Wyoming wolf count: At least 230
by Cat Urbigkit, Pinedale Online!
March 12, 2012
The U.S. Fish and Wildlife Service annual wolf monitoring report has been released, and here’s a summary of information about Wyoming’s wolf population.
"WY (outside YNP): Hereafter Wyoming (outside YNP) will be referred to as WY. From 2009 through 2011, the 3-year mean wolf population size in WY was 233 (SD = 11.4; range = 224- 246).
"In 2011, the WY wolf population was >230 wolves in >38 packs including >19 breeding pairs which represented a slight decline in the total number of wolves from 2010 (246); however, the population remained at the 3-year average. At least 15 lone wolves were identified and located throughout the western portion of the state. Average pack size was 6.1 wolves per pack and average litter size was 3.6 pups per litter as of 31 December 2011. We documented 51 mortalities (18% of the population). Causes of mortality included: agency control = 36; under investigation or unknown = 6; human caused = 6; and natural = 3.
"We managed wolf population growth and wolf distribution to minimize chronic loss of livestock from wolves and promote wolf conservation by maintaining the WY wolf population well above recovery objectives. We recorded 65 livestock (35 cattle and 30 sheep), 1 dog, and 1 horse as confirmed wolf-kills. Fourteen packs (37% of WY packs in 2011) were involved in >1 depredation; 6 packs (16%) were involved in >2 depredations; and 5 packs (13%) were involved in >3 depredations in 2011. Agency control efforts removed 36 depredating wolves (13% of the population) to reduce livestock losses due to wolves. The State of Wyoming paid $123,703.00 to compensate cattle producers and wool growers who lost livestock to wolves in 2011.
"YNP: At the end of 2011, at least 98 wolves in 10 packs (8 breeding pairs), with 2 loners, occupied Yellowstone National Park (YNP). This is the same population size as 2010 (97 wolves) and represents possible population stabilization within YNP. Breeding pairs were also stable at eight. 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, which has resulted in increased intraspecific competition for fewer resources. 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 of distemper being 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, equal to the long-term average (10). Nine of 9 (100%) packs that we had information on had pups (the reproductive status of the Bechler pack was unknown). The average number of pups/pack in early winter for packs that had pups was 4.1, slightly lower than the 2010 average of 4.8 pups/pack, but higher than 2009 (3.8). A total of 34 pups survived to year end in YNP, four less than in 2010.
"During the wolf-prey relationship study, 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 unknown sex adult.
"Other research 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.
"Wolf management activities included den site closures, several hazing events, and one removal of a food conditioned wolf. Twelve wolves were captured and collared in 6 packs. At year’s end 17% of the wolf population was collared. Staff continued to manage wolf viewing areas in Slough Creek and Lamar Valley and other hot spots where wolves were frequently sighted leading to 25,000 people observing wolves and 17,635 visitor contacts by Wolf Project staff. Wolf Project public outreach included 241 talks and 84 interviews."¯
To read the complete annual report, click on the link below.