MOUNTAIN LION DATA ANALYSIS UNIT L-6
MANAGEMENT PLAN
GAME MANAGEMENT UNITS
15, 25, 26, 34, 35, 36, 43,44,45,47,444,471
NORTHWEST REGION
Prepared for:
Colorado Division of Wildlife
By:
John Broderick
Wildlife Biologist
Glenwood Springs, Colorado

November 2004

 DESCRIPTION OF DAU, HABITAT AND PAST MANAGEMENT
Location
DAU L -6 is located in west-central Colorado just west of the Continental divide. (Figure
1) I- 70 bisects the DAU from east to west. The north-west portion of the DAU contains

Figure 1
all the lands that drain into the lower Colorado River from Gore canyon to Glenwood

2

 canyon (GMU’s 15, 25, 26, 34, and 35).
The south- western potion of the DAU
comprises of the area drained by the Roaring Fork, Crystal, and Frying Pan Rivers
(GMU’s 43, 44, 47,444 and 471). The south-eastern portion of the DAU includes the
area drained by the Eagle River including Gypsum creek and Brush creek (GMU 44); the
Lake creeks and Homestake creek (GMU 45). Finally the north-east portion of the DAU
includes the west half of the Gore Mountains, Red and White Mountain and the Piney
river drainage (GMU 36).
The total area of L-6 is approximately 11,978 square kilometers. (4624 sq. miles). The
DAU is approximately 74% public land, 25 % private property, and 1% state land board
(Figure 2).

L-6 Land Status

SLB
1%

PVT
25%
PVT
DOW

DOW
0%
FS
56%

BLM
FS

BLM
18%

SLB

Figure 2
Bureau of Land Management (BLM) land represents 18 % of the public land with the
United States Forest Service managing the other 56 %. The private lands are
concentrated along the I- 70 corridor and along the Roaring fork and Crystal rivers.
Habitat
This DAU contains a complete range of mountain lion habitat. The lower canyons (5700
ft. elev.) and side drainages of the Colorado River from Canyon Creek to Gore Canyon;
the lower elevations along the Piney River; and the lower drainages below Red and
White Mountain is considered to be excellent terrain for mountain lion in that it is
bisected by numerous canyons and rugged terrain that meets year around lion
requirements for food and cover. The south side of the DAU contains some excellent
mountain lion habitat in the canyons on the lower Roaring Fork and Crystal River
drainages, lower Frying Pan River, and the lower Eagle River area (south of the Eagle

3

 River from Dotsero to the town of Eagle). At the other extreme is the high elevation
spruce fir sub-alpine fir and alpine tundra habitats of the Gore, Sawatch and Elk
mountain ranges which puma infrequently occupy.
Mountain lion are primarily associated with the lower elevation habitats in the DAU
among the rocky, steep canyons. The vegetation in these areas varies in relation to
altitude and aspect, but is typical of high desert vegetative communities. Pinion-juniper
woodlands dominate the landscape. Gamble's oak, serviceberry, mountain mahogany
interspersed with aspen and Douglas fir pockets are common in the unit. Mountain
shrub- sagebrush communities are typical in the medium elevations of the DAU. The
higher elevations contain spruce-fir and alpine tundra habitats
Human development
With the exception of the Interstate 70 corridor, the northern portion of the DAU has not
experienced the tremendous growth in land development compared to other areas in the
mountains. There are a few small towns and communities that include Burns, Wolcott,
McCoy, State Bridge, Toponas, Yampa and Radium. The southern portion of the DAU
however, has experienced a tremendous growth in land development. Some of the
highest human densities in the mountains occur in this area along the I-70 corridor and
in the Roaring Fork Valley. Major towns in this part of the DAU include - Vail, Avon,
Eagle, Gypsum, Glenwood Springs, Carbondale, Basalt, Snowmass Village and Aspen.
Research shows mountain lions inhabit large geographic areas due to the innate
characteristics and social habits of the species. Therefore, this Lion Data Analysis Unit
(DAU) L-6 combines two previous lion DAU’s (L- 6 and L-10) into one large area.
Utilizing a geographically larger DAU area increases the probability that the boundaries
of the management area encompass the actual life processes of the puma population.
Increasing the geographic area to a size similar to the area in which the life history of
puma population unfolds increases the veracity of the base line data which the CDOW
collects. The larger geographic scale of analysis is especially appropriate for Puma
management in relation to: Analysis and monitoring of population trends, estimation of
lion and prey densities, assessment of management actions, and preservation of refuge
areas. Further, the dispersal of juveniles and the immigration of transients signifies the
importance of considering lion populations management on a regional basis (Logan, et
al. 1986).
MANAGEMENT HISTORY
Historically, this area supported a large mule deer population. Since the mid-1960's,
deer numbers have declined but have had a cyclic behavior. This area still supports
good populations of mule deer compared to other areas of the state. Elk populations
have been steadily increasing since the turn of the century. DAU L-6 contains three
entire Elk DAU’s (E-12, 15, 16), and a portion of E-6 (White River Elk herd). DAU L-6
contains five entire deer DAU’s (D-8, 13, 14, 43, 53).
Prior to 1965 mountain lions were an unprotected species in Colorado. Mountain lion
could be killed at any time and for any reason. In fact, bounties where paid for lion
carcasses. In 1965 mountain lion were classified as a big game animal in Colorado.
Thus, a license was required to hunt lions and annual seasons and quotas were
established. Until the early 1980’s the interest and participation in mountain lion hunting

4

 was minimal. Since the mid 1980’s the number of hunters in DAU L-6 has increased to
approximately sixty per year.
Harvest and Management Statistics
The CDOW has assembled pertinent management data going as far back as 1980.
Data includes harvest, quotas, success rates, and harvest by sex of animal. Similar
information is also available for animal damage control kills and other mortality such as
road kills.
Presently, season dates for lion hunting are from January 1st until March 31st and from
the 1st day after the close of the regular deer and elk seasons until December 31st. New
harvest quotas begin on January 1st of each year.
Mountain lion annual harvests as well as quotas have increased substantially over the
last 25 years. In the early 1980’s only 5 puma were harvested from the entire area
defined by L-6, but by the year 2000, as many as 20 lion where being harvested
annually. The most recent 5-year average for puma harvested in this DAU is 24 lion, with
the 10-year average harvest equaling approximately 22 lion. The percent of female lion
harvested has a 5 and 10 year average of 41%.
Populations
The L-6 lion population projection is based primarily on two factors; defining the area of
suitable lion habitat within the 4624 sq. miles of the DAU and applying a probable lion
density for that same area. Based on a comprehensive review of lion research literature,
Logan and Sweanor (2001) offer a range of lion densities observed on projects from
throughout the western United States. Given the similarities between Colorado and
states/provinces such as Wyoming, New Mexico, Alberta, British Colombia and Idaho,
densities were extrapolated from those studies to arrive at a low density estimate of 0.02
lions/sq.km. and a high density estimate Lion habitat within DAU of 0.046 lions/sq.km.
In almost all cases in Colorado, lion habitat overlaps with the range of their principle food
source, mule deer. However, in western Colorado, elk provide an additional prey based
for lion. Anderson (2003) documented elk being a significant prey item, especially for
adult male lion. Recently, elk research projects conducted by CDOW in the Rifle area
and field observations by CDOW personnel and outfitters confirm elk kills by lion are not
unusual.
The lion population estimate for DAU L-6 was determined by delineating the area of the
DAU classified as winter range for deer, elk and bighorn sheep. A high lion density
estimate was attributed to this area (1617 sq. miles). The area of the DAU above 10,500
feet (1517 sq miles) was excluded from the analysis because puma infrequently occupy
or utilize these high mountain habitats, where snow accumulations limit the presence of
a prey base. A medium lion density was attributed to the area of the DAU that was
below 10,500 feet in elevation, was not considered winter range, but still contained lion
habitat (1169 sq. miles). Finally a low lion density was attributed to the remaining habitat
within the DAU (320 sq. mile). The calculated population projection from this analysis of
available lion habitat (Figure 4) in L-6 was determined to be approximately 301 lion.

5

 Figure 4
Population Management Alternatives and Outcomes
Harvest Potential
Logan and Sweanor (2001) and Ross and Jalkotzy (1992) reported that kittens, or
dependent young, comprised approximately 33-34% of the total population. Given this
information, an estimate of the huntable population of lion in the Dau would be 202 lion.
(301* 33%= 99 juveniles, 301-99=202 independent lion).
Using the portion of the
projected population that are independent (adults and sub-adults) lion, an acceptable
level of mortality within a DAU can be estimated. An annual harvest of 8-15% of the
total legal population (adult and sub adult) would be considered biologically sustainable
(Logan and Sweanor (2001). Table one illustrates the various harvest scenarios for L-6.
Annual
Rate

Mortality

8%

12%

15%

18%

20%

Hunter Harvest

15

23

29

35

39

Non-hunt Mort.

1

1

1

1

1

6

 Total Mortality

16

24

30

36

40

Table 1. Number of lion harvested at variable mortality rates.
Cougar populations appear fairly resistant to moderately high levels of harvest as
indicated by Anderson’s (2003) research. The caveat being, that “adjacent populations
facilitate recovery through immigration and that adult female survival provides female
recruitment” (Anderson 2003).
Anderson (2003) also stated, “The most likely factor to inhibit cougar population
reduction from harvest is limited hunter access creating local refuges. In these
situations, inaccessibility will dictate the degree of resiliency in that population to hunter
harvest…”
Refuge areas
A geographic review of Dau L-6 shows five wilderness areas (Hunter Frying pan, Holy
Cross, Maroon Bells, Flattops, and Gore) totaling approximately 511 square miles; one
BLM area (King Mountain) managed for non – motorized recreation totaling 19 square
miles; and another seventeen parcels, totaling 300 square miles, of roadless public land
identified in the White River National Forest Plan 2002.
Large portions of the
wilderness areas are suitable habitat for mountain lion, and much of the acreage
identified in the White River Forest Plan, as roadless, are mid to low elevation lands that
also contain good mountain lion habitat.
Monitoring
Population monitoring will be accomplished primarily from data collected as a part of the
mandatory check of lions harvested. The estimated age of the animal will be determined
using techniques outlined by Anderson and Lindzey (2000). Specifically, priority should
be given to evidence of previous lactation, annuli aging of premolars, presence of a
canine ridge and presence or absence of fore leg bars (Anderson 2003).
Anderson (2003) in his study of the sex and age characteristics of cougar populations
documented that, “population decline followed predictable removal patterns of the more
vulnerable/ abundant classes until the least vulnerable class, adult females were most
abundant in the harvest”, and that, “Moving from harvests consisting primarily of sub
adults to adult males and finally to adult females suggests previous population decline”
Therefore, if the percentage of adult females in the harvest begins to increase, and the
average age of females in the harvest begins to decline then harvest restrictions would
be warranted until male lions and sub adult lions comprised the majority of the harvest,
indicating a recovering lion population.
Game Damage Objective
Figures 5 and 6 illustrate the number and dollar amount of game damage claims over
time in DAU L-6. The 5-year average for the number of mountain lion claims is 2. The
10-year average is 3 claims. The 5-year average for the dollar amount paid for mountain
lion damage is $905.00 dollars. The 10-year average is $2,179.00 dollars. In certain

7

 years the damage to domestic sheep by lion can approach $10,000.00 dollars.

Number of Claims Paid
10
# of claims

8
6
4
2

19
79
19
81
19
83
19
85
19
87
19
89
19
91
19
93
19
95
19
97
19
99
20
01
20
03

0

Years

Figure 5

Dollar amount paid for Mountain Lion damage
10000
9000
8000
7000
6000
5000
4000

dollars

3000
2000
1000

19
79
19
81
19
83
19
85
19
87
19
89
19
91
19
93
19
95
19
97
19
99
20
01
20
03

0

years

Figure 6

Game damage will be managed by targeting offending lions on an as needed basis. The
CDOW has an effective working relationship with Wildlife Service including a contract for
annual damage control assistance.
Most claims can be minimized and or mitigated through effective communication with the
livestock operators, landowners and CDOW.
Monitoring of game damage claims will occur on an annual basis. Significant increases
in game damage may induce harvest objective changes. Most likely the GMU quota will

8

 be amended to focus harvest in the area of damage.
Key Management Issues – An issue raised by the publics reviewing mountain lion
management in Colorado has centered upon the ability of CDOW to manage cougar
populations in the context of a “metapopulation” As defined by McCullough (1996), “a
metapopulation is a population distributed in subpopulations across a set of suitable
habitat patches typically isolated in a matrix of unsuitable habitat, in which each sub
population in each patch has a non trivial probability of extinction. Anderson (2003)
investigated the genetic structure of cougar populations across the Wyoming basin to
include genetic samples from cougars as distant as southwest Colorado. The
conclusions of his research indicate that, “Cougars in the central Rocky Mountains
exhibit high gene flow and low structure presumably because high male dispersal
suffices to maintain connectivity between subpopulations”. Further, Anderson states,
“our findings in the central Rocky Mountains are more consistent with a large panmictic
cougar population exhibiting rapid interchange among subpopulations.”
CDOW believes that managing mountain lion populations on a large geographic scale
which incorporates refuge areas, and maintains healthy sex and age ratios among the
lion populations will be sufficient to preserve genetic viability among Colorado’s puma
population.
Another management issue raised by the general public concerns mountain lion –human
interactions. There is the potential that as the human population increases, along the I70 corridor and in the Roaring fork valley the potential for human –mountain lion
interaction will increase.
Preferred Management Strategy – Stable increasing
The preferred management strategy for L-6 is to maintain an acceptable annual mortality
rate, including hunting and non-hunting, in a range between 8% and 15% of the huntable
population. This rate of removal would maintain or possibly increase the population of
mountain lions. Quotas will be determined annually based on harvest success and other
mortality factors. The long-term goal in L-6 is to maintain a healthy sustainable puma
population while providing continued opportunity for sport harvest, minimizing humanlion conflicts and mitigating domestic livestock loss by lion.
Literature Cited
Logan, K. A. and L. L. Sweanor. 2001. Desert puma: evolutionary ecology and
conservation of an enduring carnivore. Island Press. Washington, DC
Logan, et al. 1986).
Zinn, H. C. and M. J. Manfredo. 1996. Societal preferences for mountain lion
management along Colorado’s Front Range. Human Dimensions in Natural Resources
Unit Report No. 28, Colorado State University, Fort Collins, CO.
Anderson, C A. Jr. 2003. Cougar Ecology Management and Population Genetics in
Wyoming. Ph. D., Dissertation Department of Zoology and Physiology.
Anderson, C.R., and F.G. Lindzey. 2000 A photographic guide to estimating cougar age
classes. Wyoming Cooperative Fish and Wildlife Research Unit. Larimie, Wyoming,
USA.

9

 Ross, P.I., M.G. Jalkotzy. 1992. Characteristics of a hunted population of cougars in
southwestern Alberta. Journal of Wildlife Management 56:417-426

10

 L-6 DAU Plan Amendment July 2011
Because of the increasing number of lion sightings and livestock/pet/bighorn sheep conflicts in
lion DAU L-6, Area personnel believe that the lion density in the DAU is higher than estimated previously
in the original 2004 DAU plan. The lion population estimate and harvest objectives are reexamined in
this L-6 DAU plan amendment.
Lion population estimate
In the current (2011) estimate, we included areas up to 11,500 feet elevation as potential lion
habitat and we used averages of population densities and age/sex composition from published
demographic studies of mountain lions in multi-prey systems (Table 1; Seidensticker et al. 1973, Logan
et al. 1986, Ross and Jalkotzy 1992, Spreadbury et al. 1996, Logan and Sweanor 2001, Cooley et al. 2009,
Robinson and DeSimone 2011).
Areas within deer, elk, and bighorn sheep winter range that are below 11,500 feet elevation
(4,150 km2) were considered high quality lion habitat and were assumed to have a lion density of 4.5
lions/100km2. Areas not within winter range and up to 11,500 feet elevation (4,631 km2) were
considered medium quality lion habitat with an assumed lion density of 3.5 lions/100 km2. Areas
classified in the Basinwide habitat cover type map as developed, agricultural, rangeland, and other open
habitat types (values 1-6, 9-11, 12, 13, 19, 20, and 96-99) that were below 11,500 feet (762 km2) were
considered low quality lion habitat with an assumed lion density of 2.0 lions/100 km2. Areas classified as
water (value 114) in the Basinwide map, as well as areas above 11,500 feet, totaled 871 km2 and were
considered non-habitat for lions. See Figure 1 for a map of lion habitat quality in L-6.
These densities, extrapolated to the foregoing areas, yield a projected population of 365 total
lions. Assuming 61% of the population to be independent (adult and subadult) lions (Table 1), an
estimated 223 independent lions are available for harvest.
Harvest objective
Based on the estimate of 223 adult and subadult lions in the population, at an 8-15% total
mortality rate, which is described in the DAU plan as an assumed sustainable mortality rate for
stable/increasing management, 16 to 31 lions (average of 24) could be harvested annually (Table 3).
Under a more liberal harvest strategy, assuming a total mortality rate of 12-15%, the annual harvest
would be 24 to 30 lions (average 28) (Table 3).
To attempt to address localized lion conflict issues by managing the overall DAU population size through
harvest, we chose the more liberal harvest mortality rate of 12-15% as a harvest objective. Whether this
approach will lead to fewer lion conflicts is yet unknown. Therefore, we will monitor the level of human
conflicts and game damage claims on an annual basis. Sex and age composition of the harvest will
continue to be monitored to determine whether an increase in harvest results in a change in the age
and sex composition of harvest, which may be suggestive of changes in population size (Anderson and
Lindzey 2005).
Page   1

 Literature Cited
Anderson, C. R. and F. G. Lindzey. 2005. Experimental evaluation of population trend and harvest
composition in a Wyoming cougar population. Wildlife Society Bulletin 33:179-188.
Cooley, H. S., R. B. Wielgus, G. M. Koehler, H. S. Robinson, and B. T. Maletzke. 2009. Does hunting
regulate cougar populations? A test of the compensatory mortality hypothesis. Ecology
90:2913-2921.
Logan, K. A. and L. L. Sweanor. 2001. Desert Puma: evolutionary ecology and conservation of an
enduring carnivore. Island Press, Washington, D.C., USA.
Logan, K. A., L. L. Irwin, and R. Skinner. 1986. Characteristics of a hunted mountain lion population in
Wyoming. Journal of Wildlife Management 50:648-654.
Robinson, H. S. and R. M. DeSimone. 2011. The Garnet Range Mountain Lion Study: Characteristics of a
Hunted Population in West-central Montana. Final report, Montana Fish, Wildlife & Parks,
Wildlife Bureau, Helena, MT. 102 pp.
Ross, P. I. and M. G. Jalkotzy. 1992. Characteristics of a hunted population of cougars in southwestern
Alberta. Journal of Wildlife Management 56:417-426.
Seidensticker, J. C., M. G. Hornocker, W. V. Wiles, and J. P. Messick. 1973. Mountain lion social
organization in the Idaho Primitive Area. Wildlife Monographs No. 35. 60 pp.
Spreadbury, B. R., K. Musil, J. Musil, C. Kaisner, and J. Kovak. 1996. Cougar population characteristics in
southeastern British Columbia. Journal of Wildlife Management 60:962-969.

Page   2

 Location

Area
km2

Adult M

Adult F

Subadults

Kittens

% kittens

low
2

high
6

low
0

high
5

low
1

high
7

low
17%

high
33%

mean
25%

Total lions/100
km2
low high mean
1.2 4.0
2.6

Source

Idaho

520

low high
3
3

Wyoming
Alberta

741
780

3
4

3
5

7
8

9
12

1
2

7
10

13
6

17
18

54%
30%

47%
40%

51%
35%

3.2
2.6

4.9
5.8

4.0
4.2

British
Columbia
New
Mexico (TA)
New
Mexico (RA)
Washington
(NE)
Washington
(Central)
Montana

540

1

2

4

4

2

4

11

11

61%

52%

57%

3.3

3.9

3.6

703

4

6

3

9

0

5

3

15

30%

43%

36%

1.4

5.0

3.2

11

6

16

1

5

6

23

30%

42%

36%

1.5

4.1

2.8

722

2.1

4.8

3.5

Seidensticker et al.
1973
Logan et al. 1986
Ross and Jalkotzy
1992
Spreadbury et al.
1996
Logan and Sweanor
2001
Logan and Sweanor
2001
Cooley et al. 2009

655

2.5

4.8

3.6

Cooley et al. 2009

30%

2.2

3.6

4.0

Robinson and
DeSimone 2011

43%

39%

2.2

4.5

3.5

57%

61%

1356 7

915
average: 37%
% independent lions:

63%

Table 1. Lion age/sex composition and population densities in multi-prey systems of the western U.S.

Page   3

 Habitat
quality

Area_km2

Assumed lion
density
(lions/100 km2)

Estimated
number of lions of
all age classes

High

4,150

4.5

187

Medium

4,631

3.5

162

Low

731

2.2

16

Non-habitat

871

0

0

L-6 total

10,383

365

Estimated number of
adult & subadult lions
(assuming 61% of total
population)

223

Table 2. Estimated lion population in DAU L-6.

Mortality type

8%

12%

15%

Total mortality (2011
recalculation)
Non-hunt mortality objective
Harvest Objective (2011
recalculation)

18

27

33

Average
annual
mortality
at 8-15%
range
26

3
15

3
24

3
30

3
23

Annual Mortality Rate

Average
annual
mortality
at 12-15%
range
30
3
27

Old harvest objective (200515
23
29
22
2010/11 seasons)
Table 3. Total mortality and harvest mortality at various annual mortality rates. The past harvest
objective was based upon 8-15% mortality, or 15-29 lions harvested (average 22 lions). The new harvest
objective calculation would be an average of 24 lions harvested (based on a 8-15% total mortality) or 28
lions harvested (based on a more liberal harvest of 12-15% total mortality)

Page   4

 Figure 1. Lion habitat quality in DAU L-6. High quality habitat is considered ato be areas within deer, elk,
and bighorn sheep winter range below 11,500 feet elevation. Medium quality habitat is areas outside of
big game winter range and below 11,500 feet. Low quality habitat is considered areas of urban
development and open rangeland below 11,500 feet. All areas above 11,500 feet are considered nonhabitat.

Page   5

  

 

 
  
 
 
 
 
 
 

ion DAU L-6 I
11 Recalculated lion densities

Lion habitat quality
H'gh qml'ty
Mac-um 
Low wait]
Non-habitat A
Rama

 

 

RIO BLANCO

 

 

9am: 

     

 

.nn_una

 

 

LB_GMU_Boundaties

 

 

CHAFFEE

 

 

Page 6