

(8)

1976-77

(9)

1977-78

(5)

1978-79

(5)

GRASSES

tr?/50

37/100^

tr./13

tr./44

-

-

FORBS

Artemisia longifolia

4

-

5/50

8/44

-

2/60

Chrysopsis villosa

tr./27

-

—

Corapositae

-

—

—

tr. /II

Glycyrrhiza lepidota

-

-

tr. /25

—

Medicago sativa

-

1/9

—

—

Melilotus officionalis - tr./9

50/100

tr./ll

—

tr./20

Phlox hoodli

tr./9

-

—

—

—

Yucca glanca

tr./50

-

tr . /13

-

-

1/40

unid. forbs

10/50

1/45

tr . /13

XX. m

1/20

12/60

Total Forbs

10/100

3/64

55/100

9/44

1/20

15/80

BROWSE

Artemisia tridentata

-

-

-

13/89

19/100

22/100

Atriplex nutalli

-

-

-

4/44

11/40

-

Chrysothamnus spp.

67/100

20/82

tr . /13

37/100

7/20

2/20

Juniperus scopulorum

tr./50

2/36

-

18/100

17/100

29/100

Pinus ponderosa

tr./lOO

-

-

-

33/100

16/60

Pseudotsuga

tr./50

-

tr./ll

—

menziesii

Rhus trilobata

tr,/50

-

tr . /25

8/78

12/80

5/40

Rosa spp.

8/100

1/82

4/88

tr./33

-

3/20

Sarcobatus

-

-

-

-

-

6/20

vermiculatus

Symphorocarpos spp .

19/100

37/100

41/100

11/100

-

1/40

unid. browse

-

-

-

tr . /38

—

1/40

Total Browse

90/100

60/100

46/100

91/100

99/100

85/100

OTHER

Fungi

tr./18

tr./13

^No. of rumens.

^tr. = trace or less than 0.5 percent.

^Percent of diet by volume /percent frequency of occurrence.
“^May include some Eriogonum multiceps.

function shortly after 25 June. Additionally, information is available on 1
male and 2 female fawns marked during winter 1977. The male fawn was observed
with its mother until 23 May 1977, after which it was not observed again with
the female. On 28 October 1977, this male, now a yearling, was shot by a
hunter approximately 7 miles from its home range as a fawn. The two females
have, for 2^5 years, continued to occupy the same general home range area as
their mother. Between September and mid May of each subsequent year they have
often been observed with their mother in a group of deer. This social grouping
then breaks up in mid May, shortly before fawning and reforms again generally
during September.

-16A-

Discussion of factors influencing daily and seasonal movements and home range
size and use will be included in future reports.

DISCUSSION

The data available at present indicates the following conclusions:

1. A relatively high density deer population was severely reduced by winter
mortality (1971-72) following a summer of poor forage production.

2. Heavy either-sex hunting pressure on a deer population with no biological
surplus further aggravated the population decline during the period
1972-1974.

3. After 1974, hunting ceased to be a mortality factor for females and fawns.
However, due to continued low fawn survival, in spite of adequate forage
and mile winters, the population failed to increase.

4. During 1976-1979 coyote predation accounted for a minimum of 73% of the
documented summer fawn mortality. The precentage of fall-winter mule
deer mortality attributable to coyote predation was not reliably docu-
mented; however, coyote predation was the major source of documented
fall-winter deer mortality.

5. During 1976-1979, fawn survival rates appear to have been closely and
positively related to population levels of small mammals, but not to
coyote density.

6. When the population level of breeding females decreases to an as yet
undetermined threshold, any source of favm mortality, including coyote
predation, can have substantial population impacts. The threshold of
impact probably depends on the mortality rate of adult females.

7. Myriad factors affect deer populations. liHien these factors act con-
currently or consecutively, deer population levels can be substantially
altered.

8. In view of the anticipated low levels of rodent populations during
summer 1980, it is recommended that the monitoring of small mammal
populations and coyote density continue through at least summer 1980.

If coyote predation on mule deer Increases because of low small mammal
population, its effect on a mule deer population that could be up to
three times its previous density should be documented.

It is anticipated that future reports will contain more infomation and

discussion of estimation of mule deer numbers, basic mule deer ecology

in the river breaks type, competition and comparisons with other mule deer

studies throughout the state.

-165-

literature CITED

Allen, E. 0. 1968. Range use, foods, condition and productivity of white-

tailed deer in Montana. J. Wildl. Manage. 32 (1) : 130— 141.

Clover, M. R. 1954. A portable trap and catch net. Calif. Fish and Game.
40(4): 367-373.

Dood. A. R. 1978. Summer movements, habitat use, and mortality of mule
deer fawns in the Missouri River Breaks, Montana. Montana Job Compl.
Rept., Proj. W-120-R-8, 9. Job No. 9. 55pp.

Hamlin, K. L. 1977. Mule deer population ecology, habitat relationships,
and relations to livestock grazing management and elk in the Missouri
River Breaks, Montana. In: Montana Deer Studies, Job Prog. Rept.,

Proj. W— 120— R— 8. Job 3. pp. 84—104.

. 1978. Mule deer population ecology, habiat relationships, and

relations to livestock grazing management and elk in the Missouri
River Breaks, Montana. In: Montana Deer Studies. Job Prog. Rept.,

Proj. W— 120— R-9. Job 3. pp. 141-176.

Knowles, C. J. 1975. Range relationships of mule deer, elk and cattle in
a rest-rotation grazing system during summer and fall. Unpubl. M. S.
Thesis, Montana State Univ. , Bozeman. 111pp.

. 1976. Observations of coyote predation on mule deer and white-tailed

deer in the Missouri River Breaks, 1975-76. In: Montana Deer Studies.

Job Prog. Rept., Proj. W-120-R-7. pp. 117-138.

Mackie, R. J. 1966. Some phenomena associated with dynamics of mule deer
in the Missouri River Breaks of Montana. Proc. West. Assoc. St. Game
Fish Comm. 46:129-133.

. 1970. Range ecology and relations of mule deer, elk, and cattle

in the Missouri River Breaks, Montana. Wildl. Monogr. No. 20. 79 pp.

. 1973. What we've learned about our most popular game animal. Mont.
Outdoors. 4(5):15-21.

, J. G. Mundinger, K. L. Hamlin and W. F. Schwarzkoph. 1975. Use and
effectiveness of four different trapping methods for mule deer on winter
range in the Bridger Mountains, Montana. Job Prog. Rept., Montana Dept,
of Fish and Game, Fed. Aid Proj. W-120-R. 9pp. Multilith.

1976. Mule deer population ecology, habitat relationships, and
relations to livestock grazing management and elk in the Missouri River
Breaks, Montana. In: Montana Deer Studies. Job. Prog. Rept., Proj.
W-120-R-7. pp. 67-94.

Overton, W. S. and D. E. Davis. 1969. Estimating the numbers of animals
in wildlife populations, pp. 403-455. In: R. H. Giles (Editor).
Wildlife Management Techniques. 3rd Ed. Edwards Brothers, Inc., Ann
Arbor, Michigan. 623 pp.

-166-

Picton, H. D. and R. R. Knight. 1969. A numerical index of winter conditions
of use in big game management. Proc. symp. on snow and ice in relation to
wildlife and recreation. Iowa State Univ. Ames. pp. 29-33.

Pyrah, D. B. 1977. The effects of coyotes on mule deer production in the

Missouri Breaks. 7n: Montana Deer Studies. Job Prog. Rept., Pro j . W-120-
R-8. pp. 115-129.

. 1978. The effect of coyotes on mule deer production in the Missouri

Breaks, pp. 23-45. Ini Effects of coyote predation on big game populations
in Montana. Job Prog. Rept. W-120-R-9. 49pp.

Trout, R. G. 1978. Small mammal abundance and distribution in the Missouri
River Breaks, Montana. Unpubl. M. S. Thesis. Montana State Univ.,

Bozeman. 64pp.

Submitted by:

Kenneth L. Hamlin

-167-

job TITLE: Population ecology and habitat relationships of white-tailed

deer on bottomlands of the Missouri River in northcentral
Montana.

ABSTRACT :

Limited information was collected on a white-tailed deer population
on the Missouri River bottomlands of northcentral Montana. Population
estimates for 1978-79 ranged from 123 to 172 white-tailed deer on the study
area. A minimum density^estimate was 15.6 deer/ml comparing to a minimum
estimate of 29.5 deer/mi in 1971-72. Fixed-wing aerial surveys are apparently
as effective as helicopter surveys in estimating total numbers of white-
tailed deer on the Missouri River bottomlands. Severe spring flooding
again disrupted normal habitat use patterns. Permanent raises of the water
level of Fort Peck Reservoir have destroyed about 4.5 mi^ of white-tailed
deer habitat since 1964.

5

-168-

JOB TITLE: Population ecology and habitat relationships of white-tailed

deer on bottomlands of the Missouri River in northcentral
Montana, 1977-78.

JOB OBJECTIVE: To determine the environmental requirements of white-

tailed deer and factors regulating whitetail population
in major river bottom habitats of northcentral Montana.

To determine the effects of various potentially competing
land use and management practices upon white-tailed deer
in northcentral Montana.

To develop new and improved guidelines for management of
northcentral Montana whitetail populations and their habi-
tats.

INTRODUCTION:

Few data are available on the population ecology and environmental require-
ments of white-tailed deer {Odoooileus virginiana) populations associated
with the floodplains of major rivers in Montana. The only existing study
(Allen 1968) was conducted in 1964-65 and primarily concerned range use,
food habits, condition and productivity of white-tailed deer on bottomlands
of the Missouri River in northcentral Montana.

To meet the need for further Information concerning white-tailed deer in
river bottom habitats, this study was established during 1975 on the same
area on which Allen's (1968) study was conducted. Field studies were ini-
tiated during early winter 1975-76 and preliminary findings have been
reported by Mackie and Knowles (1976) and Hamlin (1977 and 1978). Due to other
work demands, field studies have not been intensive and were confined primarily
to obtaining population data and deer distribution.

STUDY AREA

The study area is located on the Charles M. Russell Wildlife Refuge, ad-
ministered by the U. S. Department of Interior Fish and Wildlife Service.
The study area consisted of 20 bottoms and 3 islands included in a straight
line distance of about 23 miles (Fig. 1). The floodplain varied from to
1 mile in width and bottoms, ranging in size from 144 to 644 acres, usually
alternated between north and south sides of the river. The ridges over-
looking the river are at approximately 2,900 feet elevation and slope at a
relatively steep angle to the floodplain at approximately 2,270 feet.

Physiography, climate, land usage and vegetation of this area have been
described in detail by Allen (1968). Mackie (1970) and Knowles (1975)
provide similar information for adjacent uplands.

-169-

Figure 1. Map of study area.

METHODS

Existing data from prior management surveys and research studies on white-
tailed deer on Missouri River bottoms of the study area were reviewed,
analyzed and Incorporated into the present report when applicable.

An early winter aerial survey, employing a helicopter, was conducted on
10 December 1978, to count and classify whitetalls on the study area.

During February, four different white-tailed deer were captured with Clover
traps (Clover 1954) on bottom 4 (Fig. 1). Two were fitted with radio trans-
mitters and two with individual observation collars of Armortite fabric.
Deer collared during previous winters were also available for observation.

Periodic ground and aerial (Piper Supercub) observations were made through-
out the year to determine movements, distribution, mortality and survival
of white-tailed deer.

RESULTS

Population Studies

In spite of the previous severe winter and March flooding of the bottoms,
fawn/ female and fawn/adult ratios reached their highest recorded level
since 1971-72 (Table 1). These ratios, a noticeable improvement over
the previous 4 years, are still substantially below species potential.

The 90 white-tailed deer observed during the helicopter survey was an
underestimate of the total number present. A minimum estimate of the white-
tailed deer present would be the 116 observed on a fixed-wing flight on
8 January 1979 plus seven marked deer present, but not observed (123 total).
In addition to the marked deer missed, there were undoubtedly some un-
marked deer missed on that flight. The average of three Lincoln indicies
calculated from surveys conducted on 21 November 19/o, 10 December 1978 and
8 January 1979 was 172 white-tailed deer (range 120-206).

Table 1. White tailed deer numbers, sex and age composition from early winter surveys 1960-1976.

Year

Numbers

Rat ios

Tot.

AD

YG

Fern.

Males^

Yrlg

Mat-

ure

YG:100

AD

YG:100

FF

% YG

MM: 100
FF

% YG
MM

1973-742

207

168

39

146

22

9

13

23.2

26.7

18.8

15.1

40.9

1975-762

121

105

16

76

29

8

21

15.2

21.0

13.2

38.2

27.6

1976-772

18

15

3

10

5

2

3

20.0

30.0

16.6

50.0

66.7

1977-782

110

96

14

58

38

17

21

14.6

24.1

12.7

65.5

44.7

1978-/92

90

69

21

53

16

7

9

30.4

39.6

23.3

30.2

43.8

^Includes unclassified males.

2

Helicopter survey. Complete coverage.

-170-

-171-

It appears that the helicopter survey could be discontinued without
adversely affecting population estimates. During 1977-78, 110 white-
tailed deer were counted from the helicopter. Subsequent fixed-wing
flights resulted in counts of 90, 107 and 99 deer. During 1978-79, 90
white-tailed deer were counted from the helicopter whereas fixed-wing
flights resulted in counts of 116, 105 and 97 deer.

Distribution and Movements

Severe flooding of all bottoms again occurred in March 1979, duplicating
effects of flooding in March 1978. This type of flooding occurs when
there is heavy winter snowfall with rapid spring runoff occurring before
the river ice has broken up.

Although winter-spring distribution of white-tailed deer has remained
relatively constant on a unit basis (Table 2) over the last 3 years,
distribution on individual bottoms has fluctuated. Reasons for the changing
winter use patterns of individual bottoms have not been determined. Limited
information from individually marked deer indicates that this shifting
distribution has occurred for individual animals as well as for the pop-
ulation as a whole. The tendency has been for those bottoms further upstream
to receive increasing use each succeeding year. Units are delineated on the
basis of severity and frequency of flooding, rather than as population units.
Only deer wintering in the middle unit have been captured and marked to this
time. Their summer-fall distribution includes bottoms in all three units.

Information on movements of individual white-tailed deer is limited at
this time. Further available information is complicated by spring flooding
for the last 2 years. Analysis of movements data will be presented when
more relocations have been obtained.

DISCUSSION

A more permanent and regular flooding of some river bottoms occurs because
of the rising levels of Fort Peck Reservoir. Major raises of the water
levels of the reservoir occurred in 1964-65 and 1975 (Table 3). Although
the precise elevations of each of the bottoms is unknown. Bottoms No. 12-20
have all or significant portions of their white-tailed deer habitat below
2,250 ft elevation. Therefore, all of these bottoms have been subject to
spring-summer flooding since at least 1975. Bottoms No. 16-20 have been
subject to total or partial permanent flooding since 1965.

Originally there were about 7,890 A (12.3 mi^) of habitat available for
white-tailed deer on the study area. Permanent and periodic flooding is
estimated to have destroyed about 2,850 A (4.5 mi^) , or about 36 percent of
the available habitat. On a strictly habitat -available-basis , only about
64 percent of pre-1964-65 population levels might be expected today. About
53 percent (Table 2) of the deer spent winter and early spring prior to 1965
on bottoms subsequently subjected to permanent and/or periodic severe flood-
ing. This could mean that no more than about 47 percent of the pre-1964-65
population levels could be expected at present in the remaining habitat.
Population data are available for only one year prior to the 1964-65 rise in the

Table 2. White-tailed deer distribution during winter

and spring, 196A-77, listed by percent of total

per Bottom, Island or Unit.

Winter-Spring

1964-65

717

3

Tr 1

Winter

1971-72

267

3

4

Winter

1973-74

207

4

4

Wint er
1975-76

121

18

7

Winter- Spring
1976-77

131

16

24

Winter

1978

406

25

1 15

Winter

]d7R-79

494

28

10

Upper Unit

Winter-Spring

1964-65

717

8

Wint er
1971-72

267

7

Winter

1973-74

207

13

Wint er
1975-76

121

25

Winter-Spring

1976-77

131

40

Winter

1978

406

41

Winter

1978-79

494

38

4

—

3

1

2

3

26

1

Tr

2

Tr

9

9

8

3

-

17

6

5

-

4

4

4

46

2

-

-

-

-

10

-

44

12

-

-

-

12

-

-

7

-

2

18

4

11

-

25

1

-

-

15

-

13

17

4

-

5

-

-

4

14

4

22

13

-

1

5

2

_

Tr

Middle Unit
36

51

56

68

61

54

61

- Tr Tr 7 26 11 2 4

- 15 - 20 Tr

-19-3--__

Tr Tr - - _ _ _ _

Lower Unit
56

35

32

7

0

5

1

t

hJ

I

-17 3-

Table 3.

Maximum elevational levels of
Reservoir (MSL) , 1959-1978.

surface water of

Fort Peck

Year

Elevation

Year

Elevation

1959

2209.9

1969

2246.4

1960^

2217.7

1970

2247.0

1961

2209.0

1971

2243.6

1962

2202.6

1972

2243.8

1963

2216.0

1973

2241.7

19642

2235.7

1974

2244.5

1965

2245.6

19753

2251.6

1966

2242.1

1976

2249.0

1967

2245.4

1977

2239.7

1968

2244.4

1978

2249.2

^Maximum elevation prior to 1964-65.

^Reservoir level started rising in June 1964 and continued until August 1965.
^July 1975 represents the 2nd major raising of the reservoir level.

-174-

water level, so It IS difficult to make a numerical population impact
assessment for the- first permanent raising of the reservoir's surface level.

During winter 1971-72, when an estimated 5,795 A (9.05 mi^) of habitat were
available, 267 deer were seen during the helicipter survey. This gives a
minimum density estimate of 29.5 deer /mi which is quite similar to the
30.5 deer/mi2 estimated by Swenson (1978) for the Yellowstone River Bottom
near Intake. A minimum estimate for the 7.85 mi2 of habitat estimated
available in 1978-79 is about 15.6 deer/mi2, or about one-half of the
1971-72 density estimate.

LITERATURE CITED

Allen, E. 0. 1968. Range use, foods, conditions and productivity of white-

tailed deer in Montana. J. Wildl. Manage. 32 (1) :130-141.

Clover, M. R. 1954. A portable trap and catch-net. California Fish and
Game. 40(4) :367-373.

Hamlin, K. L. 1977. Population ecology and habitat relationships of white-
tailed deer on bottomlands of the Missouri River in northcentral
Montana. Pp. 105-113. In: Montana Deer Studies. Job Progress Report.
Montana Dept, of Fish and Game, Fed. Aid Proj . W-120-R-8.

Hamlin, K. L. 1978. Population ecology and habitat relationships of white-
tailed deer on bottomlands of the Missouri River in northcentral
Montana. Pp. 177-183. In: Montana Deer Studies. Job Progress Rept .
Montana Dept, of Fish and Game, Fed. Aid Proj. W-120-R-9.

Knowles, C. J. 1975. Range relationships of mule deer, elk and cattle in
a rest-rotation grazing system during summer and fall. M. S. Thesis.
Montana State Univ. , Bozeman, MT. Ill pp.

Mackie, R. J. 1970. Range ecology and relations of mule deer, elk and

cattle in the Missouri River Breaks, Montana. Wildl. Monogr. No. 20,

79 pp.

, and C. J. Knowles. 1976. Population ecology and habitat relation-
ships of white-tailed deer on river bottom habitats of eastern Montana,
pp. 109-116. In: Montana Deer Studies. Job Compl. Rept., Montana Dept.

Fish and Game, Fed. Aid Proj. W-120-R-7. 170 pp.

Swenson, J. 1978. Intake terrestrial wildlife study-final report. Montana
Dept. Fish and Game and Intake Water Co. Unpubl. report. 72 pp.

Submitted by: Kenneth L. Hami -tn

-17 5-

JOB TITLE: Population ecology and habitat relationships of mule deer and

white-tailed deer in the prairie-agricultural habitats of
eastern Montana.

r

ABSTRACT:

Population dynamics of mule deer in the prairie-agricultural type are
discussed and compared with previous findings. Population estimates indicate
an approximate 30 percent increase in mule deer numbers since 1977-78. The
mule deer population has increased each year since 1975. Moderate overwinter
mortality occurred during 1978—79. Post-season male/100 female ratios
indicated that harvests in this type of habitat and terrain can quickly
reflect change in hunting season type and pressure.

- C

I

-176-

JOB TITLE:

Population ecology and habitat relationships of mule deer
and whxte tailed deer in the prairie-agricultural habitats
of eastern Montana.

OB OBJECTIVE: To determine the environmental requirements of mule deer

and white-tailed deer and factors regulating deer popula-
tions in the prairie-agricultural habitats in eastern Montana.

To determine the effects of various potentially competing
land use and management practices upon deer in eastern
Montana.

To develop new and Improved guidelines for management of
deer populations and their habitats in eastern Montana.

INTRODUCTION:

The Terry deer study was Initiated in September 1975 as a part of the state-
wide deer research project. The general objective was to determine factors
affecting and limiting mule deer {Odoooileus hmionus) and white-tailed
deer {OdDeo%leus v^vgln%arm)n^mhexs in the prairie-agricultural types of
eastern Montana. Field studies were conducted from September 1975 through
1978 "hi'^^’/i^ldwork was continued on a part-time basis. During

a “ “ population ostliaates

and follow population dynamics. Coincident with aerial surveys, information
was obtained on deer distribution and habitat use. Information collected
previously was reported by Hamlin (1976, 1977 and 1978)

STUDY AREA

The study area is located in north Prairie and southwestern McCone counties

of TerrraL^ r . ^^^hway 253 , starting approximately 10 miles northwest
Terry and extending north to approximately 4 miles south of Brockway. The
study area extends as far west as Little Sheep Mountain on the southern
oundary and 5 miles west of Brockway on the northern boundary (Fig. 1).
Approximately 230 square miles are included within the study area Lundarles.

A general description of the topography, vegetation,
the area was Included in Hamlin (1976).

land uses and history of

METHODS

(Pipe’' Super cub) aerial surveys were made to obtain population
estimates, s^ ^ge classifications, distribution and habitat use durlne
two periods in 1979: post-hunting season (January) and spring (March) ®

-177-

Figure 1. General location of the study area.

-178-

POPULATION TREND

The mule deer fawn/female and fawn/adult ratios during winter and spring
1979 (Table 1) were higher than during the same periods of any of the
three previous years. Because of complete snow cover, observational
conditions were considered good during the January flights. However,
due to the relative severity of the winter, the fawn/adult ratio decreased
by approximately 19 percent from January to March, but was still higher
than the ratios for any of the previous three years. Fawn/adult ratios
for white— tailed deer also indicated that while overwinter fawn mortality
occurred, it was not severe. Prior classifications of deer on the study
area can be found in Hamlin (1976, 1978).

Population estimates for mule deer and the computations involved in these
estimates are shown in Figure 2 and Table 2. Population estimates indicated
an approximate 30 percent increase in mule deer numbers over 1977-78. Hamlin
(1978) discussed some of the reasons that observed population levels will
differ somewhat from the expected levels even if every animal on the study
area was counted. Estimates of total numbers are believed to be accurate
within 5—10 percent. One of the largest discrepancies in observed vs. expected
population levels occurs during winter in the adult male category (Table 2)
because the expected population level does not account for hunting mortality
(see- hunting mortality). Additional variation has been introduced during the
last' "two years due to apparent overwinter mortality. Without marked deer,
estimates of adult winter mortality have been "educated guesses" based on
the level of fawn mortality. An estimate of 5 percent overwinter mortality
of adults lias been used for the last two winters. The level of fawn mortality
was determined from calculations based on changes in fawn/adult ratios, taking
the 5 percent adult loss into account.

As previously discussed (Hamlin 1978), population estimates of white-tailed
deer cannot be made on this area without more intensive effort.

HUNTER HARVEST

Numbers of mule deer killed on the study area were estimated by field checks
in 1975, a telephone survey of permit holders in 1976, and by pre-to-post
season changes in db*/?? ratios and observed versus expected number of males
in 1977 and 1978. Hunting unit boundaries v;ere changed prior to the 1976
hunting season, so figures are not entirely comparable. However, most of the
decline in hunting pressure and harvest, 1975-78 (Table 3), appears to have
resulted from more restrictive seasons rather than the boundary changes. The
preliminary indication from post-season dW/?? ratios is that mule deer
harvest in the type of terrain and habitat prevalent on the study area
xs easily influenced by type and intensity of hunting pressure.

Table 1. Deer classifications on the Terry study area during winter and spring 1979.

Species

Total

Animals

Total

Males

Ylg.

Males

Females

Adults

Fawns

Unci .

Fawns/
100 Adults

Fawns/

100 Females

January

South area

WTD

51

-

-

-

21

25

-

119

-

MD

396

35

18

163

198

185

14

93

113

North area

WTD

91

_

—

37

18

36

49

-

MD

121

-

-

40

40

38

43

95

95

Entire area

WTD

142

_

_

58

43

36

74

-

MD

517

}

35

—

203

238

223

57

94

110

March

Entire area

WTD

59

-

-

-

36

23

-

64

-

MD

289

-

-

-

164

125

-

76

-

-179-

NUMBER OF MULE DEER

-IRO-

Figure 2. Spring population estimates of mule deer on the Terry study
area.

-181-

Table 2. Population estimates for mule deer on the Terry study area.

Total

Adults

Fawns

Adult

Females

Adult

Males

Observed

Winter 75-76

153

105

48

93

12

+ 15% missed

180

124

56

109

15

Calculated

+

28

28

June 1976

180

180

—

137

43

X

.58 —

58 Fawns/100 Adult

‘ ■- *

79

Females observed.

fawns

winter 1976-77.

Calculated

Winter 76-77

259

180

79

137

43 ‘

Observed

Winter 76-77

252

175

77

132

43

Calculated

June 1977

260

260

—

178

82

X

.75 —

75 Fawns/ 100 Adult

_ . ,

134

Females observed.

fawns

winter 1977-78.

Calculated

Winter 77-78

394

260

134

178

82

Observed

Winter 1977-78

413

261

152

204

57

Calculated*

June 1978

348

240

108

188

52

348

348

—

242

109

X

1.10 —

110 Fawns/100 Adult

266

Females observed.

fawns

winter 1978-79.

J-

Calculated

Winter 78-79

614

348

266

242

109

Observed

Winter 78-79

517

267

250

228

39

Calculated**

June 1979

452

257

195

219

38

452

452

—

316

136

*estimated 5%

adult loss

and 27%

fawn loss

overwinter

**estimated 5%

adult loss

and 22%

fawn loss

overwinter

-182-

Table 3. Hunting seasons and harvest in the hunting units including the
study area, 1975-1978.

Type of

Hunting Season

Year

No. of^
Hunters

Est. no.^
of WTD
Killed

Est. no.^
of MD
Killed

Est. no. of
MD Killed
on Study Area

Post-season
MD dtr/lOO??
Ratio

2 deer E.S.

"B" tag WTD only

1975

3,695

814

828

60

13/100

1 deer E.S. -WTD
+

50 E.S. permits-MD

1976

1,147

517

27

0

33/100

1 deer E.S. -WTD
+

200d'cf permits-MD

1977

1,096

400

73

20

28/100

1 deer E.S. -WTD
+

1 deer dtC only-MD

1978

1,969

663

480

60

17/100

^Data from Montana

Department of

Fish, Wildlife and

Parks harvest

surveys .

LITERATURE CITED

Hamlin, K. L 1976 Population ecology and habitat relationships of mule deer

prairie-agricultural habitats of eastern Montana,
n. Montana Deer Studies. Job Progress Report, Project W-120-R-7.

PP • 1 jy—iju •

ecology and habitat relationships of mule deer and
white-tailed deer in prairie-agricultural habitats of eastern Montana,
n. Montana Deer Studies. Job Progress Report, Project W-120-R-8.

PP • •

’ P°P'^l3tion ecology and habitat relationships of mule deer and

white tailed deer in prairie-agricultural habitats of eastern Montana
on’ Studies. Job Progress Report, Project W-120-R-9.

PP . Xoj-iy/,

Submitted by: Kenneth L. Hamlin

I