Proceedings of the Ninth Mountain Lion Workshop - Carnivore ...

Discussion
A population can lose its ability to function as a source population due to a decrease in
productivity and recruitment or an increase in mortality, such that substantially fewer
subadults are available to disperse to other areas. The original population size could
remain stable, even with the lack of dispersers, until additional mortality and lack of
recruitment caused the population to decline.
In the central Idaho wilderness, where cougar populations have been managed to supply
dispersing animals to surrounding areas, hunter harvest should be managed to be light
enough to allow for continued high productivity. The central Idaho wilderness (Warren
and Selway DAUs) has been considered an area with difficult access, so cougar hunting
seasons have been more liberal than other parts of the state (Rachael and Nadeau 2002).
Wilderness cougar hunting opportunities in Idaho were expanded in 2002 in response to
big game hunter concerns about potential combined effects of cougars and wolves on elk
populations (Rachael and Nadeau 2002). Cougar hunters responded by increased use of
wilderness airstrips located in big game and cougar wintering areas and of hunting
outfitter facilities and services within the wilderness. These factors contributed to the
recent increase in Unit 26 cougar harvest levels and the high adult cougar harvest rate.
Logan and Sweanor (2001) and Anderson and Lindzey (2005) experimentally
manipulated cougar populations to determine the effects of removal on populations.
Logan and Sweanor (2001) determined that when off-take through capturing and
translocating cougars exceeded 28 percent of the adult population, the cougar population
declined. Anderson and Lindzey (2005) reduced a cougar population through intensive
hunter harvest, a 43% harvest rate, and then allowed the population to recover during a
period of light hunter harvest, an 18% harvest rate. Ross and Jalkotzy (1992) determined
that a cougar harvest rate of 11% did not prevent the population from growing. In
comparison, for Idaho’s Unit 26, the 1998-2006 estimated mean annual harvest rate of
29-48% of resident adult cougars strongly suggests that continuing to assume the
wilderness populations function as sources should be questioned and harvest rates revisited
for certain units. It should not be assumed that wilderness habitats, or any
habitats, always function as a source or a sink population.
Resident adult females, the breeding component of a cougar population, are the most
important age-sex class for directly influencing population productivity and growth
(Lambert et al. 2006). Adult female cougars invest extensive time in maternal care and
40 to 88% of resident females produce new litters each year (Logan 1983, Logan and
Sweanor 2001, Ruth et al. 2003) An average of 72% (range = 40 to 100%) of resident
females support dependent offspring