Effect of sociality and seadon on gray wolf

Effect of Sociality and Season on Gray Wolf (Canis lupus)
Foraging Behavior: Implications for Estimating Summer
Kill Rate
Matthew C. Metz1,2*, John A. Vucetich1, Douglas W. Smith2, Daniel R. Stahler2, Rolf O. Peterson1
1 School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan, United States of America, 2 Yellowstone Wolf Project,
Yellowstone Center for Resources, Yellowstone National Park, Wyoming, United States of America

Abstract
Background: Understanding how kill rates vary among seasons is required to understand predation by vertebrate species living in temperate climates. Unfortunately, kill rates are only rarely estimated during summer.
Methodology/Principal Findings: For several wolf packs in Yellowstone National Park, we used pairs of collared wolves living in the same pack and the double-count method to estimate the probability of attendance (PA) for an individual wolf at a carcass. PA quantifies an important aspect of social foraging behavior (i.e., the cohesiveness of foraging). We used PA to estimate summer kill rates for packs containing GPS-collared wolves between 2004 and 2009. Estimated rates of daily prey acquisition (edible biomass per wolf) decreased from 8.460.9 kg (mean 6 SE) in May to 4.160.4 kg in July. Failure to account for PA would have resulted in underestimating kill rate by 32%. PA was 0.7260.05 for large ungulate prey and
0.4660.04 for small ungulate prey. To assess seasonal differences in social foraging behavior, we also evaluated PA during winter for VHF-collared wolves between 1997 and 2009. During winter, PA was 0.9560.01. PA was not influenced by prey size but was influenced by wolf age and pack size.
Conclusions/Significance: Our results demonstrate that seasonal patterns in the foraging behavior of social carnivores have important implications for understanding their social behavior and estimating kill rates. Synthesizing our findings with
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