March 2016 Excerpt from Wolf Conservation and Management 2015 Annual Report
The Oregon State University/ODFW wolf-cougar research project in northeastern Oregon continued in 2015. This project is primarily focused on understanding competitive interactions and prey selection between wolves and cougars in the Mt Emily WMU.
Since summer 2014, researchers have collected data by monitoring 11 radio-collared wolves from 4 packs and 18 collared cougars using the Mt Emily WMU. Researchers used GPS location cluster analysis to identify potential prey acquisition sites (these are normally areas where wolves either have killed or scavenged prey) and document prey species selection and acquisition rates. To date, project researchers have investigated 458 potential wolf prey acquisition sites during winter months and 105 prey items were identified at these sites. Elk remains were identified at approximately 63% of acquisition sites and mule deer at 21% of the sites. White-tailed deer and non-ungulate prey were identified at 16% of the sites. Of the elk remains where age of animal could be determined, 49% were adults, 45% were calves, and 6% were yearlings. Of the mule deer remains, 69% were adults, 25% were fawns, and 6% were yearlings. Prey remains were also located at 44 of 201 potential wolf prey acquisition sites during summer months with elk comprising 61% of the prey remains, mule deer 18%, and white-tailed deer and non-ungulate prey the remainder. The age of the elk prey identified during summer months were calves (78%), adults (15%), and yearlings (7%).
The most common wolf-cougar interaction documented is wolves at cougar caches (63%). Six cases of wolves scavenging kills from cougar have been documented. Other interactions include two cases where wolves chased cougars up trees, one case of collared wolves chasing a collared cougar off a fresh kill, and one case of wolves killing young cougar kittens.
These results are preliminary and data collection for the wolf-cougar research project will continue through summer 2017. The project will continue to; 1) collar additional wolves and cougars within the study area and investigate competitive interactions between the two species, and 2) conduct cluster analysis and investigate prey acquisition sites for wolves and cougar during both winter and summer seasons. Data analysis and the project are expected to be completed in 2018.
March 2014 Excerpt from Wolf Conservation and Management 2013 Annual Report
Recovery of wolf populations in Oregon raises questions regarding wolf impacts on elk and mule deer populations, livestock depredation, and interspecific competition between wolves and cougars. The OWP directs the department to conduct relevant research to understand the effects of wolf re-establishment and to inform conservation and management actions. The vested interest of two key constituents, hunters and conservationists, also compels the department to investigate the impact of wolves on elk and deer. Information gained from research in the Northern Rocky Mountains provides insight into potential effects of wolf re-establishment in Oregon. However, several factors set Oregon apart from other areas where wolves have been studied. For example, the nearly singular importance of cougar predation on northeastern Oregon elk populations has rarely been documented elsewhere. Furthermore, the role of alternative prey species, differing antlerless harvest levels, and relatively mild climate in northeast Oregon all may influence the relationship between wolves and ungulates.
In early 2013 the department identified research recommendations specific to wolf-ungulate and wolf-predator interactions which included; 1) wolf prey preferences across a variety of ungulate assemblages in northeast Oregon; 2) wolf competition with cougars; and 3) shifts in ungulate habitat utilization. Previous research on elk and cougar in northeastern Oregon will provide comparative data on elk and cougar in some areas. Wolf-cougar interactions may be important because cougar predation on juvenile elk has been identified as the primary limiting factor of recruitment in northeast Oregon. If wolf packs reduce cougar densities or cause cougars to shift distributions and habitat use, wolf predation may be compensatory with cougar predation on elk. Alternatively, if wolves do not affect cougar populations, then wolf predation will be an additive source of mortality for juvenile and adult elk.
In October, 2013 the department initiated a partnership with Oregon State University to provide a Ph. D. student to study wolf-cougar interactions, and wolf predation rates on northeastern Oregon ungulates. Specific objectives of this project are;
- Determine prey selection of wolves in multiple packs in Oregon where prey availability differs among packs.
- Determine effects of presence of wolf pack(s) on population dynamics and habitat use of cougar in the Mt. Emily Wildlife Management Unit.
- Evaluate factors which may influence elk and deer populations and their habitat utilization in a mixed carnivore system with wolves.
The project will be conducted over four years and will focus on capture/collaring wolves and cougars, estimating prey selection of wolves, and evaluating survival, prey selection, and distributions of cougars to presence of wolves. The project is expected to be completed in 2018.
February 2013 ODFW Wolf Literature Review and Research Recommendations (pdf)