COUGAR PREDATION ON MOOSE IN SOUTHWESTERN ALBERTA

Prey selection, and kill and consumption rates by cougars (Puma concolor) were studied in the Sheep River area of southwestern Alberta during winter from 1981 to 1994. We investigated 368 kills made by cougars. All 5 ungulate species available within this study area were taken by cougars. Ungulates provided >99% of the biomass consumed by both male and female cougars between November and April each year. Female cougars killed mostly mule deer (Odocoileus hemonius) and elk (Cervus elaphus), but all males we studied specialized in moose (Alces alces). Of 54 moose fed upon by cougars, 4 were adults which had been found dead and scavenged. Forty-four calves (7-12 months) and 6 yearlings (13-20 months) were killed by cougars: 14 by females, 34 by males, and 2 by cougars of unknown sex. Moose comprised an estimated 12 % of the biomass consumed in winter by female cougars, and 92 % of that for males. A model derived from observed kill rates and the estimated cougar-population structure predicted that Cougars in the 515 km2 study area would kill 18 moose calves and 3 yearlings each winter between December and March. This study represented 16-30 % of the estimated early winter calf crop