Date of this Version
The Journal of Wildlife Management 80(6):1049–1058; 2016
Information regarding the diet of Canada lynx (Lynx canadensis) at the southernmost extent of its range is critical for managing the species under current and predicted climate conditions. Therefore, from 1999–2009, we investigated winter diet and hunting strategies of Canada lynx in Colorado, USA by tracking individuals in the snow to identify sites where lynx encountered and killed prey. Similar to other parts of lynx range, snowshoe hares (Lepus americanus) were the primary winter food in Colorado, especially when considering total biomass consumed. Red squirrels (Tamiasciurus hudsonicus) comprised the bulk of the remaining food items and were a substantial occurrence during several years, which is consistent with previous hypotheses regarding the diet of lynx in southerly populations. Lynx successfully captured snowshoe hares on 31% of attempts and red squirrels on 47% of attempts, similar to lynx in other regions. In contrast to other populations, the majority of chases of both prey species were initiated while actively hunting rather than by ambush and this behavior did not change through time. We found evidence for snowshoe hare refugia during winter; hunting success for hares peaked at sites with approximately 3,000 stems/ha, but was lower in more dense vegetation where hare densities were greater. Given this finding and the apparent importance of red squirrels as alternate prey, we suggest that management for lynx in the southern Rocky Mountains, USA, focus on maintenance of mature, uneven-aged Engelmann spruce (Picea engelmannii)-subalpine fir (Abies lasiocarpa) stands. Such stands naturally provide patches of dense and open habitats juxtaposed closely together that should simultaneously facilitate high hare densities (and refuge from predation) and accessibility to hares by lynx. Mature trees in such stands also provide abundant cone crops to sustain populations of red squirrels for use as alternate prey.