Proceedings of the Seventh Mountain Lion Workshop

FOUR DECADES OF COUGAR-UNGULATE RELATIONSHIPS IN THE CENTRAL
IDAHO WILDERNESS
HOLLY A. AKENSON, University of Idaho, Taylor Ranch Field Station, HC 83 Box 8070,
Cascade, ID 83611, USA, e-mail: tayranch@direcpc.com
JAMES J. AKENSON, University of Idaho, Taylor Ranch Field Station, HC 83 Box 8070,
Cascade, ID 83611, USA; e-mail: tayranch@direcpc.com
HOWARD B. QUIGLEY, Beringia South, 2023 Stadium Drive, Suite 1A, Bozeman, MT
59715, USA
MAURICE G. HORNOCKER, Wildlife Conservation Society, 2023 Stadium Drive, Suite 1A,
Bozeman, MT 59715, USA
Abstract: Research conducted on cougars (Puma concolor) in the Big Creek drainage in each of
the last four decades has enhanced the understanding of the dynamic nature of cougar – ungulate
relationships. In 1964, Maurice Hornocker initiated his benchmark research on this cougar
population and assessed the role of cougar predation in regulating ungulate populations. Each
study that followed has had different objectives, yet, combined these projects provide a rare
continuum of ecological information on the dynamics of cougar – prey relationships. This
cougar population has been influenced by significant environmental changes over the last 40
years. The ungulate prey base has fluctuated, but generally elk numbers have increased and deer
have decreased. Total ungulate biomass was similar in the 1960’s and 1980’s, but was 12%
lower in the study just completed. The dynamics of carnivore competition, both inter-specific
and intra-specific, has changed since introduced wolves recolonized the drainage in the 1990s. A
large-scale forest fire 2 years ago drastically altered winter and summer ranges and affected
predator – prey relationships. We compared cougar population size, structure, reproduction, and
mortality factors; prey selection during 3 time periods; and evaluated pre and post-fire data in the
recent study. The estimated resident cougar population was 9 adults during the first 2 studies in
the 1960’s and early 1970’s. The resident population grew to an estimated 13 adults in the mid-
1980’s, but dropped to 10 individuals by 2000, and down to 6 resident cougars by 2002. The
population increase during the 1980’s was in the adult female segment and it corresponded with
an increasing elk population. The current low population is a result of a decreasing elk
population, ungulate displacement from fire, increased hunter harvest of cougars, increased
intraspecific strife, and competition with wolves for the same prey base. Cougars selected for
elk rather than mule deer during the first study, but killed elk in proportion to their relative
abundance during the study in the 1980’s and recent study (2000). Historical perspectives from
pioneer diaries indicate similar cougar population numbers. In 1888 a bounty hunter removed 12
cougars from the drainage, then ten years later a different cougar hunter noted trapping and
poisoning 12 individuals on Big Creek. Archeological evidence, old newspaper articles and
diaries, and early agency field notes are all integrated into this discussion of long-term predator -
prey relationships. The lengthy record of information on predator and prey populations in the
Big Creek drainage arguably makes this cougar population the best understood in North
America.
PROCEEDINGS OF THE SEVENTH MOUNTAIN LION WORKSHOP
127