Current Projects

Effects of Hunting on Cougar Population Ecology

Hilary Cooley, H.S. Robinson, B.T. Maletzke, G.M. Koehler, R.B. Wielgus & others

This project is on-going as part of Hilary Cooley’s, Hugh Robinson’s,and Ben Maletzke’s Ph.D. programs. We compared a heavily-hunted (Kettle Falls WA) and a very lightly hunted population (Cle Elum WA) to test for differences in population demography. We examined male mortality, male immigration, female maternity, cub survival, female survival, and population growth rates to test the “closed population, increased reproduction” or “open population, decreased reproduction” hypotheses of population regulation in large carnivore populations. (See hunting of grizzlies in Completed Projects). High mortality of resident adult males resulted in increasing numbers of potentially infanticidal immigrant males, decreasing numbers of juveniles and females, but no net change in total cougar numbers. Low mortality resulted in high emigration of younger animals, stable numbers of juveniles, females, and males, and no net change in total cougar numbers. Hunting did not reduce total numbers or densities of cougars, as commonly thought, because of male immigration. Lack of hunting did not increase total numbers or densities of cougars, as commonly thought, because of emigration. Hunting caused a shift in the sex and age structure towards younger males and a female population decline. Our results support the open population, decreased reproduction hypothesis of cougar population regulation.

Robinson, H.S., R.B. Wielgus, H.S. Cooley, and S.W. Cooley. 2008. Sink populations in large carnivore management: cougar demography and immigration in a hunted population. Ecological Applications (In Press). See Sink.pdf

Cooley, H.S., R.B. Wielgus, G.M, Koehler, and B.T., Maletzke. 2008. Source populations in large carnivore management: cougar demography and emigration in an unhunted population. Ecological Applications (In Prep).

Effects of Hunting on Cougar/Human Conflicts

Ben Maletzke, G.M. Koehler, H.S. Cooley, & R.B. Wielgus

This project is on-going as part of Ben Maletzke’s Ph.D. program. Heavily hunted and white-tailed deer occupied areas appear to show much greater incidences of cougar-human conflicts (cougar complaints, cougar use of human occupied areas; attacks on humans, pets, and livestock) than lightly hunted, white-tail free areas. We hypothesize that heavy hunting of resident adult cougars in such areas results in high rates of immigration and settling by sub-adult males and that these males use human-occupied and white-tailed deer areas, and cause more attacks than adults. Results to-date indicate that unhunted, older, resident cougars have stable home ranges and avoid human-occupied areas whereas hunted, younger, immigrant cougars have unstable home ranges and use human-occupied areas. Heavy hunting and white-tailed deer expansion appears to exacerbate, not alleviate, cougar/human conflicts.

Effects of Hunting on Cougar Prey Selection and Sexual Habitat Segregation

Jon Keehner, H.S. Cooley, and R.B. Wielgus

This project is on-going as part of Jon Keehner’s M.S. to Ph.D. Program. Cougars selectively prey on mule deer but not sympatric white-tailed deer. We tested and rejected the hypothesis that many mule deer killed by cougars are actually mule deer/white-tailed deer hybrids that have poor predator avoidance and escape strategies. We also tested and supported the hypothesis that selection for mule deer was caused by cougar sexual habitat segregation. Only females (especially those with kittens) select for mule deer. Our preliminary results suggest that high mortality of resident adult males and corresponding high immigration by potentially infanticidal males results in sexually selected habitat segregation. Females with vulnerable offspring appear to select for high elevation, low density, mule deer ranges where infanticidal immigrant males are rare. Males select for low elevation, high density white-tailed deer ranges. Hunting of cougars may actually exacerbate, not alleviate, high predation on declining mule deer.

Effects of Sex and Age on Cougar Prey Selection in a Mule Deer and Elk Community

Kevin White, B.T. Maletzke, G.M. Koehler, & R.B. Wielgus

This project is on-going as part of Kevin White’s M.S. program. We are examining cougar prey use and selection in a sympatric mule deer and elk community in Cle Elum WA. Our preliminary results suggest that large male cougars may kill elk more frequently than females. The “habitat or prey switching hypothesis” predicts that large males select for elk as primary prey by hunting and killing in different habitats (e.g., higher elevations). The “incidental kill hypothesis” predicts that large males kill elk as secondary prey in the same areas as others but are more successful on elk because of their larger size. Our results could have important implications for understanding and managing predator/prey communities.

Population Growth and Persistence of Endangered Mountain Caribou in the Selkirk Mountains

Jon Almack, W. Wakkinen, & R.B. Wielgus

This project is on-going as part of a collaborative effort by WSU, WDFW, IDFG, USFS, and USFW.We determined rates and causes of mortality, reproduction, and population growth for the last remaining mountain caribou population in the lower US. Results indicated that this population was decreasing because of high predation by cougars due to expanding white-tailed deer. First year survival of transplant caribou was much lower than in subsequent years. This appears to be due to capture and handling stress, not naive prey hypothesis. Demographic analysis suggests the population is currently stable after cougar reductions and Population Viability Analyses (PVA) suggests the population can recover with additional transplants.