Neonatal Mortality of Elk in Areas With and Without Grizzly Bears

Authors(s): B. Smith

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Publication Date: 0000-00-00

Type: annual report

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Abstract: Objectives 1) To learn if predation by colonizing grizzly bears has reduced neonatal survival of elk calves in Jackson Hole since 1992. 2) To understand the role of the grizzly bear in population regulation of the Jackson elk herd relative to other sources of mortality. 3) To determine if grizzly bears may be preying on elk calves in eastern GTNP and adjacent areas of Bridger-Teton National Forest and then swithching to bovine calves after elk calves become to agile to be killed. Findings and Status In this first of 3 field seasons, we captured and radio eartagged 45 elk calves during 27 May--7 June, 1997. We captured 24 calves (13 males, 10 females) in the East Study Area (ESA) and 21 (10 males, 11 females) in the West Study Area (WSA). Ten of these died during June and 4 died in July. During a 30 May capture flight, one additional female calf was found freshly dead in the WSA. Because diagnostic tests revealed this calf was born alive, it was included in our capture sample, bringing the number of calves that died to 15 of 46 (33%) captured. Predation accounted for 10 of 15 (67%) mortalities. Two calves were killed by grizzly bears, one in southern Yellowstone National Park, and one in eastern GTNP. Two calves killed by bears may have been predisposed. Calf 333 was diagnosed with lymphadenitis and calf 338 with severe necrotizing glossitis. Because cause-specific mortality on neonatal elk can vary annually (Singer et al. 1997, Smith and Anderson 1996), we are seeking funding to continue this study in 1998 and 1999. During each of those years we intend to capture and radio tag approximately 25 elk calves in the ESA and 25 in the WSA.

Keywords: Teton County, Snake River, Jackson Hole, National Elk Refuge, Grand Teton National Park, animal, canine, mammal, ungulate, elk , wapiti, Cervus elaphus, Cervidae, bear, grizzly bear, black bear, Ursus americanus, Ursidae, Ursus arctos horribilis, Canidae, Canis, Canis latrans, coyote, wolf, Canis lupus, Felidae, feline, lion, mountain lion, cougar, Felis concolor, mortality, population, predation, livestock, bovine, radio collar, Yellowstone National Park