Home range characteristics of a subordinate predator: selection for refugia or hunt opportunity?

Abstract

AbstractCougars Puma concolor are described as ‘habitat generalists’, but little is known about which ecological factors drive their home range selection. For example, how do resource distributions and inter‐species competition with dominant competitors (i.e. wolves, Canis lupus) over such resources, influence the distributions of cougars on the landscape? We tracked cougars using Very High Frequency (VHF; 2001 to 2005) and Global Positioning System (GPS; 2006 to 2011) technology in the Southern Yellowstone Ecosystem (SYE) in northwestern Wyoming, USA. We tested whether data type (VHF vs. GPS), cougar sex, access to forests (refugia) or hunt opportunity explained the size of 50% and 95% kernel density estimator (KDE) home ranges. Second, we quantified attributes of cougar home ranges and tested whether they were different from attributes of the overall study area, to address the ecological question: Do cougars select home ranges based on the availability of refugia, hunt opportunity or some combination of the two? Cougar sex and data type proved significant predictors of home range size for both 95% and 50% KDEs, and the amount of forest partly explained the size of 50% KDEs. Cougar home ranges derived from VHF data were 1.4–1.9 times larger than home ranges derived from GPS data; however, home range attributes determined from VHF and GPS data were remarkably equivalent. Female cougars selected home ranges with higher hunt opportunity than males, supporting the assumption that females primarily select home ranges with suitable prey to sustain themselves and their young. All cougars selected home ranges further from known wolf packs, providing evidence for newly established competition between resident cougars and recolonizing wolves, but did not select home ranges with greater access to landscape refugia. Our results provided evidence that cougars in the SYE select home ranges that provide high hunting opportunity and a spatial buffer that mitigates potential conflicts with a dominant competitor.