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

Harvest Rate Change
Four long-term cougar research projects were conducted in Unit 26 using capturerecapture
and radio-telemetry techniques to produce a resident cougar population
estimate for each time period. Hornocker (1970) and Seidensticker et al. (1973)
determined that the cougar population was stable with a stable-to-increasing elk and mule
deer prey base and minimal harvest (no harvest in the first period and mean annual
harvest of less than 1 cougar in the second period). Each study identified a resident
cougar population of 6 females and 3 males during 1965-1969 and 1970-1973 study
periods. Quigley et al. (1989) found that the resident cougar population had increased to
10 females and 3 males simultaneously with an increased prey base, primarily elk, and
light harvest (mean annual harvest of 1.0 cougars) during the 1984-1986 period.
Akenson et al. (2005) documented a declining resident cougar population that initially
consisted of 6 females and 4 males, which then decreased to 4 females and 2 males
during the 1999-2002 time period. This decline occurred concurrently with high cougar
harvest (mean annual harvest of 3.8 cougars), a declining elk prey base, new wolf use in
the unit, and a large-scale wildfire in 2000 that significantly altered the environment.
Cougar harvest in Unit 26 increased nearly 4-fold over the past 4 decades. This is in
contrast to the trend from resident cougar population estimates from 4 cougar research
projects conducted in Unit 26 during 1965-2002 (Fig. 3). The consequence of higher
harvest in Unit 26 without a similar change in the cougar population was an increase in
the harvest rate on cougars. The harvest ratio (harvest per resident adult population) for
each decade increased from 0.11 during 1960s and 1970s research to 0.17 during the
1980s, and 0.34 to 0.67 during the 1999-2002 research period, reflecting an increasing
harvest rate trend over time. During the 1998-2006 time period, we estimated 29-48% of
resident adult cougars and 21-32% of resident adult female cougars were harvested
annually in Unit 26.
14
12
10
8
6
4
2
0
1960s 1970s 1980s 1990s 2000s
Mean Annual Harvest
Resident Population
Figure 3. Unit 26 – Big Creek mean annual cougar harvest by decade (Idaho Department of Fish
and Game Big Game Management Records database) compared to resident cougar population
estimates from Big Creek research in 1965-1969 (Hornocker 1970), 1970-1973 (Seidensticker et
al. 1973), 1984-1986 (Quigley et al. 1989), and 1999-2002 (Akenson et al. 2005).
Proceedings of the Ninth Mountain Lion Workshop
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