Yellowstone Wolf Project: Annual Report 2002

Smith, Douglas; Stahler, Daniel; Guernsey, Debra

At the end of 2002, at least 272 wolves in 31 packs were present in the greater Yellowstone area (GYA), representing 22 breeding pairs. Overall 43 breeding pairs were present in the three recovery areas of greater Yellowstone, central Idaho, and northwest Montana. This was the third year when at least 30 breeding pairs were present in the northern Rocky Mountains, the minimum population size for delisting from the endangered species list. With the biological criteria met for delisting, the states of Idaho, Montana, and Wyoming need to complete approved management plans to ensure adequate wolf populations in the future. When state plans are approved, the U.S. Fish and Wildlife Service will delist wolves. As of this writing, state plans were not approved. Pack size in Yellowstone National Park (YNP) ranged from 2 to 20 wolves and averaged 10.6. As expected, the Druid Peak pack did not maintain its record high pack size and at yearʼs end consisted of only 11 wolves, down from a high of 37. Wolves dispersing from this pack were responsible for the formation of three new packs: Buffalo Fork, Geode Creek, and Agate Creek. The smallest pack, the Tower pack, remained only a pair of wolves probably because they were attacked by the Agate Creek wolves while the female was pregnant. One other new pack of four wolves formed in the Bechler region, the first recorded activity of a pack there since wolf reintroduction. At least 56 pups survived to the end of the year in YNP. Average pups/litter at yearʼs end was 4.3. Twelve breeding pairs produced 14 litters. The Druid Peak and Agate Creek packs each had two litters, but only 3 and 4 pups, respectively, survived from these litters. The Swan Lake pack may have had more than one litter, but genetic testing will be necessary to confirm. Five radio-collared wolves in YNP died in 2002. One was hit by a vehicle and the others died of natural causes. Eighteen wolves were captured by helicopter darting in February. Seven wolves were captured in late 2001, but were still part of the 2001–2002 season. All together 7 adults (28%), 8 yearlings (32%), and 10 pups (40%) from 9 different packs were captured and collared. Of those captured and collared, 18 were males (72%) and 7 were females (28%). Wolves were captured from the following packs: Druid Peak (7), Yellowstone Delta (5), Cougar Creek (3), Leopold (2), Rose Creek II (2), Sheep Mountain (2; captured by Wildlife Services), Mollieʼs (2), Nez Perce (1), and Chief Joseph (1). In addition to attachment of radio collars, standard measurements and blood (genetics and disease monitoring) were collected on all wolves handled. Weights of wolves, especially on the northern range, appear to be declining since systematic capture efforts were initiated in 1998. There were 35 (24%) wolves collared in YNP at the end of 2001.

Yellowstone Wolf Project: Annual Report 2002

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