Neonatal mortality of elk in areas with and without grizzly bears

Authors(s): B. Smith, E. Williams, F. Lindzey, R. Schiller and T. Moore

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Publication Date: 0000-00-00

Type: annual report

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Abstract: Objectives A study was designed and initiated in 1997 to document and compare causes of elk calf mortality in the grizzly-occupied East Study Area and a relativly grizzly-free area of GTNP west of the Snake River (West Study Area). The objectives were to: 1) Quantify cause-specific neonatal mortality of elk calves, and learn if predation by colonizing grizzly bears has reduced neonatal survival of elk calves in Jackson Hole since 1992. 2) Compare neonatal mortality of elk between the East and West Study Areas to assess effect of grizzly bear occurrence on elk calf survival. 3) If predation by grizzly bears is compensatory or additive to other causes of elk mortality. 4) Determine if grizzly bears may be preying on elk calves in the East Study Area and then switching to bovine calves after elk calves become too agile to be killed.;Several private, state, and federal cooperators funded this 3-year study. Findings and Status A total of 153 newborn elk were captured and radio-instrumented during the 3-year study. Eighteen of 68 calves died as neonates (birth through 31 July) in the East Study Area. Twenty-five of 85 calves died as neonates in the West Study Area. Predation by black bears, coyotes, grizzly bears, and mountain lions accounted for 32 of 43 mortalities of neonates. Six cases of grizzly predation occurred, 5 in the East Study Area. The 28 percent rate of neonatal mortality was significantly higher (P less than 0.05) than we documented during 1990-1992 (15 percent ). Concommitantly, recruitment of calves during winter was significantly lower during the late 1990s. One case of gray wolf predation on a radioed calf occurred in February 1999 -- the first year of recolonization of Jackson Hole by wolves dispersing from Yellowstone National Park. Field work is completed. A manuscript for submission to the Journal of Wildlife Management is in preparation.

Keywords: Teton County, Snake River, Jackson Hole, Grand Teton National Park, National Elk Refuge, animal, mammal, canine, 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