Winter diet and hunting success of Canada lynx in Colorado

Abstract

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. Ó

Understanding and predicting habitat for wildlife conservation: the case of Canada lynx at the range periphery

“…This pattern was expected and consistent with Canada lynx specializing on snowshoe hares (Elton and Nicholson , Krebs et al. , Ivan and Shenk ). Finally, male lynx demonstrated a positive functional response (increasing use with increasing availability) for advanced regeneration while females demonstrated additive use (Fig.…”

“…), but the mature structure class is where hares are most accessible for lynx (Fuller et al. , Ivan and Shenk ). This mechanism received demographic support by Kosterman (), who demonstrated that female lynx with core areas of highly connected mature forest and intermediate levels of regenerating forests had the highest probability of producing a litter.…”

Winter recreation and Canada lynx: reducing conflict through niche partitioning

“…That is, adding recreational activities to our models may have, in some sense, been a proxy for adding stem density and horizontal cover, which is a primary factor affecting lynx resource use across the species’ southern periphery (Squires et al. , McCann and Moen , Ivan and Shenk , Holbrook et al. ).…”

“…, Thornton et al. , Ivan and Shenk ) that is less likely to exclude backcountry skiers compared with motorized recreationists traveling at high speeds (Olson et al. ).…”

Forest structure provides the income for reproductive success in a southern population of Canada lynx

“…, Holbrook et al. ) and lynx are more successful at killing snowshoe hares in mature forest than regenerating forest (Ivan and Shenk ). In addition, lynx exhibit strong selection for mature forest and use this structural stage twice as much as any other during both winter and summer seasons (Holbrook et al.…”