Survival And Mortality Of Mountain Lions In The Blackfoot Watershed, West-Central Montana

Scientific Disciplines
Biological Sciences - Terrestrial
University of Montana
mountain lion
puma color
montana cooperative wildlife research
Volume 17, No. 1-4

Survival and mortality of mountain lions in the blackfoot 
Watershed, west-central montana
Hugh Robinson,* Montana Cooperative Wildlife Research Unit.  University of Montana, Missoula, 
Montana 59812
 Richard DeSimone, Montana Fish, Wildlife and Parks (Retired).  Helena, Montana 59620
We investigated population effects of harvest on mountain lions (Puma concolor) using 
a pseudo-experimental before-after-control-impact (BACI) design. We achieved this through 
3 yrs of intensive harvest followed by a recovery period. In December 2000, after 3 yrs of 
hunting, approximately two-thirds of district 292 was closed to lion hunting, which effectively 
created a refuge, representing approximately 12 percent (915 km2) of the total Blackfoot 
watershed (7908 km2). Hunting continued in the remainder of the drainage, but harvest levels 
declined between 2001 and 2006 as quotas were reduced. From January 1998 and December 
2006, a total of 121 individual mountain lions were captured, 152 times, including 82 kittens, 
and 39 juveniles and adults. Of these, 117 individuals were collared and monitored on average 
for 502 days (~ 16 mos) with males remaining on the air for shorter periods (  =284 days) 
than females (  =658 days). Hunting was the main cause of mortality for all age and sex 
classes across the study period, accounting for 36 of 63 mortalities documented. This was 
followed by illegal mortalities, natural, unknown, depredation, and vehicle collisions. Across 
the study period, any lion in the Blackfoot watershed had, on average, a 22 percent annual 
probability of dying due to hunting. We found human harvest to be an additive mortality 
source, i.e., hunting mortality was not compensated for by increased survival of remaining 
individuals that shapes the overall survival structure of mountain lion populations. As such, 
wildlife managers through the use of human harvest, have the capability to regulate mountain 
lion population growth.