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by
Peter R. Martin
Planni·n~ Ecologist
Montana Dept. of Fish and Game
Forsyth, MT
TECHNICAL REPORT NO. 6
conducted by the
Water Resources Division
Montana Department of Natural Resources and Conservation
32 So. Ewing
Helena, MT 59601
Bob Anderson, Project Administrator
Dave Lambert, Editor
for the
Old West Regional Commission
228 Hedden Empire Building
Billings, MT 59101
Kenneth A. Blackburn, Project Coordinator
July 1977
1730 K Street, N. W.
Suite 426
The Old West Regional Commission is a Federal-State
partnership designed to solve regional economic
problems and stimulate orderly economic growth in
the states of Montana, Nebraska, North Dakota,
South Dakota and Wyoming. Established in 1972
under the Public Works and Economic Development
Act of 1965, it is one of seven identical commissions
throughout the country engaged in formulating and
carrying out coordinated action plans for regional
economic development.
COMMISSION MEMBERS
State Cochairman
Gov. Thomas L. Judge of Montana
Alternate: Dean Hart
Federal Cochairman
George D. McCarthy
State Members
Gov. Edgar J. Herschler of Wyoming
Alternate: Steve F. Freudenthal
Gov. J. James Exon of Nebraska
Alternate: Jon H. Oberg
Gov. Arthur A. Link of North Dakota
Alternate: Woody Gagnon
Gov. Richard F. Kneip of South Dakota
Alternate: Theodore R. Muenster
COMMISSION OFFICES
201 Main Street
Suite D
Washington, D. C. 20006
202/967-3491
Rapid City, South Dakota 57701
605/348-6310
Suite 228
Heddon-Empire Building
Billings, Montana 59101
406/657-6665 .
i i
FOREWORD
The Old West Regional Commission wishes to express its appreciation for
this report to the Montana Department of Natural Resources and Conservation,
and more specifically to those Department staff members who participated
directly in the project and in preparation of various reports, to Dr. Kenneth A.
Blackburn of the Commission staff who coordinated the project, and to the
subcontractors who also participated. The Yellowstone Impact Study was one
of the first major projects funded by the Commission that was directed at
investigating the potential environmental impacts relating to energy develop-
ment. The Commission is pleased to have been a part of this important research.
George D. McCarthy
Federal Cochairman
FIGURES.
TABLES .
ABBREVIATIONS USED IN THIS REPORT.
PREFACE.
The River . .
The Conflict.
The Study ..
Acknowledgments
INTRODUCTION
METHODS.
EXISTING SITUATION
Habitat Requirements.
Beaver. . .
Mink. . . . . . .
Muskrat .... .
River Otter .. .
Inventory of Animals.
Beaver. . . . . .
t~i n k. . . . . . .
Muskrat .....
Beaver Cache Characteristics.
Comparison of Historical Flows with Population.
Trapping Income . . . .
IMPACTS OF WATER WITHDRAWALS . .
Projections of Future Use .
Impact of Yellowtail Dam on Bighorn River
Potential Impact of Altered Streamflows on Furbearers
SUMMARY
APPENDIXES
A. Trapping Data for Beaver, Mink, and Muskrat, 1954-74.
B. Trapping Correlations and Regressions, 1960-74.
C. Trapping Seasons and Restrictions in Department of
Fish and Game Regions 5 and 7, 1960-74.
LITERATURE C !TED . . . . . . . . . . . . . . . . . . . .
iv
v
vi
vii i
1
1
1
5
6
7
9
11
11
11
11
14
15
15
23
27
28
28
36
40
45
45
45
46
47
49
51
65
73
77
\
:.;
1. Yellowstone River Basin .... 3
2. Beaver lodge and cache next to willow stand on Yellowstone
River backwater . . . . . . . . . . . . 12
3. Beaver lodge and cache in backwater of the Yellowstone River 12
4. Beaver lodge in a high water channel of the Yellowstone River
(at Isaac Homestead) which beaver have dammed. 13
5. Beaver bank den high water entrance. . . . . . . . . . . 13
6. Beaver cache, beaver drag trail, bank den entrance, and
biologist, Pete Martin . . . . . . . . ..... . 14
7. Relative density of beaver caches on the Yellowstone,
Tongue, and Bighorn rivers in 1975 . . . . . . ..... 17
8. Beaver densities of the Yellowstone, Tongue, and Bighorn
rivers in 1974 and 1975 by study section. . . . . . . . . .... 19
9. Beaver caches/km vs. percentage of caches found in natural
offstream sites on the Yellowstone and Bighorn rivers. . . .... 33
10. Beaver caches/km vs. percentage of caches found next to
willow bank vegetation on the Bighorn and Tongue rivers ....... 34
11. Beaver caches/km vs. percentage of caches found next to
willow-cottonwood bank vegetation on the Bighorn and
Tongue rivers . . . . . . . . . . . . . . . . . . . . 35
12. Beaver cache count vs. recorded f1 ows of the Ye 11 o~1stone
River at Bi 11 i ngs in February, June, and September . . . . . . . . . 39
13. Beaver cache count vs. recorded flows of the Yellowstone
River at Miles City in February, June, and September ........ 40
v
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Furbearer species and numbers trapped in Fish and Game
·Regions 5 and 7 during the 1973-74 fur trapping season. .
Beaver cache counts on the Yellowstone River, 1974
and 1975 . .
Beaver cache counts on the Tongue River, 1974 and 1975.
Beaver cache counts on the Bighorn River, 1974 and 1975
Historical beaver cache counts on three sections of the
Yellowstone River, the Bighorn River, and the Tongue
River . . . .
Beaver, mink, and muskrat trapped state-wide and in Fish
and Game Regions 5 and 7, 1960-74 . .
Beaver, mink, and muskrat trappers state-wide and in Fish
and Game Regions 5 and 7, 1960-74 . .
Average catch per trapper for beaver, mink, and muskrat
state-wide and in Fish and Game Regions 5 and 7, 1960-74.
Average pelt price for beaver, mink, and muskrat state-
wide and in Fish and Game Regions 5 and 7, 1960-74
(dollars) ...................... .
Correlation coefficients of linear regression analysis of
numbers of furbearers trapped vs. numbers of trappers,
average catch per trapper, and average pelt price
Characteristics of observed caches on the Yellowstone
River, as percentages . . . . .
Characteristics of observed caches on the Tongue River,
as percentages . .
Characteristics of observed caches on the Bighorn River,
as percentages . . . .
.
.
.
Correlation coefficients of linear regression analysis of
beaver cache/km data with cache location, river morphology,
and bank vegetation data on the Yellowstone, Bighorn, and
Tongue rivers . . . . . . . . . . . . . . . . . . . . ...
vi
. 16
20
21
21
. 22
. 24
24
25
25
26 .
29 .
30 . .
30
32
15.
16.
17.
Correlation coefficients of linear regression analysis
of numbers of furbearers trapped in Fish and Game
Regions 5 and 7 compared with various flows of the
Yellowstone River at Billings and Miles City.
Correlation coefficients of beaver population data
(number of caches) as related to flow data on the
Bighorn, Tongue, and Yellowstone rivers determined
by linear regression analysis ........ .
Total dollars per species and average dollars
realized per species per trapper for all species
reported during the 1973-74 fur trapping season
in Fish and Game Regions 5 and 7 ....... .
• 0 • • 0 •
lB. Total dollars and average dollars realized per
trapper per species in Fish and Game Regions 5
and 7, 1960-74 ............... .
19. Residences of Yellowstone River Bas in trappers.
vii
37
38
41
43
44
af = acre-feet
af/y = acre-feet per year
cfs = cubic feet per second
em = centimeter
DFG = Montana Department of Fish and Game
km = kilometer
km3 = cubic kilometers
m = meter
mi = mi 1 e
mmaf = million acre-feet
mmt/y = mi 11 ion tons per year
tr = trace
USGS = United States Geological Survey
vi i i
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1
THE RIVER
The Yellowstone River Basin of southeastern Montana, northern Wyoming,
and western North Dakota encompasses approximately lBO,OOO km2 (71 ,000 square
miles), 92,200 (35,600) of them in Montana. Montana's portion of the basin
comprises 24 percent of the state's land; where the river crosses the
border into North Dakota, it carries about B.8 million acre-feet of ~~ater per
year, 21 percent of the state's average annual outflow. The mainstem of the
Yello~1stone rises in northwestern Wyoming and flows generally northeast to its
confluence with the Missouri River just east of the Montana-North Dakota
border; the river flows through t1ontana for about 550 of its 680 miles. The
major tributaries, the Boulder, Stilh1ater, Clarks Fork, Bighorn, Tongue, and
Powder rivers, all flow in a northerly direction as shown in figure 1. The
western part of the basin is part of the middle Rocky ~ountains physiographic
province; the eastern section is located in the northern Great Plains (Rocky
Mountain Association of Geologists 1972).
THE CONFLICT
Historically, agriculture has been f1ontana's most ir.1portant industry. In
1975, over 40 percent of the primary employment in Montana was provided by
agriculture (!1ontana Dep~rtment of Community Affairs 1976). In 1973, a good
year for agriculture, the earnings of labor and proprietors involved in
agricultural production in the fourteen counties that approximate the
Yellowstone Basin were over $141 million, as opposed to $13 million for
mining and $55 million for manufacturing. Cash receipts for Montana's
agricultural products more than doubled from 1968 to 1973. Since that year,
receipts have declined because of unfavorable market conditions: some
improvement may be in sight, however. In 1970, over 75 percent of the
Yellowstone Basin's land was in agricultural use (State Conservation Needs
Committee 1970). Irrigated agriculture is the basin's largest ~1ater use,
consuming annually about 1.5 million acre-feet (af) of water (Montana DNRC
1977).
There is another industry in the Yellowstone Basin which, though it con-
sumes little 1·1ater now, may req•Jire r.1ore in the future, and that is the coal
deve 1 opment industry. In 1971 , the North Centra 1 Power Study (North Centra 1
Power Study Coordinating Committee 1971) identified 42 potential power plant
sites in the five-state (Montana, North and South Dakota, Hyoming, and
Colorado) northern Great Plains region, 21 of them in Montana. These plants,
all to be fired by northern Great Plains coal, ~1ould generate 200,000 megawatts
(mw) of electricity, consume 3.4 r.1illion acre-feet per year (mmaf/y) of 1~ater,
and result in a large population increase. Administrative, economic, legal,
and technological considerations have kept most of these conversion facilities,
identified in the North Central Power Studv as necessary for 1980, on the
drawing board or in the courtroom. There is now no chance of their being
comp 1 eted by that date or even soon after, which ~Ji 11 de 1 ay and d imi ni sh the
economic benefits some basin residents had expected as a result of coal
development. On the other hand, contracts have been signed for the mining
of large amounts of Montana coal, and applications have. been approved not
only for new and expanded coal mines but also for Colstrip Units 3 and 4,
twin 700-mw, coal-fired, electric generating plants.
In 1975, over 22 million tons of coal were mined in the state, up from
14 million in 1974, 11 million in 1973, and 1 million in 1969. By 1980, even
if no new contracts are entered, Montana's annual coal production will exceed
40 million tons. Coal reserves, estimated at over 50 billion economically
strippable tons {t-lontana Energy Advisory Council 1976), pose no serious con-
straint to the levels of development ~rejected by this study, which range
from 186.7 to 462.8 million tons stripped in the basin annually by the year
2000. Strip mining itself involves little use of water. How important the
energy industry becomes as a ~1ater user in the basin will depend on: 1) how
much of the coal mined in Montana is exported, and by what means, and 2} by
what process and to what end product the remainder is converted within the
state. If conversion follows the patterns projected in this study, the energy
industry will use from 48,350 to 326,740 af of water annually by the year 2000.
A third consumptive use of water, municipal use, is also bound to
increase as the basin population increases in response to increased employment
opportunities in agriculture and the energy industry.
Can the Yellowstone River satisfy all of these demands for her water?
Perhaps in the mainstem. But the tributary basins, especially the Bighorn,
Tongue, and Powder, have much smaller flows, and it is in those basins that
much of the increased agricultural and industrial water demand is expected.
Some impacts could occur even in the mainstem. What would happen to
water quality after massive depletions? How would a change in water quality
affect existing and future agricultural,industrial, and municipal users?
14hat would happen to fish, furbearers, and migratory waterfowl that are
dependent on a certain level of instream flow? Would the river be as
attractive a place for recreation after dewatering?
One of the first manifestations of Montana's growing concern for water
in the Yellowstone Basin and else~1here in the state was the passage of
significant legislation. The ~Jater Use Act of 1973, which, among other
things, mandates the adjudication of all existing ~1ater rights and makes
possible the reservation of 1~ater for future beneficial use, 11as followed
by the Hater Moratorium Act of 197 4, ~1hi ch de 1 ayed action on major
applications for Yellm·Jstone Basin 11ater for three years. The moratorium,
by any standard a bold action, was prompted by a steadily increasing rush of
applications and filings for water (mostly for industrial use) which, in two
tributary basins to the Yello~1stone, exceeded supply. The DNRC's intention
during the moratorium was to study the basin's water and related land
resources, as well as existing and future need for the basin's water, so that
2
YEllowsTONE RIVER BASIN
0 10 20 40 60 80 100 Miles
Ui.HJ I I I I I
0 10 20 40 60 80 100 Kilomelers
~ I I I I
'
MUSSELSHELL
WHEATLAND I
' -------~-J VALLEY
' ~----~-
L-_i.' -~""'"'~--
GOLDEN\
/
' CARBON
YELLOWSTONE ' )
NATIONAL PARK ' (
N YELLOWSTONE
RIVER BASIN
\. GARFIELD
' ;
'\--
\
)
BIG HORN
RESERVATION ~·
~-----~-----''--
WYOMING
---,
--l,
I
I
McCONE DAWSON
PRAIRIE
------, ---. ~>-'' I
I POWDER I
ASHLAND
I BROADUS •
1
GLENDIVE)
J
J , -----.--w 1 B A UX ' I
1
,
the state would be able to proceed wisely with the allocation of that water.
The study 1~hich resulted in this series of reports 1~as one of the fruits of
that intention. Several other Yello~1stone water studies were undertaken
during the moratorium at the state and federal levels. Early in 1977, the
45th t•iontana Legislature extended the moratorium to allov1 more time to con-
sider reservations of water for future use in the basin.
THE STUDY
The Yellov1stone Impact Study, conducted by the Water Resources Division
of the Montana Department of Natural Resources and Conservation and financed
by the Old Hest Regional Commission, was designed to evaluate the potential
physical, biological, and water use impacts of 1·1ater withdrav1als and water
development on the middle and lower reaches of the Yellowstone River Basin in
Montana. The study's plan of operation was to project three possible levels
of future agricultural, industrial, and muncipal development in the
Yellowstone Basin and the streamflow depletions associated with that develop-
ment. Impacts on river morphology and water quality were then assessed,
and, finally, the impacts of altered streamflow, morphology, and water
quality on such factors as migratory birds, furbearers, recreation, and
existing water users were analyzed.
The study began in the fall of 1974. By its conclusion in December of
1976, the information generated by the study had already been used for a
number of moratorium-related projects--the EIS on reservations of water in
the Yello1·1stone Basin, for example (Montana DNRC 1976). The study resulted
in a final report summarizing all aspects of the study and in eleven
specialized technical reports:
Report No. 1
Report No. 2
Report No. 3
Report No. 4
Report No. 5
Report rio. 6
Report No. 7
Future Development Projections and Hydrologic Modeling in
the Yellowstone River Basin, Montana.
The Effect of Altered Streamflow on the Hydrology and
Geomorphology of the Yellowstone River 3asin, t·lontana.
The Effect of Altered Streamflow on the Hater Quality of
the Yellowstone River Basin, Montana.
The Adequacy of Montana's Regulatory Framework for Water
Quality Control
Aquatic Invertebrates of the Yellowstone River Basin,
t·lontana.
The Effect of Altered Streamflow on Furbearing r1ammals of
the Yellowstone River Basin, Montana.
The Effect of Altered Streamf101~ on ~ligratory Birds of the
Yellowstone River Basin, Montana.
5
Report No. 8
Report ilo. 9
Report No. 1 0
Report No. 11
The Effect of Altered Streamflow on Fish of the
Yellowstone and Tongue Rivers, Montana.
The Effect of Altered Streamflow on Existing Municipal
and Agricultural Users of the Yellowstone River Basin,
Montana.
The Effect of Altered Streamflow on Water-Based Recreation
in the Yellowstone River Basin, Montana.
The Economics of Altered Streamflm~ in the Yell0'.·1stone
River Basin, Montana.
ACKNOWLEDGMENTS
This report was reviewed by and guidance received from John C. Orth,
Director of the Montana Department of Natural Resources and Conservation;
Orrin Ferris, Administrator of the DNRC's Water Resources Division; and
Carole Massman, of the DNRC's Special Staff.
Other DNRC personnel providing assistance were Shari Meats, Jim Bond,
and Pam Tennis, who performed editing and writing tasks. Graphics were
coordinated and performed by Gary Wolf and Dan Nelson, with the assistance
of June Virag and Gordon Taylor and of D. C. Howard, who also designed and
executed the cover.
6 •
' ~
The goal of this study was to assess the impact of reduced streamflows
on furbearing mammals in the Yellowstone River Basin. Species present,
their relative abundance, and important habitat types for each were to be
determined. The flow-related impacts on each species and on the supplemental
income of fur trappers were also to be assessed. The primary furbearing
species studied was the beaver (CastoP canadensis). Other species studied,
but 11ith less emphasis, were mink (MusteZa visonJ and muskrat (Ondatm
zibethicus).
The two-year study began in the fall of 1974 and extended through the
summer of 1976. Field work was confined to the Yellowstone River from Big
Timber to the North Dakota border, the Bighorn River from Yellowtail Dam to
its mouth, and the Tongue River from the Tongue River Reservoir to its mouth.
7
I
I
'
r
During the fall season of 1974 and 1975, beaver caches were located by
aerial survey throughout the study area and plotted on maps (~'' = 1 mile).
During the 1975 survey, several parameters for each cache were recorded
during the aerial survey:
1) location
2) river morphology
3) bank vegetation
4) primary cache vegetation
Cache location was defined as:
1) onstream--a) mainland or b) island
2) offstream--a) manmade or b) natural.
River morphology was categorized as: 1) braided--more than two water
channels; 2) split--two water channels; or 3) straight--one water channel.
Bank vegetation was described as: 1) willow, 2) cottonwood, 3) mixed
willow and cottonwood, or 4) other.
Vegetation in the cache was divided into two categories: 1) willow
and 2).other.
Historical beaver population data were obtained from unpublished data
in Montana Department of Fish and Game (DFG) regional files.
Several fur harvest parameters for beaver, mink, and muskrat, including
estimated numbers trapped, total number of trappers, average catch per
trapper, and average pelt price, were summarized from DFG state-wide fur
survey and inventory reports (Egan 1975 and others).
As a part of this study, aerial photographs of the Bighorn River were
analyzed to assess the effects of flow changes due to the closure of Yellow-
tail Dam in 1965. A detailed methodology of that part of the study and the
results obtained are presented in Report No. 2 in this series (see Preface).
All statistical analyses were performed on a Monroe Programmable
Calculator, Model 17B5 Wl, following methods presented in Snedecor and
Cochran (1967).
For ease in collection and interpretation of data, each of the rivers
was divided into study sections (shown in figure 7 on page 17). Eleven
9
sections, identified in table 2 on page 20, were delineated on the
Yellowstone. Tables 3 (page 21) and 4 (page 21) show the seven and four river
sections chosen for the Tongue and Bighorn rivers, respectively.
10
HABITAT REQUIREMENTS
BEAVER
The mention of beaver habitat generally brings to mind the image of a
picturesque mountain valley with a series of beaver dams impounding water,
a centrally located lodge, and aspen and willows in abundance. While a great
number of beaver do inhabit such settings (Rutherford 1964, Hall 1960),
another niche capable of supporting healthy beaver populations is the large
prairie river system. Meriwether Clark observed beaver on the Yellowstone
River near the mouths of the Clarks Fork, Bighorn, and Tongue rivers on his
return trip in 1806 (Walcheck 1976).
The activities of men caused drastic reduction in these early beaver
populations on the plains cottom~ood river bottoms (Rutherford 1964). After
protective measures were introduced in 1876 and strengthened to a complete
ban on trapping in 1916 (Mussehl and Howell 1971), beaver populations in
Montana and elsewhere rebounded until open seasons were declared by the Fish
and Game Commission in 1953.
Beaver living along the Yellowstone River appear to utilize willow as
their primary food source. Beaver cuttings were also principally willow in
a western Montana river (Townsend 1953). Young cottonwood trees are undoubt-
edly also important (Rutherford 1964, Grasse and Putnam 1950).
A few beaver lodges and dams have been observed on side channels and
backwater areas (figures 2, 3, and 4). However, the large volume of flow
(especially during flood stages) in the main channel makes construction of
dams and lodges impossible (Gill 1972), and most beaver on the Yellowstone,
Tongue, and Bighorn rivers reside in bank dens (figure 5).
Beaver store their winter food supply in a cache (figure 6) located
near the den in the deepest available water (Grasse and Putnam 1950). By the
time ice forms, most of the cache has sunk to the river bed and is accessible
all winter.
MINK
Mink are found along streams and 1 akes where they feed on sma 11 mamma 1 s,
birds, eggs, frogs, crayfish, and fish (Burt and Grossenheider 1964).
Although mink are generally associated with water, they often wander long
distances from water in search of food (Adams 1961). Movements of mink over
11
Fiqure 2. Beaver lod~e and cache next to willow stand on Yellowstone
River backl·1ater.
' '·
Figure 3.
River.
. .;fl ~
-~ ~2<E-..: ~~-' -
~.
~ -·--
. . ·-~. -~~
.. .:c::::..___.
~,:;::-: ;;"_ :-:' ~~-~· '::'
Beaver lodge and cache in backwater of the Yellowstone
12
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1
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I " .-~
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l,! (
.c;
l' ,,
Fioure 4. Beaver lodne in a hi~h water channel of the Yellowstone
River (at Isaac Homestead) ·~~hich beaver have dammed.
Figure 5. Beaver bank den high water entrance.
13
Fioure 6. Beaver cache, beaver dra~ tail, bank den entrance,
and biolopist, Pete Martin.
30 km (20 miles) have been documented (Mitchell 1961, Hibbard and Adams 1957).
For this reason mink are much less dependent than beaver on the flows of a
river system·for survival.
MUSKRAT
r~arshes, 1 akes, and backwater areas are primary muskrat habitat
(Errington 1937, Sather 1958). Any area with emergent vegetation and stable
water levels is potential muskrat habitat.
Muskrat are versatile feeders (Errington 1941), feeding on almost any
plant growing near their dwelling. Some of the more common food plants are
cattail, river and hardstem bullrush, arrowhead, smartweed, and various
sedges and duckweeds (Sather 1958).
Sather (1958) found Nebraska muskrats inhabiting both bank dens and
"typi ca 1" houses on 1 akes and marshes. All houses were 1 ocated in water
ranging from 43.2 to 101.6 em (17 to 40 inches) in depth. His study revealed
14
1 ,
'
that muskrat populations decreased when water-level fluctuations decreased the
amount of available emergent vegetation. Friend et al. (1964) found that
muskrat experience disease, parasitic infection, and heavy weight losses in
areas with lowered water levels during winter. Ice formed on the bottoms,
freezing the muskrats' feed beds. Stable water levels result in increased
population densities through a reduction in natural mortality (Donahoe 1966).
RIVER OTTER
River otter (&utra canadensis) are apparently scarce throughout the
study area. In the 1973-74 season, only three otter were taken by trappers.
Fish comprised the majo~ portion of the diet of river otter in western
Oregon (Toweill 1974). Salmonidae were the most important single food item.
Sheldon and Toll (1964) found river otter feeding primarily on warm-water
fish in a central Massachusetts reservoir. It seems likely that river otter
prey upon more abundant fish species and those with lesser swimming ability
(Ryder 1955).
Since current fish populations in the Yellowstone would not seem to
indicate a limited food supply, some other factor, perhaps man himself,
must be responsible for the low otter populations in the study area.
li~VE~TORY OF ANIMALS
Montana's beaver trapping season begins on November 10 and ends on
March 31 of the following year. The mink and muskrat trapping seasons, both
of which also begin on November 10, end on December 31 and April 30,
respectively. There are occasionally some minor adjustments in these
opening and closing dates (see table C-1 of appendix C).
During the 1973-74 trapping season, 13 species of mammals were trapped
for their fur by 315 trappers in Fish and Game Regions 5 and 7 (table 1,
figure 7). Muskrat topped the list with an estimated 4,160 pelts taken.
Beaver were second with 2,942 pelts. Other species with over 2,000 pelts
taken included skunk (Mephitis mephitis)> raccoon (Procyon lotor), and fox
(Vulpes vulpes). Between 300 and 1,000 mink, bobcat (&ynx rufus), coyote
(Canis latrans), and badger (Tacides taxus) were trapped. Animals with
fewer than 100 pelts taken included weasel (Muotela spp.J> lynx (Lynx
canadensis), marten (Martes americana)> and river otter.
The only animals listed in table 1 and classified as "furbearers" by
state legislature are muskrat, beaver, mink, otter, and marten; all others are
either classified as ''predators'' or are unclassified (Mitchell and Greer 1971).
Because marten are closely associated with climax spruce-fir forests (Hawley
and Newby 1957), a vegetation type which does not occur along the lower
Yellowstone River, and because otter are exceptionally rare in Regions 5 and
7, only the remaining three furbearers, beaver, mink, and muskrat, were
dealt with in this study.
J5
TABLE 1. Furbearer species and numbers trapped in Fish and Game Regions 5 and
7 during the 1973-74 fur trapping season.
Species Region sa Region 7a Total
Muskrat 3,269 891 4,1GO
Beaver 1 '946 996 2 '942
Raccoon 1 '595 1 ,009 2,604
Skunk 942 1 ,267 2,209
Fox 754 1 '591 2,345
Coyote 386 437 823
Mink 346 209 555
Bobcat 273 469 742
Badger 82 251 333
Weasel 34 42 76
Canada Lynx 29 4 33
t1arten 10 0 10
Otter 2 1 3
al83 trappers in region 5, 132 in region 7
The relative density of beaver in the study area is shown in figures 7
and 8. The Yellowstone River had the most caches over the study period, with
0.87 caches/km (1.40/mile) in 1975 (table 2). The Tongue ·River supported
0.63 caches/km (1.01/~ile), and the Bighorn River had 0.55 caches/km (0.88/
mile) in 1975 (tables 3 and 4).
The Morgan Creek-to-Shadwell Creek section of the Yellowstone, mainly
downstream from Intake Diversion Dam, and the Pompey's Pillar Creek-to-Bighorn
River section had the highest densities of beaver caches, over 1.3 per river
kilometer (2/mile) for both years (table 2, figure 7). These two sections are
highly braided 1·1ith many islands and abundant willow and young cottonwood
stands. The two lowest-density sections of the Yellowstone, 8 and 11 (just
downstream from Mi 1 es City and just upstream from the North Dakota border),
are characterized by little vegetation and only one river channel.
Both the Tongue and Bighorn rivers have major water impoundments. In
1975, the river sections immediately downstream from both dams had the fewest
beaver caches for those rivers. These sections are characterized by one
channel and few deciduous trees or shrubs. In 1975, no section of the Bighorn
or Tongue rivers had 0.75 or more caches/km (tables 3 and 4), while nine of the
eleven sections of the Yellowstone attained at least that level (table 2).
The free-flowing Yellowstone River is apparently supporting a higher-density
beaver population than either the Tongue or Bighorn rivers.
Historical beaver populations as indicated by the number of caches on
the Yellowstone, Bighorn, and Tongue rivers are presented in table 5. Beaver
populations on the Columbus-to-Bighorn River reach of the Yellowstone were
high in 1956 with .977 caches/km. A population low for this reach was
16
I
~
I
l
I
-------------------------------------------
YEllowsTONE RIVER BASIN
RElATIVE DENsny of BEAVER CAchEs
IN 1975
~ Greater than 2.00 Caches per Mile
li..i..i..i.i.: (Greater than 1.24 Caches per Kilometer)
~ 1.50-1.99 (.93-1.24)
[[I§J 1.00-1.49 (.62-.93)
[II] .50-.99 (.31-.61)
Less than .50 Caches per Mile
(Less than .31 Caches per Kilometer)
Montana Department of Fish and Game Regions
0 10 20 40 60 80 100 Miles
~UitU~i£:==i1 ...... .J1:=:=:=:=~ ...... ti:=:=:==Jl
0 10 20 40 60 80 100 Kilometers
U:!HHHW=:I.. .. ..t==::l.1 .... .11==jl
I MUSSELSHELL
'
GOLDEN\
WHEATLAND I
' --------r--J VALLEY
' ~----~-
L-_i_' _..,-~r--'
'
5 l
' I
/
' _] CARBON
' .... ..i..!-..... _j
------,
YELLOWSTONE ' )
NATIONAL PARK ' (
N YELLOWSTONE
RIVER BASIN
GARFIELD
' ~
' I
INDIAN
BIG HORN
"' RESERVATION ~-
McCONE
7
POWDER
I
I
I
I
I
I
I
-~-------~--------L----L - -l-----
WYOMING
\
' {l • ~
I
I
I Llt-' ~
' I lUI ,g
' l \; ' ~
' I ,~
0 -\~ --
FIGURE 7
It
'
YEllowsTONE RIVER BASIN
RElATIVE DENsny of BEAVER CAC~Es
IN 197~
0 10 u-u-u
Greater than 2.00 Caches per Mile
(Greater than 1.24 Caches per Kilometer)
1.50 -1.99 (.93-1.24)
1.00-1.49 (.62-.93)
.50-.99 (.31-.61)
Less than .50 Caches per Mile
(Less than .31 Caches per Kilometer)
Montana Department of Fish and Game Regions
20
I
0 10 20
wu---1
' " ~
40 60 80 100 Miles
I I I I
40 60 80 100 Kilometers
I I I I
! MUSSELSHELL
WHEATLAND
GOLDEN\
'
I
' -------r--J VALLEY
' ~----~-
L __ i.·-~~~
5
~ /
' _] CARBON
YELLOWSTONE ' )
NATIONAL PARK ' (
N YELLOWSTONE
RIVER BASIN
GARFIELD
------
INDIAN
BIG HORN
RESERVATION ~
~
I
I
I
I
I
I
I ........ ----""" _______ .__
WYOMING
\
McCONE
POWDER
BROADUS •
fiGURE 7
2.0
NOTE: Each line is identified
by a number referring to one of the
river study sections. See tables
2-4 for description of sections.
1974 1975 1974 1975
Tongue Bighorn
Figure 8. Beaver densities of the Yellowstone, Tongue, and
Biqhorn rivers in 1974 and 1975 by study section .
19
"' 0
1.
2.
3.
4.
5.
6.
7.
tl.
9
10.
11.
TABLE 2. Beaver cache counts on the Yellowstone River; 1974 and 1975.
1974
Section Lengtha Caches Caches/km
Boulder River
to Stillwater River 69.0 (42.9) 46 0.67
Stillwater River
to Alkali Cr. 85.4 (53. 1 ) 53 0.62
Alkali Cr.'
to Pompey's Pillar Cr. 50.7 ( 31.5) 34 0.67
Pompey's Pillar Cr.
to Bighorn River 52.9 (32.9) 74 1.40
Bighorn River
to Froze-to-Death Cr. 41.4 (25.7) 15 0.36
Froze-to-Death Cr,
to Rosebud Cr. 73.0 (45.4} 40 0.55
Rosebud Cr.
to Tongue River 63.6 (39. 5) 29 0.46
Tongue River
to Hatchet Cr. 101.0 (62.8) 16 0.16
Hatchet Cr.
to r~organ Cr. 73.9 (45.9) 59 0.80
Morgan Cr.
to Shadwe 11 Cr. 50.0 ( 31. 1) 76 1. 52
Shadwell Cr.
to North Dakota Border 72.7 (45.2} 18 0.25
TOTALS AND AVERAGES 733.7 (456.0) 460 0.63
aLength in km (mi)
1975
Percentage of
Caches Caches/km Change
-
55 0.80 +20
64 0.75 +21
50 0.99 +47
80 1. 51 + 8
47 1. 14 +213
88 1. 21 +110
59 0.93 +103
35 0.35 +119
67 0. 91 +14
69 1.38 - 9
24 0.33 +33
638 0.87 +39
------------------~-~·
TABLE 3. Beaver cache counts on the Tongue River, 1974 and l975.
1974 1975
lengtha
Percentage
Section Caches Caches/km Caches Caches/km of Change
1. Tongue R. Dam to Deadman's Gulch 30.6 (19.0) 10 0.34 14 0.46 +40
2. Deadman's Gulch to Brown's Gulch 26.1 (16.2). 17 0.65 16 0.61 - 6
3. Brown's Gulch to Spring Cr. 55.8 (34.7) 25 0.45 41 0.73 +64
4. Spring Cr. to Hart Cr. 59.7 (37.1) 32 0.54 44 0.74 +38
5. Hart Cr. to Horse Cr. 45.7 (23.4) 22 0.48 24 0.53 + 9
6. Horse Cr. to Circle l Cr. 41.0 (25.5) 15 0.37 25 0.61 +67
7. Circle L Cr. to Mouth 45.4 (28.2) 11 0. 24 27 0.59 +145
TOTALS AND AVERAGES 304.3 (189.1) 132 0.43 191 0.63 +45
alength in km (mi)
TABLE 4. Beaver cache counts on the Bighorn River, 1974 and 1975.
1974 1975
Section Length a Caches Caches/km
Percentage
Caches Caches/km of Change
1. Yellowtail Afterbay Dam to
St. Xavier Bridge 26.5 (16.5) 6 o. 23 7 0.26 +17
2. St. Xavier Bridge to Little Bighorn R. 40.5 (25.2) 9 0.22 23 0.57 +156
3. little Bighorn R. to Pocket Cr. 39.4 (24.5) 16 0.41 28 0.71 +75
4. Pocket Cr. to l·louth 29. 1 (18.1) 16 0.55 16 0.55 0
TOTALS AND AVERAGES 135.6 (84.3) 47 0.35 74 0.55 +57
aLength in km (mi)
N
N
TABLE 5. Historical beaver cache counts on·three sections of the Yellowstone River, the Biahorn River, and the Tonque River.
Yellowstone River Reach
Columbus to Forsyth to r~iles Cit_v Biqhorn River Tongue River
Rin Horn River .,iles City to Glendive
E E E E E "'"' Q) ""' Q) ""' Q) ""' Q) ""' Q) ...... .<= ...... .<= ...... .<= ...... .<= ...... .<= 4-V> "' u 4-U> "' u 4-U> "' u 4-U> "' u 4-U> "' u 00> Q) "' 00> Q) "' 0 Q) Q) "' 0 Q) Q) "' 00> Q) "' .<= .<= u .<= .<= u .<= .<= u .<= .<= u .<= .<= u
•U u ...... •U u ...... •U u ...... •U u ...... •U u ......
0<0 "' E C<a "' E 0"' "' E 0<0 "' E 0<0 "' E zu u """ zu u ""' zu u "" zu u "" z u u ""
1953 ---80 .777 1.29 77 .~79 2.09 -- -68 .~18 2.39
1954 ---64 .622 1 . 61 83 .516 1. 94 ---llO .677 1. 48
1955 - --58 .56~ 1.77 38 .236 4.23 55 . 45 ?..2 ---
195fi 198 .977 1.02 58 .51i4 1. 77 31 .191 5. 19 ---44 .271 3.69
1957 ---46 .d47 2.24 29 . 1 All 5.55 -- -
78 .48 2.08
1962 ---49 .476 2. 1 24 . 149 6.70 ---47 .289 3.46
1965 ---7 .068 14.7 21 . 131 7.66 ---13 .08 12.5
1968 Sf! .434 2.30 34 .330 3.03 28 .174 5.74 18 . 15 6.0 30 . 185 • 5.42
1969 124 .612 1.63 32 .311 3.22 30 . 18fi 5.36 30 .25 4.1 66 .406 2.46
1974 179 .R69 1. 15 43 .505 1. 9R 60 .405 2.47 47 .347 2.R9 77 .441 2.27
1975 219 1.06 .941 84 .986 1. 01 78 .526 1.9 74 .546 1.83 137 .784 1.28
NOTE: Hyphens indicate a lack of data. All data prior tn 1974 obtained from files of riontana Department of Fish and
Game Reaional Heat'ouarters in Billinos and Miles CHy.
Distances used in calculations differed. The ones used by the Department of Fish and Game for all calculations from
1953 to 1969 were, for the three sections of the Yello~1stone in orrler of their appearance in the table, 202.7, 102.9,
and 160.9 km, and for the Tongue River, 162.5 km. The Bighorn River length used in those calculations is not knmm. The
distances used for the present study (1974 and 1975 data}, obtained from USGS Yellowstone River mileage tables, "ere, for the
five areas, 206.0, 85.2, 148.2, 135.6, and 174.7 km respectively.
----------~-~-~---
recorded in 1968 when only .434 caches/km were observed. In 1975, the number
of caches observed during this study (219) was the highest ever recorded.
Density in 1975 was 1.06 caches/km.
Observations on the Forsyth-to-Miles City reach of the Yellowstone
peaked in 1953 and 1975 with 80 and 84 caches observed, respectively. The
observance of only 7 caches in 1965 seems unreasonably low; however, the
cache survey was performed at the proper time. Either the population was that
low, the beaver delayed building caches for some reason that year, or the
observer introduced bias. The 1968 and 1969 seasons were also low with
0.33 and 0.31 caches/km observed, respectively.
Peak numbers of caches observed in the Miles City-to-Glendive reach
occurred in 1954 {83 caches) and 1975 (78 caches). Lows were observed in
1962 and 1965 when only 0.149 and 0.131 caches/km were observed, respectively.
This section of the river supported the lowest-density beaver population
on the Yellowstone River every year except 1965.
The numbers of caches/km on the Bighorn River were comparable to the
poorest section of the Yellowstone. The recorded low was in 1968, 18 caches,
while the high was 74 caches observed in 1975.
Peaks in the Tongue River beaver population were observed in 1954 and
1975 with 110 and 137 caches, respectively. The low figure was recorded in
1965 when only 13 caches were observed. The population level fluctuated'
more widely on the Tongue River than the other rivers, excluding the 1965
Forsyth-to-Miles City reach of the Yellowstone.
Looking at all five river reaches, it appears that beaver population
highs occurred in 1953, 1954, and again in 1975, with 1g75 being the highest
on record. The low apparently occurred in 1965. The Yellowstone River
sections have supported more beaver (i.e., caches/km) than either the Tongue
or Bighorn rivers. The Tongue River supported a denser population than did
the Bighorn.
Fur harvest data for beaver, mink, and muskrat for Fish and Game Regions
5 and 7 (see figure 7) and the entire state for the fourteen-year period
from 1960-61 through 1973-74 are given in tables 6, 7, 8, and 9. The same
data (numbers trapped, total number of trappers, average catch per trapper,
and average pelt price) are graphically shown in appendix A. Statistical
relationships among numbers trapped and the other parameters were determined
by linear regression analysis at the p = .05 and p =.01 levels (Snedecor and
Cochran 1967). The resulting correlation coefficients are presented in
table 10. These ·relationships which were statistically significant are
shown graphically in appendix B.
BEAVER
Numbers of beaver trapped in the study area were highest in 1960-61,
1962-63, and 1972-73. The fewest trapped occurred in the mid-60's with
1965-66 registering the low for Region 5. Over the 14 years, Region 5
averaged 1,388 beaver trapped compared to 1,022 per year in Region 7.
23
TABLE 6. Beaver, mink, and muskrat trapped state-wide and in Fish and Game
Regions 5 and 7, 1960-74.
Beaver Mink Muskrat
Season R-5 R-7 State R-5 R-7 State R-5 R-7 State
1960-61 2,300 1 ,BOO 23,000 1,048 206 8,700 2,925 428 31 • 1 00
1961-62 2,100 1 • 300 16,000 839 170 6,400 4,860 672 31 ,112
1962-63 2,100 2,100 22,000 1 ,150 512 9,100 6,642 1 ,279 45,900
1963-64 915 599 16,000 1,220 368 9,600 3,366 1 ,370 49,000
1964-65 714 294 7,800 797 154 5,800 2,722 219 22,000
1965-66 533 1 • 306 11 ,000 974 177 7,000 2,495 516 39,800
1966-67 839 533 12,200 777 11 5 6,200 2,047 130 33,100
1967-68 989 713 11 ,890 493 149 4,580 1 ,245 422 19,610
1968-69 1 ,059 818 12,405 390 192 5. 750 1 ,689 1 ,330 31 ,245
1969-70 1 ,619 922 14 ,135 641 168 8,070 2,117 1 ,256 44,270
1970-71 943 391 8,435 255 95 3,621 1 ,296 501 22,453
1971-72 1 ,005 641 10,030 213 60 3,158 1 ,439 329 24,498
1972-73 1 ,866 1 ,888 15,612 249 233 4,041 2,704 1 ,657 34,075
1973-74 1. 946 996 13.162 346 209 4,029 3,269 891 22,908
AVERAGE 1 ,388 1 ,022 13,834 671 201 6.146 2,773 786 32,219
NOTE: Variations in the lengths of trapping seasons for these years and
restrictions placed on trappers that could have affected the numbers of
furbearers trapped are explained in appendix C.
TABLE 7. Beaver, mink,and muskrat trappers state-wide and in Fish and Game
Regions 5 and 7, 1960-74.
Beaver Mink Muskrat
Season R-5 R-7 State R-5 R-7 State R-5 R-7 State
1960-61 95 51 794 92 35 831 93 29 746
1961-62 91 66 707 94 34 765 108 28 689
1962-63 74 50 635 93 35 681 95 46 650
1963-64 65 47 695 100 38 857 92 44 848
1964-65 47 24 501 92 24 611 81 18 575
1965-66 38 40 536 99 26 625 73 20 625
1966-67 57 38 586 81 21 636 76 16 651
1967-68 66 36 670 73 24 594 68 29 623
1968-69 62 46 652 53 21 558 67 29 622
1969-70 87 56 850 81 27 770 98 41 897
1970-71 50 32 556 43 17 485 57 21 578
1971-72 68 35 622 50 18 451 65 24 597
1972-73 115 83 861 69 35 606 109 56 785
1973-74 131 87 997 75 51 738 131 54 890
AVERAGE 75 49 690 78 29 658 87 33 698
24
1
I
~
I
. I
TABLE 3. Average catch per trapper for beaver, mink, and muskrat state-wide
and in Fish and Game Regions 5 and 7, 1960-74.
Beaver Mink Muskrat
Season R-5 R-7 State R-5 R-7 State R-5 R-7 State
1960-61 34.3 33. 1 30.0 11.4 5.9 10.5 31.4 14.8 41.7
1961-62 12.9 19.2 22.5 3.9 5.0 8.4 45.0 24.0 45.1
1962-63 28.5 43.0 34.6 12.4 14.9 13.4 69.9 27.8 70.6
1963-64 14.2 12.8 23.2 12.3 9.8 11.2 36.8 31.1 57.7
1964-65 14.9 12. 1 15.6 8.5 6.4 9.5 33.2 12.3 39. 1
1965-66 14.0 32.7 20.4 9.8 6.8 11.2 34.2 25.8 63.6
1966-67 14.7 14.0 20.9 9.6 5.5 9.7 26.9 8.1 50.8
1967-68 14.9 19.6 17.8 6.8 6.3 7.7 18.3 14.8 31.5
1968-69 17.2 18.4 19.0 7.4 9.2 10.3 25.1 45.6 50.3
1969-70 18.7 16.6 16.6 7.9 6.2 10.5 21.7 31.0 49.3
1970-71 18.9 12.2 15.0 6.0 5.5 7.5 22.7 23.5 38.9
1971-72 14.9 18.5 16. 1 4.2 3.3 7.0 22.2 14.0 41.0
1972-73 16.2 22.6 18. 1 3.6 6.7 6.7 24.7 29.5 43.4
1973-74 14.9 11.4 13.2 4.6 4.1 5.5 25. 1 16.5 25.8
AVERAGE 18.5 20.4 20.2 8.1 6.8 9.2 31.2 22.8 46.3
NOTE: Variations in the lengths of trapping seasons for these years and
restrictions placed on trappers that could have affected the average catch per
trapper are explained in appendix C.
TABLE 9. Average pelt price for beaver, mink, and muskrat state-wide and in
Fish and Game Regions 5 and 7, 1960-74 (dollars).
Beaver Mink Muskrat
Season R-5 R-7 State R-5 R-7 State R-5 R-7 State
1960-61 8.33 7. 91 8.86 10.89 8.06 11. 13 0.46 0.45 0.48
1961-62 7.89 7. 31 8.21 8.78 13.18 9.34 0.76 0.83 0. 77
1962-63 10.22 8.23 10.26 10.01 16.95 1 o. 71 l. 01 0.76 0.81
1963-64 8.52 9.23 10.18 13.57 15.82 12.38 0.89 0.80 0.98
1964-65 8.55 7.36 9.63 8. 79 14.41 10.18 0.86 0.67 0.88
1965-66 9.48 10.29 11.54 9.92 15. 18 10.23 1.07 1.24 1.16
1966-67 10.61 9.82 10.23 7.60 11.75 10. 01 0.69 0.66 0.72
1967-68 11 . 63 10.55 10.67 6.66 9.36 9.12 0.40 0.54 0.68
1968-69 12.59 10.81 13. 52 10.78 10.01 10.88 0.67 0.74 0.79
1969-70 10.60 9.55 11.00 5.68 9.88 8.33 0.90 0.88 0.95
1970-71 9.52 7.95 9.29 4.13 6.45 4.69 0.74 0.67 0.88
1971-72 12.47 12.78 12.69 5.02 9.79 6.03 1.07 1.06 l. 31
1972-73 15.06 12.92 15.95 9.41 15.30 11.74 l. 52 1.46 1.43
1973-74 14.47 14.62 15.95 10.29 16.74 14.46 2.00 l. 56 1.98
AVERAGE 10. 71 9.95 11 . 28 8.68 12.35 9.95 0.93 0.88 0.99
25
TABLE 10. Correlation coefficients of linear regression analysis of numbers
of furbearers trapped vs. numbers of trappers, average catch per trapper, and
average pelt price.
Region Number of Average Catch Average Pelt
Trappers Per Tra~per Price
(13 )a ( 13) ( 13) a
Beaver 5 0. 773b o.8o5b 0. 045d
7 0.562C o.s29b o.o29d
Mink 5 0.836b 0.963~ 0.594C
7 0.551C 0.893 0.623c
~1uskrat 5 0. 572~ 0.937b 0.212d
7 0.818 0.812b 0.379d
aDegrees of freedom = number of years of compatible data minus one.
bstatistical significance (p = . 01 ) of correlation (Snedecor and Cochran 1967).
cstatistical significance (p = .05) of correlation (Snedecor and Cochran 1967).
dThese correlations were not significant.
The largest number of beaver trappers was recorded in lg73-74 for both
regions, after lower peaks in 1960-61, 1961-62, 1969-70, and 1972-73. Region 5
has consistently had more beaver trappers, averaging 75, while Region 7 has
averaged 49 beaver trappers.
The average annual catch per trapper in Region 5 has decreased from highs in
the early sixties to an average of about 14.5 beaver per trapper. A slight
rise was recorded in the 1969-70 and 1970-71 seasons. Region 7 success has
fluctuated widely from 43.0 per trapper in 1962-63 to 12.1 in 1964-65 and
12.2 in 1970-71. Overall, Region 7 has averaged 20.4 beaver per trapper
compared with 18.5 beaver per trapper in Region 5.
Beaver pelt prices have averaged higher in Region 5 ($10.71) than in
Region 7 ($9.95). Both regions are below the state-wide average of $11.28 per
pelt. Prices have trended generally upward with state-wide peaks in 1968-69,
1972-73, and 1973-74. Region 5 registered its highest prices during the 1972-73
season, and the highest prices in Region 7 came in 1973-74.
Statistical analysis reveals a positive significant (p = .01) relationship
between numbers of beaver trapped and average catch per trapper in both Regions
5 and 7 (table 10, figure B-2 of appendix B). The relationship between numbers
trapped and number of trappers, although significant (p = .01 in Region 5 and
p = .05 in Region 7) had smaller correlation coefficients than calculated for
average-catch-per-trapper comparisons. There was an insignificant relation-
ship between numbers trapped and average pelt price, suggesting that the pelt
price has no effect on the number of beaver trapped. Trappers taking beaver
are probably doing it for recreation as well as profit.
26
' ~
'
Assuming that trappers, both recreationists and professionals, have a
higher catch rate when populations are higher, it seems likely that average-
catch-per-trapper curves would correlate well with population curves. Only
further study aimed at obtaining a substantial number of consecutive years
of population estimations could bear this theory out.
MINK
The 1962-63 and 1963-64 seasons were the peak mink harvest years in both
Regions 5 and 7 (table 6). The trend has been generally downward since then;
the fewest mink were caught in the 1971-72 season. There has been a slight
recovery in the last two years. Considerably more mink have been harvested
in Region 5 tnan in Region 7, with averages of 671 and 201, respectively.
Region 5 also had more mink trappers over the years (average 78) than
did Region 7 (average 29). Numbers of trappers remained relatively steady
from the 1960-61 through 1965-66 trapping seasons in Region 5, declining to
lows during the 1970-71 and 1971-72 seasons. Region 7 was stable from
1960-61 through 1963-64 at a median level. It declined in 1964-65 and was
then stable at a low level through 1971-72. Both regions showed substantial
increases in the next two years.
Average-catch-per-trapper figures indicate that Region 7 had the highest
and lowest yearly average catches, ranging from 14.9 in 1962-63 to 3.3 in
1971-72. Region 5 had a higher overall average catch (8.1 mink per trapper)
than did Region 7 (6.8). Both regions have trended downward since the highs
recorded in the early sixties.
Mink pelt prices have been consistently high in Region 7, averaging
$12.35 per pelt. Pelt prices were highest in 1962-63 and lowest in 1970-71.
Region 5 prices followed the same pattern as in Region 7 but averaged only
$8.68.
Statistical analysis revealed high correlations between numbers taken and
average catch per trapper. In Region 5, the correlation coefficient (r) was
0:963. Both Region 5 and 7 regressions were significant at the p = .01 level.
The linear regression between number of mink trapped and mink trappers was
significant in both Region 5 (p = .01) and Region 7 (p = .05). Mink pelt
prices were significantly related to the number of mink trapped in both
regions (p = .05). These data suggest that Region 5 has more mink than
Region 7. Region 5 had more mink trapped, more trappers, and a higher
average catch per trapper, even though Region 7 had a higher average pelt
price. Perhaps professional trappers enter the mink market only when prices
are right.
MUSKRAT
Region 5 far exceeded Region 7 in numbers of muskrat trapped, with an
average of 2773 per year compared with only 786 per year in Region 7. However,
the number trapped in Region 5 has decreased drastically from over 6600 in
1962-63 to lows of 1245 in 1967-68 and 1296 in 1970-71. Region 7 peaks
occurred in 1963-64 and 1972-73 at 1370 and 1657 muskrat taken, respectively.
27
Region 5 muskrat trappers numbered over 100 in 1961-62, 1972-73, and
1973-74. The highest number, 131, trapped in 1973-74. The fourteen-year
average was 87. Region 7 averaged 33 muskrat trappers per year. Peak years
were 1962-63, 1972-73, and 1973-74. The last two years have shown the
highest number of trappers on record in Region 7.
Average muskrat catch per trapper in Region 5 was 31.2 muskrats. Before
the 1966-67 season, the average catch was more than 30 muskrats per trapper,
with a peak of nearly 70 in 1962-63 (nearly 80 in 1955-56). Since the
1966-67 season, the average has been in the 20's except for 1967-63, which
had the low catch of 18.3 muskrats per trapper. Peak muskrat seasons in
Region 7 occurred in 1963-64, 1968-69, and 1969-70 with 31.1, 45.6, and 31.0
muskrats per trapper, respectively. The low occurred in 1966-67, when trappers
caught an average of only 8.1 muskrats each.
Muskrat pelt prices have increased considerably since the 1967-68 season.
That year, in Region 5, muskrat pelts brought $0.40 each; they were worth
$0.54 in Region 7. Prices in 1973-74, the highest on record, were $2.00
in Region 5 and $1.56 in Region 7. Region 5 had the highest overall average,
$0.93, while Region 7 averaged $0.88 per muskrat pelt.
Average muskrat catch per trapper, like beaver and mink catches per
trapper, had higher correlation than either number of trappers or pelt price
with numbers trapped in both regions 5 and 7. Correlation coefficients, both
significant at the p = .01 level, for the two areas were 0.937 and 0.812, respec-
tively. In Region 7, the muskrat/trapper correlation was significant at ~ = .01
while that of Region 5 was significant at p = .05. Average pelt price was '
not significantly related to the number of muskrats trapped. From these data
it seems that Region 5 has the most muskrat, the most trapped, the most
trappers, and the highest catch per trapper. That numbers trapped were not
significantly related to pelt prices in either region suggests that the
trappers trapped for recreation as well as profit.
BEAVER CACHE CHARACTERISTICS
The beaver cache parameters observed in 1975 along the Yellowstone River
are shown in table 11. Ninety-five percent of the caches were included in
this analysis; five percent were omitted due to technical failure in data
collection. Of the analyzed caches, 53 percent were constructed adjacent to
islands. Thirty-five percent were built next to mainland banks. The other
12 percent were not actually on the river but were associated with it; three
percent were in man-made structures (irrigation ditches) and nine percent
in springs or small tributaries within the Yellowstone River floodplain.
Ninety-six percent of the observed caches were included in the Tongue
River analysis (table 12); four percent were omitted because of technical
difficulties. On the Tongue River, only 7 percent of the caches were located
next to island banks. Eighty-seven percent were built next to the mainland,
and another 6 percent were found in offstream locations.
28
l
' ~
l
"' "'
-------~--· --
TABLE 11. Characteristics of observed caches on the Yellowstone River, as percentages.
Location River Morphology Cache Vegetation
Onstream Offstream
E
"'0 "'0 Q) +-' "' Q) <:: "'0 ~ "'0 .s:; Q)
"' > "'0 "' "' "' Q) 0> ... 3:
Q)l-<:: ~ E !-"'0 +-' ·~ +-' 0 !-
.s:;Q) "' <:: I ::> ·~ ·~ "' "' ~ Q)
u.n ~ ·~ <:: +-' "' ~ !-'+-~ ..c:
"'"" "' "' "' "' ... c. +-' '+-·~ +'
Section a uo -,;:: :;: z co V"l V"l 0 3: 0
1 100 45 24 7 24 22 36 11 31 100 0
2 100 48 41 0 11 34 38 17 11 100 0
3 100 58 32 0 10 36 so 4 10 100 0
4 99 61 34 1 4 65 24 6 5 100 0
5 100 60 38 0 2 62 28 9 2 100 0
6 99 52 39 7 2 60 24 7 9 100 0
7 97 53 37 7 4 26 36 28 11 98 2
8 91 22 50 0 28 9 22 41 28 100 0
9 72 54 40 0 6 48 27 19 6 98 2
10 91 57 30 5 8 62 21 5 13 100 0
11 96 61 22 9 9 74 4 4 18 100 0
AVERAGE 95 53 35 3 9 46 29 13 12 100 trb
aoescriptions of sections in table 2.
btr = trace; a value less than .OS percent
Bank Vegetation
"'0 "'0 "'0
0 <:: 0
0 "' 0 3: 3:
3: <:: 3: <::
0 0 00 !-
~ +-' ~ +-' Q)
~ +-' ~ +-' ..c:
·~ 0 ·~ 0 +-'
3: u ;,::u 0
51 0 49 0
41 6 52 2
32 2 56 10
39 0 59 1
36 0 53 11
36 1 52 11
37 4 53 7
88 0 6 6
71 2 25 2
25 2 70 3
30 4 65 0
42 2 51 5
w
0
TABLE 12. Characteristics of observed caches on the Tongue River, as percentages.
Location River Morphology Cache Vegetation
On stream Off stream
E
"0 "0 "' ... "' "' c: "0 ~ "0 .:; "' "'> "0 "' "' "' "' "' ... " "' ... c: E ... "0 ... ·-... 0 ... .,., "' c: ' " ·-·-"' "' ~ "' u"' ·-c: ... "' c. ... .... ~ .:;
.. .o ';;; "' "' "' ... ... .... ...
Sectiona uo -"" "" :z: "' V'l V'l 0 ::;:: 0
1 93 15 77 0 8 0 15 77 8 100 0
2 100 6 94 0 0 0 13 88 0 100 0
3 95 8 85 3 5 0 15 77 8 100 0
4 95 2 95 0 2 2 12 83 2 98 2
5 92 9 86 0 5 0 14 82 5 100 0
6 96 13 79 0 8 0 25 67 8 100 0
7 100 4 89 0 7 0 11 81 7 96 4
AVERAGE 96 7 87 1 5 1 15 79 6 99 1
aoescriptions of sections in table 3.
TABLE 13. Characteristics of observed caches on the Bighorn River, as percentages.
Location River Morphology Caches Vegetation
On stream Off stream
E
"0 "' ... "' -o
"' c: "0 ~ "0 .:; "' "'> "0 "' "' "' "' "' ... " E ... "0 ... ·-... 0 ... "' ... c: "' .,., "' c: ' " ·-·-"' "' ~ ... .... ' ~ .:;
u"' ·-c: ... "' c. ... .. .o "' "' "' "' ... ... .... ·-Sectiona uo -::;: "" z "' V'l V'l 0 3 0
1 100 43 29 0 29 29 14 29 29 100 0
2 96 68 18 0 14 32 9 36 14 95 5
3 100 43 50 0 7 46 29 18 7 100 0
4 100 50 44 0 6 50 25 19 6 94 6
AVERAGE 99 52 37 0 11 41 33 15 11 97 3
aoescriptions of sec~ions in table 4.
Bank Vegetation
"0 "0 "0
0 c: 0
0 .. o
" " " c: " c: 0 0 00 ...
~ ... ~ ... "' ~ ... ~ ... .:; ·-0 ·-0 ...
~ u ::.:u 0
62 15 15 8
44 0 44 13
28 3 51 18
17 7 67 10
36 0 55 9
33 4 50 13
37 4 30 30
32 4 49 15
Bank Vegetation
"0 "0 "0
0 c:o
0 .. o
" " " c: " c: 0 0 00 ...
~ ... ~ ... "' ~ ... ~ ... .:; ·-0 ·-0 ...
3 u 3U 0
71 0 14 14
55 9 36 0
36 0 46 18
50 6 44 0
48 4 40 8
/
I
On the Bighorn River (table 13), with 99 percent included in the analysis,
11 percent of the caches were offstream and 89 percent onstream, 52 percent of
them next to islands and 37 percent next to mainland banks.
Braided and split reaches of the river provided more beaver habitat than
did straight reaches, demonstrated by the fact that 46 percent of caches on the
Yellowstone were in braided sections and 29 percent were in split sections.
The Bighorn caches were located primarily in braided (41 percent) and split
(33 percent) river sections also. Only on the Tongue River, which has few
split and braided sections, were there more caches located in straight river
sections. Sixteen percent of the caches on the Tongue were located in braided
or split channel sections.
Willow (Salix spp.) is the primary food source of beaver throughout the
study area. On the Yellowstone River, willow was the primary vegetation in
100 percent of the caches. It was the primary vegetation in 99 percent and
97 percent of the caches on the Tongue and Bighorn rivers, respectively. The
bank vegetation next to 42 percent of the caches on the Yellowstone was pure
willow. Fifty-one percent of the caches were constructed next to mixed
willow and cottonwood trees (PopaZus spp). Thus, 93 percent were built
adjacent to willow or willow-cottonwood stands. On the Bighorn River, 88
percent of the caches were found next to willow or willow-cottonwood vegetation.
Eighty-one percent of the caches on the Tongue River were located next to
willow or willow-cottonwood vegetation.
Beaver population data (caches/km) were compared to cache location data
(table 14). Few significant relationships were discovered. There were negative
relationships between natural offstream sites and beaver caches/km on all
three rivers. They were significant (p = .05) on the Yellowstone and Bighorn
rivers (figure 9). The data appear to indicate that use of offstream sites
is not dependent on population levels.
On each of the three rivers, the braided sections provided the highest
positive relationships between caches/km and river morphology, though not at
significant {p = .05) levels. Field observation in the study area supports
the conclusion that beaver prefer braided sections of the river. One would
expect that, as the population of beaver increased, they would move out from
the preferred braided areas to split and even straight channel locations, thus
decreasing the percentage of caches located in the braided sections. As
indicated earlier, beaver populations are at high levels throughout the study
area. Low population levels probably would show significant numbers of caches
in the braided sections.
All three rivers demonstrated negative relationships between caches/km
and pure willow stands and positive relationships between caches/km and mixed
willow-cottonwood stands. The relationships were at significant levels
(p = .05 or higher) on the Tongue and Bighorn rivers (figures 10 and 11).
Even though willows are the primary food of beaver, some factor seems to
prevent them from locating next to pure willow stands. Since cottonwood-
willow stands occur later in the succession of island formation, after the
soil depth has increased, it may be that beaver are selecting the cottonwood-
willow sites because the bank is higher, affording a better place in which to
build their bank lodges.
31
w
"'
Table 14. Correlation coefficients of linear regression analysis of beaver cache/km data with cache
location, river morpholo9y, and bank vegetation data on the Yellowstone, Bighorn, and Tonque
rivers.
Location River Morpholoqy Bank Vegetation
"0 "0 "0
E 0 c::: 0
"0 "' .., 0 "'0 c::: ~"' "0 ""' 3: 3:
"0 "' ., ... <lJ 0" 3: c::: 3:C:::
Degrees c::: ~ ... .., "0 .., ·~ 0 0 00
"' c::: "'"' ·~ ·~ "' ~ .., ~..,
of ~ ·~ .., .... "' ~ ... ~ .., ~..,
"' "' ., .... ... a. .., ·~ 0 ·~ 0 River Freedoma -::E zo "' Vl Vl :3: u :>:u
Yellowstone ( 10) 0.502 0.091 -0.632b 1).421 0. 196 -0.509 -0.485 -0.363 0.454
Bighorn (3) 0.198 0.472 -0.908b 0.670 0.550 -0.417 -0.967c 0.?23 0.947b
Tongue (6) -0.661 0.574 -ll.483 0.557 -0.097 0.089 -0.864c -0.348 0.717b
asections of river minus one.
bstatistical
/
significance (p = . 05) of correlation. Snedecor and Cochran (1967) . .
' .
cstatistical significance (p = . 01) of correlation. Snedecor and Cochran ( 1967) .
' '
f
I
2.0
1.5
~ ., -.,
E
0
:><: .. .,
a. ., 1.0 .,
.c;
u
0 u
~ .,
>
0 .,
([I
.5
0
0
•
\
~ .
\
\
\ . \ . \
'
I
I • ·.+
·.
-¢-
•
I
I
\
I .I
I
I
I ·.* •• I .,
• I"
I ••
I
I
I
I
I
I
I
I
I
I
10 20
Percentage
•
------• Yellowstone Rive.r
· ·· ·· ... ····-¢-Bighorn River
•
.. -¢-
30 40 50 60 70 eo 90 100
of Caches Found in Natural Offstreom Sites
Fioure 9. Beaver caches/km vs. ~ercentage of caches
found in natural offs t ream sites on the Yellows tone and
Biqhorn rivers.
33
2.0
1.5
~ .. -.,
E
0
::.::
~ .,
Q. .. 1.0 .,
.c
u
0 u
~ .,
>
0 .,
ID
.5
0
0 10
- - - -• Tongue River
· · · ···· ·· · -9-Bighorn River
. .. ... . -9-. ';+ · ...
.. ... .. . . :¢--¢-
20 30
. ---+
...: .......
' .• . -
40 50 60
:q..
70 BO 90
Percentage af Caches Found Next to Willow Bank Vegetation
100
Fiqure 10. Beaver caches/km vs. oercentaoe of caches
found next to willow bank ve~etation on the Bighorn and
Ton<1Ue rivers.
34
' j
~
CD -CD
E
0
:.::
~
CD
Q. .. .,
.1:. u
0 u
~
CD >
0
1:
..
ID
f ~ ,.
2.0
1.5
1.0
. 5
, ..
•
,' ....
, ~·
.. , ,
-------------A •• • ,' Y. , • -_:{..--. . ..,.-.
-~-·-~ -• -..
----· • Tongue River
· · · · ·· · ·· · ~ Bighorn River
0 4---~--~--~--~--~--~--~--~--~--~
10 20 30 40 50 60 70 80 90 100
Percentage of Caches found Next to Willow-Cottonwood Bonk Vegetation
Fiqure 11. Beaver cache/km vs. percentaqe of caches
found next to wi llo~1-cottonwood bank ve(Jetation on the
Bighorn and Tonque rivers.
35
COMPARISON OF HISTORICAL FLOHS WITH POPULATION
The numbers of beaver, mink, and muskrat trapped in Fish and Game Regions
5 and 7 were compared to flows of the Yello~1stone River at Billings and Miles
City (table 15). Beaver trapped in Region 5 demonstrated the only significant
relationships to flow. In each case, except with flows in January, the number
trapped was inversely related to the flow; that is, as flows increased, catch
decreased. High flows probably affect not only beaver (as described below)
but also trappers; access to the river and boat maneuverability may be reduced.
The greatest relationship occurred in the comparison of numbers trapped to
calendar year flow; even there, however, only 39 percent of the variation
could be attributed to flow. Mink relationships were generally negative and
not significant. Muskrat relationships, none significant, were negative in
Region 5 but positive in Region 7. However, mink are not dependent on the
river for survival, and most muskrat were probably not trapped on the river.
The relationship between beaver populations (as expressed by the number
of beaver caches) and flows at various times of the year is shown in table 16.
The number of caches on the Yellowstone from Columbus to the mouth of the
Bighorn River was significantly (p = .01) and negatively related to the flow at
Billings in February, the winter low-flow month. With an r value of 0.993
(r2 = 0.99), almost all of the variation can be attributed to changes in flow.
The number of degrees of freedom (four in this case) is small, but it seems
likely that, in this stretch of river, high winter flows are detrimental to
beaver populations. Wilsson (lg68) reported that winter fluctuations of water
levels in the Faxalven River in Sweden were responsible for the loss of many
caches and lodges, seriously affecting the beaver population. Flows in the
Yellowstone in September, the summer low-flow period, were also negatively
related to cache number but not in a significant manner. The high flows in
June were positively related (figure 12) to beaver cache numbers, but the
degree of relation was small (r2 = 0.08).
The relationship of flow at Miles City to the number of caches between
Forsyth and Miles City over an eleven-year period was negative in all instances.
The only significant relation (figure 13) occurred during September. Only
35 percent of the relationship could be attributed to the river flow level.
The relationships of flow at Sidney and beaver caches from Miles City to
Glendive were all negative and insignificant.
The relationships on the Tongue River were all positive and insignificant.
January and June flows on the Bighorn River were negatively related to beaver
cache numbers; August and previous water year flows were positively related.
None of the Bighorn relationships were at significant (p = .05) levels.
It seems apparent that the present flows in the Yellowstone River Basin
are not importantly related to the number of beaver. The greatest potential for
influence appears to be related to high flows during the winter months. Such
flows could dislodge caches, washing away the beavers' food supply, or flood
beaver lodges, causing the beaver to die of exposure. Low flows in winter
could leave caches and lodges exposed to the elements, making them inaccessible
to the beaver and/or making the beaver accessible to predators, including man.
36
II
w .....
Table 15. Correlation coefficients of
Fish and Game Regions 5 and
and Miles City.
linear regression analysis of numbers of furbearers trapped in
7 compared with various flows of the Yellowstone(River at Billings
Region
5
7
5
7
5
7
Prior to Traj>ping Season
Water Yeara
( 10) f
-0.605
-0.210
-0.389
+0.089
-0. 150
+0.353
Octoberb
( 15) f
-0.509g
-0. 172
-0.188
-0.310
-0.328
+0.203
I
During Trapping Season
Calendar YearC Water Y~ard
( 15) f ( 15)
BEAVER
-0.623h -0.488g
-0.244 -0.471
MINK
-0.232 -0.314
-0. 167 -0. 154
MUSKRAT
-0.282 -0.068
+0.252 -0.039
NOTE: All coefficients not identified by footnotes g or h were not significant.
Januar{
( 15)
+0.280
-0.368
-0.038
-0.330
-0. 158
+0. 193
aThe total flow for the year beginning October l and ending September 30 prior to the beginning
of the trapping season.
brotal flow for the October immediately preceding the beginning of the trapping season.
CTotal flow for the year beginning January l (in the middle of the trapping season) and ending
December 31 .
dTotal flow for the year beginning October l just prior to the beginning of the trapping
season and ending September 30.
eTotal flow for January occurring during the trapping season.
fDegrees of freedom determined by number of years of compatible data.
gStatistical significance (p = .05) of correlation. Snedecor and Cochran 1967.
hstatistical significance (p = .01) of correlation. Snedecor and Cochran 1967.
I ---~1
w
CX>
Table 16. Correlation coefficients of linear regression analysis of number of beaver caches related to
flow data on the Bighorn, Tongue, and Yellowstone rivers.
Time of Flow
Degrees
Location of of
September/Augustb Gaging Station Freedoma Previous Water Year February/Januaryb June
YELLOWSTONE RIVER
At 3illinns 4 0.552 -0.993c 0.287 -0.471
At Miles City 10 -0.3fi4 -0.488 -0.329 -0.588d
At Sidney 10 -0.267 -0.318 -0.399 -0.316
TONGUE RIVER
At Mouth 9 0.127 0.470 0.092 0.265
BIGHORN RIVER
At Mouth 4 0.243 -!l.329 -0.001 0.582
rlOTE: All coefficients not irlentified by footnotes cord were not significant.
aDegrees of freedom--number of years of population data minus one.
bFor the Yellowstone River calculations, February and September flows were used; for the Tongue
and Bighorn calculations, January and Auqust flows.
CSignificance level (p = .01).
dSignificance level (p = .05).
250
II> 200 "' ""' u
0 u
~
CD >
0
"' (D -w 0 150 "' ~ .,
.c
E
::J z •
I
I
I
I
I
I
I
I
I ·•
I
I e I
I
I
I
I
e I -¢-
1
I
I
I
I
I
I + I
I
I
•
100
•
+
·.
125. 150
Flow (m 3/sec)
· .
• February
-------• June (xiO)
................. -¢-September
175 200 225
Figure 17.. Beaver cache count vs. recorded flows of the Yellowstone River at Oi11ingo
in February, June, and September.
~-~
l :'
/
"' 01 .c; ...
0 u
~
01 > 0
01
<D -0
~
01 .c
E
::> z
100
90
80
70
60
50
40
30
20
10
0
0
I
I
I
I
I
I
I •
"\
I
I
I
• I
I
• 1-9.•
I
t
I
I
I
I • • I
I
I
I
I
I
I.
I
I
50 100
-¢-•
•• •
150
• February
----• June ( •10)
........... -¢-September
•
•
200
-¢-•
.-¢-
.... -¢-
250
•
300 350
Fiqure 13. Beaver Cilche count vs. recorded flm·1s of the Yellm~stone
River at r~iles City in February, June, and September.
TRAPPING INCOME
Nearly $215,900 was introduced into the area economy from the sale of
pelts by 1 icensed trappers in the 1973-74 season (table 17). (No 1 icense is
needed to trap species not officially classified as furbearers--see discussion
of classifications on page 15. The value of the pelts trapped by unlicensed
trappers is not known.) The average licensed trapper in the study area
realized $685. Of this average, mink, muskrat, and beaver pelts accounted for
27 percent; beaver alone accounted for 20 percent. Economically, the most
important species was fox (26 percent of the total value of pelts), followed
by bobcat (24 percent).
40
·'
----·· ----~------------------------------------------------~
TARLE 17. Total dollars per species and average dollars realized ~er trapper of each species durina the 1973-74 fur
trapping season in Fish and Game ~eoions 5 and 7 . ..
Region 5 Reaion 7 Study Area
Total Value Average Income Total Value Averane Income Total Value Average Income
of Pe ltsa Per Trapper gf Of Peltsa Per Tranner of of Peltsa Per Trapper of
($} Each Species ($} (~) Each Speciesb($} ( s) Each Speciesh(S)
Beaver 21'1,15R.n2 215.fif) 14,561,52 166.67 4(,720.14 191. 1 a
'1uskrat 6,538.00 50.20 1,389.96 25.7~ 7 ,9?.7. Qfi 37.97
'link 3,560.34 a7.33 3.~9A.fi6 6B.63 7,059.nn 57.98
Weasel 3n.fin 1. 2fi 37.80 1. 71 58.~0 l.d9
Bobcat 21,728.07 2qa.A8 29,833 .n9 419.R3 51,561.16 357.lli
Skunk 3,768.00 24.80 2,850.75 31.28 6,618.74 28.04
Coyote 9,329.62 120.85 8,674.45 156.82 lil,004.07 138.84
Raccoon n,an. 75 8R.73 8,162.81 81.71 21 ,F,4f). 56 85.22
Badoer 745.31'1 17.27 1,99s.as 30.21 2.7~0.83 23.74
Fox 16,670.94 15~.35 38,597.66 4nq_ga 55,7.68.60 2ilfl.l7
Canada Lynx 1,998.97 310.19 289.48 lfJ8.56 2,288.45 209.38
TOTAL 116,006.29 633.9lc 109,1191.63 832.5lc 215,897.92 6R5.39c
aNumber trapped x avera~e pelt price.
bAveraoe catch per trapper x average pelt price.
cThese totals were derived by dividino the total value of pelts by the total nu~bers of licensed
traooers (183 in Region 5, 13< in Reaion 7, 315 in the study area).
Percentao e
of Total
Value of Pel
19.8
3.7
3.3
0.03
23.9
3. 1
R.3
10.0
1.3
25.6
1.1
ts
Since the 1960-61 season, beaver have been the most economically impor-
tant of the primary species studied. The sale of beaver pelts has generated
an average annual income of $193 per beaver trapper in Fish and Game Region 5
and $200 per beaver trapper in Region 7 (table 18) since that season. Mink
followed with $74 and $88 per mink trapper in Regions 5 and 7, respectively.
Muskrat trappers realized an average of $29 each in Region 5 and $20 each
in Region 7.
Since 1973-74, the number of trappers in the study area has decreased by
nearly 20 percent (table 19). The number of trappers living in towns situated
on the mainstem of the Yellowstone has decreased by 10 percent, although
trappers in that category have grown from 62 to 69 percent of all trappers
living within the study area. In 1975-76, 203 persons bought trapping licenses.
Twenty percent (40) of these ·live in Billings.
From these data it appears that most of the trappers are located in Fish
and Game Region 5, most live on the mainstem of the Yellowstone, and more live
in Billings than any other single location.
42
... w
----
TABLE 18. Total dollars per ~pecies and avcr<1ge dollars realized per trapoer per species in Fish and Game Regions 5 and 7, 1960-7.:1.
BEAVER mr~K MUSKRAT
.. ~~gion 5 Region 7 RefJiOn 5 Rfgion 7 Region 5
Total Value Average Total Value Average Total Value Average Total Va ue Average Total Value Average
of Peltsd Income of Peltsil Income of Peltsa Incone of Pelts lncor.-e of Pelts Income
(S) Per 1 rapper ( s) Pr.r Tri!p!JCr ( S) Pet" Traprcr ( $) Per Trapper (S) Per r,·appcr
of t.•uch of e<1ch of each of cuch of eac~1
Season speciesb(S} speclesb(S) speclesb(~) soec iesb( S) soec iesb( S)
1960-61 23.324.00 235. 72 14.239.00 261.82 II ,412. 12 124.15 1 ,660. 36 47.55 I ,34~. 50 14.44
1961-62 16,569.00 11:10.68 9,!)03.00 140.35 7.366.42 70. 14 2.240.60 65.90 3.693.60 34.20
1962-63 21,462.00 291. 27 17.283.00 313.89 11 ,511. 50 124. 12 8,830.95 252.56 6.708.42 70.50
1963-64 7,/95.00 120.98 5.528. 77 118.14 16.555.40 !66. 91 5.821. 76 155.04 2.995.74 32./5
1964-65 6.!04.70 127.40 2.!63.84 39.06 7 .005. 63 74.72 2 .219.14 92.22 2. 340. ?2 23.55
1965-66 5.052.84 132. 72 13.433.74 336.48 9.661.08 97.22 2.686.36 103.22 2.669.65 36.59
1966-67 3.901.79 I 55. 97 5.234. 0& 1 37. 48 5.905.20 72.96 1.351.25 64.63 I ,412.43 18.56
1967-63 11.102.07 173. 29 7.522.15 20&.78 3.283.38 45.29 1,394.64 58.97 49C. 00 7.32
1968-69 13.332.81 216.55 U,924.38 190.90 il,204.20 79.17 1 .921. 92 92.09 1.131.63 !6.82
1969-70 16.999. 50 19&.35 8.805.10 153.53 3.640.38 44.87 1 .659. 34 61.26 !.905. 30 19.53
1970-71 [},977.36 179.93 3.108.93 96.99 1 ,053. 15 24. 78 612.75 35. 40 959.04 16.80
1971-72 11,531.35 185.50 [J '101. 98 236.43 1 ,069. 26 21.08 587. 40 32.31 1.539.73 23.75
1972-73 28,101.96 243.97 24,391.96 291. 99 2,343.09 JJ.BJJ 3.554.90 102.51 4.!!0.03 37.54
1973-74 23.158.61 215.60 14.561.52 !66.67 3,560.34 47.33 3.493. 66 63.63 6.530.00 50.20
AVERAGE 14,915.29 193.21:1 10,200.~0 199.53 6,326.66 73.94 2.717.93 83.03 2,703.43 29.12
a/lumber trapped -. average pelt price.
bAverage catch per trilpper x average pelt price.
"eg1on'
Total Value Average
of Peltsa Income
! I) Per Trapper
of each
speciesb(S)
192.60 6.66
557.76 19.92
972.04 21. 13
1,096.00 24.88
!46. 73 8.24
639.34 31.99
85.80 5.35
227.88 7.99
984. 20 33.74
1,105. 28 27.28
335.67 15.75
348.74 14.34
2,419.22 43.07
!.389.96 25.74
750.12 20.47
TABLE 19. Residences of Yellowstone River Basin trappers.
1973-74 1974-75 1975-76
Number of Number of :~umber of
Resident Resident Resident
Trappers % Trappers " Trappers % "
MAINSTEM TOWNS
Bi 11 ings 42 17 56 23 40 20
Big Timber 22 9 22 9 18 9
Miles City 17 7 14 6 14 7
Glendive 15 6 14 6 12 6
Forsyth 11 4 10 4 12 6
Columbus 11 4 8 3 4 2
Laurel 7 3 5 2 11 5
Hysham 5 2 7 3 6 3
Others a 25 10 22 9 23 11
TOTAL 155 62 158 65 140 69
TRIBUTARY TO\-JNSb 96 33 85 35 63 31
REGION 5 157 63 169 70 135 67
7 94 37 74 30 63 33
TOTAL 251 100 243 100 203 100
aTrappers were resident in 16 "other" mainstem towns in 1973-74, 12 in
1974-75, and 13 in 1975-76.
bTrappers were resident in 39 tributary towns in 1973-74, 32 in 1974-75,
and 27 in 1975-76.
44
I
'
PROJECTIONS OF FUTURE USE
In order to adequately and uniformly assess the potential effects of
water withdrawals on the many aspects of the present study, it was nece~sary
to make projections of specific levels of future withdrawals. The methodology
by which this was done is explained in Report No. 1 in this series, in which
also the three projected levels of development, low, intermediate, and high,
are explained in more detail. These three future levels of development were
formulated for energy, irrigation, and municipal water use. Annual water
depletions associated with the future levels of development were included
in the projections. These projected depletions, and the types of development
projected, provide a basis for determining the level of impact that would
occur if these 1 eve 1 s of deve 1 opment were carried through.
IMPACT OF YELLOWTAIL DAM ON BIGHORN RIVER
Reservoirs have the potential for causing the most severe detrimental
effects on furbearer.populations, especially beaver. Settling out of sediments,
which results in channel degradation, and elimination of peak flows, which
greatly reduces island-forming processes, are the primary factors involved.
As a part of this investigation, aerial photos taken prior to the
construction of Yellowtail Dam were compared with photos taken after its
construction in order to determine what geomorphological changes had
taken place. The methodology and specific results of that study are given in
Report No. 2 in this series, The Effect of Altered Streamflow on the Hydrology
and Geomorphology of the Yellowstone River Basin, Montana.
Extensive, predictable changes in the structure of the Bighorn River
were revealed. The number and area of island gravel bars were substantially
reduced. A 77-percent loss in gravel bar area was recorded, The highest
losses were in the section closest to the dam, progressing to the lowest loss
in the section farthest from the dam. Overall, twenty-three percent of the
area of vegetated islands was lost. The number of islands, an indicator of
prime beaver habitat, was reduced from 414 to 287, a 31-percent reduction.
Combination of small islands into large islands eliminates the intermediate
waterways as locations for beaver caches, dams, and lodges. Joining of islands
to t~e mainland has the same effect. Even though the total riparian area
rema1ns relatively stable, the quality is greatly reduced for wildlife habitat.
When islands become part of the mainland, they become accessible to man and his
livestock, and their value as habitat is degraded as protective and escape
cover is lost. Controlled flows also encourage clearing of the land for
agricultural purposes, which is detrimental to many forms of wildlife,
including furbearers.
45
POTENTIAL IMPACTS OF ALTERED STREAMFLOWS ON FURBEARERS
The impact of altered streamflows on beaver and other furbearers can be
direct or indirect. Exact predictions of population declines or increases
would be subjective at best. Under any scenario on any river the' following
statements will generally hold true.
Reduction in flows during winter months can result in beaver caches and
muskrat feed beds freezing, making them inaccessible to use. Entrances to
lodges and bank dens may become exposed, making the furbearer vulnerable to
predation, or frozen shut, meaning death by starvation.
Increased winter flows could wash away food caches, forcing the furbearer
to constantly expose himself to the elements and to predators in order to obtain
food. It seems advisable, in the interest of furbearers, to maintain stable
flows from October, when beaver and muskrat begin construction of their food
caches, through March or April, when spring ice break-up is complete.
Low flows in early fall apparently stimulate beaver into building dams
(Wilsson 1968). Normally, beaver dams would be impossible to construct on
the Yellowstone, Tongue, or Bighorn rivers except in portions of braided
channel sections. Extremely lowered flows would encourage dam building by
beaver for protection and escape from predators. This activity would enta i 1
extensive additional cuttings of cottonwood trees and willow stands, incurring
several effects. First, it would decrease the available food supply for beaver.
Second, it would weaken bank resistance to erosion by high water du~ing
runoff periods. Third, it would reduce habitat for other wildlife species,
including deer, game birds, song birds, and raptors, which use cottonwoods and
willows for nesting, perching, and protective cover.
Indirect effects are probably more important than direct effects in the
long run. The most important of the indirect effects of streamflow alteration
is that related to channel morphology. Due to operation of reservoirs,
regulated rivers lose peak flows, the primary influence in formation of new
islands and gravel bars. ·The reservoirs, through deposition of sediments in
the reservoir, release clear water downstream, resulting in channel degradation.
This degradation results in the elimination of existing islands and gravel
bars. Then, with no new islands and gravel bars being formed and existing
ones being lost, plant succession can continue through the seral to climax
stages. Willow is usually the first seral stage to occupy areas of recent
alluvium (Hawk and Zobel 1974). However, as finer textured sediments are
deposited by successive lower-stage flooding (the results of lower flood
peaks), the soil becomes finer textured and the deoth to the water table in-
creases. When the flood plain is elevated beyond the normal flood level,the
plant communities develop toward climax,and willow, the primary beaver food
source in this area, is replaced by mature cottonwood-grassland vegetation.
Hawk and Zobel (1974) reported that willow associations were not common in
their study area, probably because of recent moderation of streamflow by
upstream reservoirs.
46
I
1
Beaver are almost totally dependent on the river for life functions. Mink
and muskrat, while living in proximity to water, are either able to move away
.from the river or actually prefer to live in marsh habitat and thus are not
as dependent on the Yellowstone or its tributaries for survival as are beaver.
River otter are dependent upon the fish population and other unknown factors
which seem to 1 imit otter numbers more than does the fish population. There
are few otter inhabiting the study area.
The Yellowstone River supports a higher density beaver population than
does either the Tongue or Bighorn rivers, both of which have major reservoirs.
The braided sections of the Yellowstone, with many islands and abundant
willow and young cottonwood stands, provide the best beaver habitat. The
poorest habitat consists of only one water channel with few or no deciduous
trees or shrubs. Recent historical peaks in population numbers seem to
have occurred in the early 50's and middle 70's. The present peak is the
highes·t since records have been kept.
Fur harvest studies indicate that beaver pelt prices have no effect on
the number of beaver trapped, suggesting that beaver trappers are as interested
in recreation as in profit. The two Fish and Game Regions in the study area
apparently have nearly equal numbers of beaver. Region 5 had more beavers
trapped and more beaver trappers, but region 7 had a higher catch per trapper,
a statistic which may be more indicative of population levels than the others.
Mink pelt prices were significantly related to the number of mink trapped
throughout the study area. Region 5 apparently has more mink than Region 7
because it showed more mink trapped, more mink trappers, and a higher average
catch per trapper, even though Region 7 had a higher average pelt price.
Muskrat pelt price, like that of beaver, was not related to the number
of muskrats trapped. Region 5 apparently has more muskrats than Region 7
because it showed the most trapped, the most trappers, and the highest catch
per trapper.
Examination of beaver caches built on the Yellowstone, Tongue, and Bighorn
rivers in 1975 revealed that willow was the beavers' primary food source.
Beaver preferred to build their caches in braided sections of the river and
onstream even under the pressure of high population levels. Mixed cottonwood
and willow stands were adjacent to tne majority of beaver caches, perhaps
reflecting the beavers' penchant for building caches next to areas with
relatively high banks to provide preferred bank den entrance locations.
Trapping contributed nearly a quarter of a million dollars ($215,900) to
theincome of local licensed trappers in the 1973-74 season. The average
trapper realized $685 that season,of which beaver, mink, and muskrat accounted
for 27 percent. Beaver, the most financially important of the water-related
furbearers, accounted for 20 percent of the individual trapper's trapping
47
income. Most of the trappers in the study area live in Fish and Game
Region 5, most live on the mainstem of the Yellowstone, and more live in
Billings than any other single location.
The numbers of beaver, mink, and muskrat trapped in Fish and Game Regions
5 and 7 were generally negatively related to flows of the Yellowstone River
at Billings and Miles City. In ~egion 5, the beaver relationships were signif-
icant (p = .05), but even the highest relationship was less than 40 percent
attributable to flow. Mink relationships were generally negative and insig-
nificant; as mentioned earlier, mink are not closely tied to the river ecosystem.
Muskrat relationships were negative in Region 5 and positive in Region 7.
Most of the muskrat were probably not trapped on the river.
Beaver population levels were negatively related to flow (significant at
p = .Ol) on the Yellowstone at Billings during the winter low-flow period.
With r2 = 0.99, almost all of the variation can be attributed to flow. With
that exception, the present natural flows in the Yellowstone and regulated
flows of the Tongue and Bighorn rivers do not seem greatly related to beaver
population levels. Thus, the greatest existing potential for direct influence
appears to be related to high flows during winter months, which may dislodge
caches, washing away the beavers' food supply, and flood lodges, causing the
beaver to die of exposure.
The impacts of altered streamflows on furbearers may be either direct or
indirect. Direct influences would occur as altered winter flo~1s froze up or
washed away food supplies. Low fall flows could trigger a dam-building
response, resulting in overharvesting of will 0\'1 and young cottonwood· trees,
which would lower the beavers' future food supply, lead to increased bank
erosion, and reduce protective cover for deer and other wildlife species. The
indirect effects, resulting from alteration of the morphology of the river
channel, would be most important in the long run. The primary indirect effect
would be the reduction and eventual elimination of willow stands and young
cottonwood trees, the beavers' food supply.
Reservoirs have the potential for causing the most severe detrimental
effects on furbearer populations. ~eport i~o. 2 in this series assesses the
geomorphological changes which have taken place in the Bighorn River since
the construction of Yello~1tail Dam. The number and area of gravel bars were
substantially reduced. The number of islands, an indicator of prime beaver
habitat, was reduced by 31 percent. The combination of small islands into
large ones and the joining of islands to the mainland both result in the
degradation of those islands as furbearer habitat.
48
I .
I
49
A-1
A-2
A-3
A-4
A-5
A-6
A-7
A-8
A-9
A-10
A-ll
A-12
TRAPPING DATA FOR BEAVER, MINK, AND MUSKRAT, 1954-74
FIGURES
Estimated number of beaver trapped state-wide and in Fish
and Game Regions 5 and 7, 1954-74 . . .
Estimated number of beaver trappers state-wide and in
Fish and Game Regions 5 and 7, 1959-74 .
Average beaver catch per trapper state-wide and in
Fish and Game Regions 5 and 7, 1959-74 . .
Average beaver pelt price state-wide and in Fish and
Game Regions 5 and 7, 1954-7 4 . . . .
Estimated number of mink trapped state-wide and in Fish and
Game Regions 5 and 7, 1954-74 . . . . . .
Estimated number of mink trappers state-wide and in
Fish and Game Regions 5 and 7, 1954-74.
Average mink catch per trapper state-wide and in Fish
and Game Regions 5 and 7, 1954-74 . . ..
Average mink pelt price state-wide and in Fish and
Game Regions 5 and 7, 1954-74 ...
Estimated number of muskrats trapped state-wide and
in Fish and Game Regions 5 and 7, 1954-74 ..
Estimated number of muskrat trappers state-wide and
in Fish and Game Re~ions 5 and 7, 1954-74 .
Average muskrat catch per trapper state-wide and in
Fish and Game Regions 5 and 7, 1954-74. . . ..
Average muskrat pelt price state-wide and in Fish
and Game Regions 5 and 7, 1954-74 . . . ..
51
Page
52
53
54
55
56
57
58
59
60
61
62
63
"0 .,
Q.
Q.
0 ... 1-... .,
>
0 ..
ID ,,, ~
N 0 ...
"' .0
E
" z
Region
Scale
5000
4000
3000
2000
1000
...
56-57
55-56 57·58
....
---..... ",. ················· ... it! .•.• " \ ······ · ..... ··· ..
61·62 67·68
...... ··
State-wide
Scale
State-wide
Region 5
Region 7
r. --·
I "-. l ·.
,_/ .....
.··
,,
I'
I'
71-72 73-74
50,000
40,000
30,000
20,000
10,000
Fioure A-1. Estimated number of beaver trapoed state-wide and in Fish and Game Regions
5 and 7, 1954-74.
-~------··--
"' ~ .,
Q.
Q.
0
~
1-
~ .,
>
0 .,
Ill
U1 w -0
~ .,
.0
E
" z
Region
Scale
140
120
100
80
60
40
20
54-55
Stole-wide
----Region 5
·············· Region 7
56-57
55-56 57-58
' ' \
59-60 61-62
' ' ' ' \
'
........
.............
', I
..... >1········ ........... .
.. ·········
68-69
67-68 69-70
. .. ...
I
I
I
I
I
I
I
I
I
I
State-wide
Scale
I
I
I
,
1400
I 1200
... ...
1000
800
600
400
200
72-73
71-72 73-74
Figure A-2. Estimated number of beaver trappers state-wide and in Fish and Game Regions
5 and 7, 1959-74.
65
60
55
50
45
~ .,
Q. 40 Q.
" ~
1-35
~ .,
Q.
.c 30 ... -"' " ..,. u 25
~
CD >
" 20 .,
CD
15
10
5
0
: :
! \
'
57-58 59-60 61-62
/\
.: \ : \ . \
\
64-65
63-64 65-66
68-69
67-68 69-70
State-wide
Region 5
Region 7
Figure A-3.
5 and 7, 1959-74.
Average beaver catch per trapper state-wide and in Fish and Game Regions
--~ -----------------------------------~~----------.. ~----~
"' "'
-..
~
0
0 ....
~ .,
u
~
Q. -.,
Q.
~ ., ,.
0 .,
ID
18
17
16
15
14
13
12
II
10
9
8
7
6
5
4
State-wide
----· Region 5
··············· Region 7
55-56 57-58 59-60
.:··;..,.~-....... ········
f /
" :,
... \ ... ,f .· -~--' ,: ... ..·· ··.~.~.~.~'. .. ·······.... .... ........ ./
61-62 63-64 67-68
,,
I ', ... ,
I "!• I .
1/ ........... ....
1 ......... ..
I
72-73
71-72 73-74
Fi!lure A-4. Average beaver pelt price state-wide and in Fish and Game Regions 5 and
7, 1954-74.
.., .,
a. a.
D
~
1-
.><: c
::!:
U1 -D "' ~ .. .c
E
:I z
Region
Scale
1400
1200
1000
800
600
400
200
I
I
I
I
I
I
I
I
. I
Stole-wide
Scale
State -wide
Region 5
Region 7
14POO
12POO
10,000
8000
6000
··.. I
·· ... I
~' I .. \ ........ ~,_,, r 4000
2000
\ '··., •. \\·...... "/'
·•••·•·•·•·••••.• ........ ,.,' ................ _ ................... .
.································...... •, ... ·········· .... ·· \ ...... ·········... . ... ···· ····.
·· .... ·· ···............ ·········......... ..
··· ......... ....
68-69
55-56 . 57-58 63-64 65-66 67-68 69-70 71-72 73-74
Figure A-5. Estimated number of mink trapped state-wide in Fish and Game Regions 5 and
7. 1954-74.
..
~
CD
Q.
Q.
0
~
1-... c:
::E
U1 -...... 0
~
CD .a
E
:::1 z
Region
Scale
140
120
100
'
80
' ' ' \
\
\
\
\
60 ..............................
40
20
55-56
\
,, A
," ....... .,"" \ ,------., ' ... " ',
\ ...
~,
' ' '"----"'
· .. ·· ..
···... ············· •... ·. . ..... ·····················
···········...... · ............ .
· .. .....
57-58 61-62
\
\
\
\
' ' ' ' ' \
\
\
\
\
···· .... ··············· ..... ··
67-68
..····· ...
69-70
State-wide
Scale
State-wide
Region 5
Region 7
··· ............ .
71-72 73-74
1400
1200
1000
800
600
400
200
Figure A-6. Estimated number of mink trappers state-~1ide and in Fish and Game Regions
5 and 7, 1954-74.
16
15
14
13
12
~ II CD a. a.
0
~ 10 1-
~
CD 9 a.
..<:
"' u -00 0 8 <.> ,.
c 7
:IE
6
5
4
3
2
, ' I
' ' I /" ', I
, ¥
I
I
I
,',' ,... ............................. .
··c~,
\ ,' ....
v ..........
'
\ !
\,/
59-60
68-69
63-64 65-66 67-68 69-70
State-wide
Region 5
Region 7
71-72 73-74
Figure A-7. Average mink catch per trapper state-wide and in Fish and Game Regions
5 and 7, 1954-74.
______________________________________ ._ __________ ._._._ __ .J
17
16
15
14
13
c;; 12
~
" 0 II ..,
~ ., 10 u
~
(J1 D..
"' 9 .,
D..
.... 8 c
:::E
7
6
5
4
3
~-
55-56 57-58
60-61
59-60
/'···· ...
I ,_\\-,, ----
/ v' \ ,
I \ '----~\\ ,, , \
\
\
\
\
\
\
\
' '
62-63 64-65
61-62 63-64 65-66
68-69
67-68
State-wide
Region 5
Region 7
, ,
I
I
I
I
I
I
I
I
I
I
I
I
I
, ,
, , ,
I
I
I
72-73
73-74
Figure A-8. Average mink pelt price state-wide and in Fish and Game Regions 5 and 7,
1954-74
"' 0
Region
Scale
9000
8000
7000
>.
II
I I
I I
I I
I I
I I
I I
I I
I I
I I
I I
I I
I I
• II
State -wide
Scale
State-wide
----Region 5
·············· Region 7
90,000
80,000
70,000
~ 6000 I I
I I
I I
I I
I I
I I
I I
60,000
a. a.
0
~
1-
0 5000
~ .... ..
::J
:IE -4000
0
~
CP
..0
E
::J 3000 z
2000
1000
I
I I
I
I
I
54-55
55-56
I
I
I
I
I
I
I
I
I
I I
I I
I I
I I
I
I
I
I
I
I
I
I
I
58-59 60-61 62-63
57-58 59-60 61-62 63-64
·········•····· .....
68-69
67-68 69-70
.... ......
71-72 73-74
Figure A-9. Estimated number of muskrats trapped state-wide and in Fish and Game Regions
5 and 7, 1954-74.
50,000
40,000
30,000
20,000
10,000
---· ·------------------------~--~---.~--------------L-_.W.~
Cl)
~ ..
0.
0. c
~
1--c
~ ><
Cl)
" 0'> :::;;:
.....
0
~
"' .c
E
" z
Region
Scale
140
120
100
80
60
40
20
·· .. ···.
· .... ·
.... ··· .. ··
54-55 56-57
55-56 57-58
······ ...
•
I '
I '
I '
I '
I '~
I ........ '
I '
I '
I ' ' I '
I ',
State-wide
Region 5
Region 7
I ', ........ -',
:· ........ ·
.......... . ......
······ ....
64-65
...
. .. ·
66-67
63-64 65-66 67-68
· ..... ... ...
71-72
State-wide
Scale
...... .....
73-74
1400
1200
1000
800
600
400
200
Figure A-10. Estimated number of muskrat trappers state-wide and in Fish and Game
Reqions 5 and 7, 1954-74
140
120
100
~ .,
Q.
Q.
c
~
1-80
~ .,
Q.
~ u -0> c
N <..> 60
c
~ ... ..
::J
~
40
20
State-wide
Region 5
Region 7
.. : .•. '· ••. ''----,,,_. ../\\'.. ... ....... -······· --.
. ·· ... .. .. ····... ',,'."' .... !,./ ', '--~·-:.·,.,·-::..~ .. -.... -..... ~ .. /-:.·-.:: .. ~ .. -..
.... ............... ..... .... .
............... ·........................................ ........... .... .......... ···· .·
55-56
58-59
57-58
64-65 66-67
63-64 65-66 67-68 69-70 71-72
Figure A-11. Average muskrat catch per trapper state-wide and in Fish and Game Regions
5 and 7, 1954-74.
~ ..
~
.!:!
0 ..,
CD ....
~
"' n.
w -CD n.
0
~
.>< ..
" :::;:
-----....--
2.50
2.00
1.50
1.00
.50
----
..............
54-55
55-56
Stole-wide
Region 5
Region 7
57-58 59-60
,
......... !
i
61-62
~ , ', ,
63-64 65-66
, .... , ...
If
l ,.
/ r.
//
(:,~ 1/ ,. ·.,, , ...
.. ····~~-~ ···-~-~-' .... ~ .....
... / '\, .. · I
\···· .... · .... ,'
' / ' / '
71-72
....
73-74
Figure A-12. Average muskrat pelt price state-wide and in Fish and Game Region 5 and 7,
1954-74.
B-1
B-2
B-3
B-4
B-5
B-6
B-7
TRAPPING CORRELATIONS AND REGRESSIONS, 1960-74
FIGURES
Beaver trapped vs. beaver trappers in Fish and
Game Regions 5 and 7, 1960-74 ........ .
Beaver trapped vs. average catch per trapper in
Fish and Game Regions 5 and 7, 1960-74 .....
Mink trapped vs. mink trappers in Fish and Game
Regions 5 and 7, 1960-74 .......... .
. . . . . . . .
Mink trapped vs. average catch per trapper in Fish
and Game Regions 5 and 7, 1960-74 ........ .
Mink trapped vs. average mink pelt price in Fish and
Game Regions 5 and 7, 1960-74 ........... .
Muskrat trapped vs. muskrat trappers in Fish and Game
Regions 5 and 7, 1960-74 .............. .
Muskrat trapped vs. average catch per trapper in Fish
and Game Regions 5 and 7, 1960-74 ......... .
65
Page
66
67
68
69
70
71
72
2800
2600
2400
2200
2000
1800 , .,
0.
0.
0 1600 .=
~ .,
> 1400 0 .,
CD -0 1200
~ .,
"' E
:I 1000 z
800
600
400
200
0
*
0
i •
•
I
I
I
I
I
I
I
I
I
I
I
I
I
• I
I
I
* I I
I
I
I•
•
I
*
I
-t * I I
I
I + ·~~· .:. I
• •
+ 4
* !· /
*
•
* ; I :*I ----. Region 5
·( I
; I * f I ; I
! I
' I ! I
" " 50
* Region 7
100 150
Number of Beaver Trappers
200
Fiqure B-1. Beaver trapped vs. beaver trappers in Fish
and Game Regions 5 and 7, 1960-74.
66
2800 I •
I
I
2600 I
I
2400 I
I
I
2200 I
I • I •
2000 I • ~ • I .., 1800 I ~ .,
ca. I ca.
0 I ~ • 1-1600 I ~
I .,
>
0 + Q) 1400 m ... I~ 0
~ 1200 I Q) I "" E I. + ::0 z 1000 ~ :I
.I~ •.:
' .. ~ 800 I
I • : ~ f .... · ~ 600 ----. Region 5
1 ... ~ ......... ~ Region 7
400 1..;
J·
·~ .f
200 .. ~
:"I
_.· I
0
0 10 20 30 40 50
Beaver Catch per Trapper
Figure B-2. Beaver trapped vs. average catch per trapper
in Fish and Game Regions 5 and 7, 1960-74.
67
... • ... ... ..
~
1-.. c
:I! -0
~ • ...
E
:::J z
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
0 10
*
*
:
: *
* + * l:~ *
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Figure B-3. Mink trapped vs. mink trappers in Fish and Game
Regions 5 and 7, 19fi0-74.
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Figure B-4. Mink trapped vs. average catch per trapper in
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Figure B-6. Muskrat trapoed vs. muskrat trappers in Fish and
Gil me Regions 5 and 7, l %0-7 4.
71
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Figure B-7. Muskrat trapped vs. average catch oer trapper in
Fish and Game Regions 5 and 7, 1960-74.
72
C-1
C-1
C-2
C-3
TRAPPING SEASONS AND RESTRICTIONS HI
DEPARTMENT OF FISH AND GAME REGIONS 5 AND 7, 1960-74
FIGURES
Trapping Districts within Region 5, 1960-61 through
1968-69 Trapping Seasons ............. .
TABLES
Opening and Closing Dates of Beaver, Mink, and Muskrat
Seasons in Regions 5 and 7, 1960-74 ....
Beaver Trapping Quotas in Region 5, 1960-69 ...
Restrictions on Beaver, Mink, Muskrat, and Otter
Trapping in Regions 5 and 7, 1960-74 ...... .
73
Page
74
75
76
76
\
NOTE: After the 1961-62 trapping season, District 52 was reappor-)
tioned to Region 7. See table C-2. I -----
I 53
54 t
0
I MUSSELSHELL
I
WHEATLAND I
I
_j
55 51
INDIAN
BIG HORN
CARBON RESERVATION ~
56
YELLOWSTONE ' )
WYOMING
NATIONAL PARK • (
Figure C-1. Trapping Districts within Region 5, 1960-61 through 1968-69 Trapping Seasons.
TI\BLE C-1. Ooenings and closinn dates of beaver, mink, and muskrat seasons in
Regions 5 and 7, 19n0-74.
BEAVER MINK MIJSKRAT
Openinq Closing Openina Closin{l Opening Closing
Year Date Date Date Date Date Date
REGION 5
1960-61 11110 4130 11110 12/31 11110 4/30
1961-62 10115 4/30 11110 12131 11110 4/30
1962-63 10115 4/30 11110 12/31 11110 4/30
1963-64 10115 4/30 11110 12/31 11110 11130
1964-65 10115 4130 11110 12131 11110 4/30
1965-61' 10/15 4/30 11110 12131 11110 4130
1966-67 10115 4/30 11110 12/31 11110 4130
1967-68 10115 4/3'1 11110 12131 11110 4/30
1968-69 10115 413() 11110 12131 11110 4f30
1969-70 11 I 1 413n 11/1 12/31 11 !1 4130
1970-71 11110 4130 11110 12/31 11110 4130
1971-72 11110 3131 11110 12/31 11110 3131
1972-73 11110 3131 11110 12/31 11110 4/~0
1973-74 11/10 3/31 11110 12131 11/10 4130
REGION 7
1960-61 11111) 4/30 11/10 12131 11110 4/30
1961-62 11110 4/30 11110 12131 11110 4/30
1962-63 11 I 1 4130 1111 12/31 1111 4/30
1963-64 1111 4/30 11 I 1 12/31 1111 4/30
1964-65 1111 4130 1111 12/31 11/1 4130
1965-66 1111 4/30 1111 12/31 1111 4130
1966-67 11/1 4/30 . 1111 12/31 11 I 1 4130
1967-68 11 !1 4/30 11 11 12131 11 11 4130
1968-6<l 1111 4/30 1111 12131 11/1 4130
1969-70 11 I 1 4/30 11 !1 12131 1111 4130
1970-71 11110 4/3() 11110 12/31 11110 4130
1971-72 11110 3131 11/10 12131 11110 3/31
1972-73 11/10 3/31 11110 12131 11110 4130
1973-74 11110 3131 11110 12/31 11110 4130
NOTE: Beaver, mink, and muskrat trapping during these seasons was affected by
quotas and other restrictions. See tables C-2 and C-3. ·
75
TABLE C-2. Beaver trappinq quotasa in Region 5b 1960-69c.
District in Region 5d
51 52e 53 54 55 55 57
1960-61 BOO 350 400 5f]f] 41)0 300 800
1961-62 8fl0 NL NL NL 500 250 800
1962-63 600 NL NL 500 300 NL
1963-64 600 NL NL 500 300 NL
l964-fi5 600 NL NL 500 150 200
1965-66 200 100 200 100 150 200
1966-67 200 100 200 100 150 200
1967-fiS 100 100 200 100 150 100
19613-69 150 100 250 100 150 100
NOTE: tiL; no limit
aEach trapoer could apply each year for assignment to only one district.
In those districts with set quotas, the limit per trapper was set by dividing
the beaver quota among the apolicants.
bof the two Fish and Game regions included in the study, 5 and 7, only
Reqion 5 had beaver ouotas during the years examined.
Cin the 1969-70 throuqh 1973-74 trapping seasons, no quotas were set in any
reqion east of the Continental Divide, including Region 5.
dReqion 5 was divided into numbered districts (51-57), each with a separate
headquarters and warden. Boundaries of these districts varied: see fiqure C-1.
eAfter the 1961-62 trapping season, district 52 was reapportioned to Reqion 7.
and the number 1~as dropped. See fiqure C-1.
Table C-3.
1960-61
1960-61
through
1973-74
1965-66
through
1968-69
1968-69
through
1971-72
1972-73
and
1973-74
Restrictions on beaver, mink, muskrat, and otter trapping in
Reqions 5 and 7, 196fl-74.
For this season only, beaver could be taken in Region 7 by either
trappinq or shootinq. In Region 7 for all other years investigated
and in Region 5 for all years investiqated, beaver could be taken only
by trappinq~
In all years investigated for this study, each trapper was allowed
to take and possess only one otter.
Closed to otter trapping: all of Region 5.
Closed to heaver trapping in Region 7: the Yellowstone River from
the new Mvf'rS bridqe downstream to the Highway 12 bridge at Forsyth.
Closed to otter trapping: the Yellowstone River from the Yellowstone
National Park boundary to the North Dakota border.
76
I.
1.
I
I,
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77
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central power study:
Billings, MT 80 pp.
Coordinating Committee. 1971 (October). North
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Rutherford, W.H. 1964.
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The beaver in Colorado -its biology, ecology, manage-
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49 pp.
Ryder, R.A. 1955. Fish predation by the otter in Michigan. Journal of
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78
·'•
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79
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