Yellowstone Wolf Project: Annual Report 2011

Smith, D; Stahler, D; Stahler, E; McIntyre, R; Metz, M; Irving, J; Raymond, R; Anton, C; Kindermann, R; Bowersock, N

At the end of 2011, at least 98 wolves in 10 packs and including 2 loners occupied Yellowstone National Park (YNP). The number of breeding pairs (8) was the same as in 2010, when the population size was 97. However, the northern range wolf population has declined approximately 60% since 2007, mostly because of a smaller elk population, the main food of northern range wolves. The interior wolf population has declined less, probably because they augment their diet with bison. The severity of mange continued to decline in 2011, although some packs still showed signs of the mite. There was no evidence that distemper was a mortality factor as it was in 1999, 2005 and 2008. Pack size ranged from 3 (Agate Creek) to 19 (Mollie’s) and averaged 10.2; the long-term average is 10. All nine packs that we had information on had pups. (We could not assess the reproductive status of the Bechler pack.) The average number of pups in early winter for packs that had pups was 4.1, compared to 4.8 in 2010 and 3.8 in 2009. A total of 34 pups in YNP survived to year end, four less than in 2010. Project staff detected 343 kills (definite, probable, and possible combined) made by wolves in 2011, including 267 elk (78%), 15 bison (4%), 18 deer (5%), 1 moose (<1%), 2 pronghorn (<1%), 2 bighorn sheep (<1%), 2 badgers (<1%), 1 jackrabbit (<1%), 14 coyotes (4%), 1 raven (<1%), 7 wolves (2%), and 13 unknown prey (4%). The composition of elk kills was 27% calves, 3% yearlings, 44% cows, 18% bulls, 3% adults of unknown sex, and 6% of unknown sex and age. Bison kills included 5 calves, 1 yearling, 2 cows, 6 bulls, and 1 adult of unknown sex. Other research topics included population genetics, population regulation, disease, hunting behavior, spatial analyses of territory use, wolf pack leadership, multi-carnivore-scavenger interactions, breeding behavior, dispersal, and observations of wolf, grizzly bear, and bison interactions in Pelican Valley. In 2011, twelve wolves from six packs were captured and collared. At year end 17% of the wolf population was collared. Wolf management activities included den site closures, several hazing events, and one removal of a food-conditioned wolf. Staff continued to manage wolf viewing areas in Slough Creek and Lamar Valley and other places where wolves were frequently sighted. Wolf Project staff made 17,635 visitor contacts during 2011 and estimated that 25,000 people observed wolves in the park. Wolf Project public outreach included 241 talks and 84 interviews. Additional information on wolves in Yellowstone National Park and previous annual reports are available at www.nps.gov/yell/naturescience/wolves.htm, www.greateryellowstonescience.org, and www.westerngraywolf.fws.gov.

Yellowstone Wolf Project: Annual Report 2011

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