Greater Yellowstone Ecosystem Report
The Greater Yellowstone Ecosystem (GYE) may support the densest populations of elk in North America, and a diverse community of large carnivores that prey on elk. The Jackson elk herd has doubled in size since 1984 and currently exceeds its winter population objective of 11,000 elk by about 5,000 animals (Smith and Anderson 1998). In and adjacent to Grand Teton National Park (GTNP), mortality of neonatal Jackson elk averaged 15% annually during 1990-1992 (Smith and Anderson 1996). Predation by black bears and coyotes, when calves were less than 4 weeks of age, caused 68% of neonatal mortality. Calves killed by mountain lions were more than 4 months old. Except for hunting, predation was the largest source of mortality of radiocollared elk from birth through adulthood. Since 1992, grizzly bear activity on federal cattle grazing allotments in eastern GTNP and the adjacent Spread Creek drainage of the Bridger-Teton National Forest (the East Study Area or East SA) has markedly increased and cattle losses to bears have become common. Personnel of the Wyoming Game and Fish Department attributed 26 cattle losses (25 calves, 1 cow) in the East SA in 1993 to grizzly bear predation. The Wyoming Game and Fish Commission, which compensates cattle producers for losses due to grizzly predation, initiated a study in 1994 to quantify the proportion of cattle losses in the East SA due to grizzly predation. One grizzly bear that was documented killing cattle each year, was captured and euthanized in GTNP in 1996.
Smith, Bruce L.; McFarland, Katherine C.; Lindzey, Fred G.; and Williams, Elizabeth S.
"Neonatal Mortality of Elk in Areas With and Without Grizzly Bears,"
University of Wyoming National Park Service Research Center Annual Report: Vol. 22
, Article 13.
Available at: http://repository.uwyo.edu/uwnpsrc_reports/vol22/iss1/13