Consequences of the Extirpation of Predators on Moose

Abstract

This year was the first of our five year project. We established three primary study areas to examine possible biological effects of large predators on moose. Sites where fieldwork was conducted included apparent heavy predation by grizzly bears [the eastern slopes of the Talkeetna Mountains (Alaska)], little or no predation (Grand Teton National Park), and human predation (Bridger-Teton National Forest), the latter two in the southern portion of the Greater Yellowstone Ecosystem. Data were gathered in Alaska from April until August and, in Wyoming, for all months from February until August (except during April). At the southern Greater Yellowstone sites, information was collected on pregnancy rates, calf production, twinning, and juvenile and adult survivorship. Ecological and behavioral data gathered from all three sites included home range locations, foraging associations and rates, habitat use, group size, social interactions, migration, and responses to humans and potential predators. Twenty animals were radio-collared at the Wyoming site; as of December 1995 only 15 survived. One apparently starved to death, one was poached, one was legally shot, and two died of unknown causes. We improved our sample by using 13 females previously radio-collared on national forest lands by University of Wyoming and Wyoming Department of Game and Fish personnel. Of these, two died during the 1994-1995 winter and three had slipped their collars.