Data from two years of field research shows bears, not wolves to be the main cause of elk calf predation on the northern range of Yellowstone Park.

The past ten years biologists have recorded a low elk calf survival rate, nearly 50%. Wolf critics have claimed that wolves were the main culprit, and that having wolves reintroduced into Yellowstone would wipe out the elk.

The study, “Multi-Trophic Level Ecology of Wolves, Elk, and Vegetation in Yellowstone National Park” will continue another 3 years. Data collected the first year showed that bears took more elk calves than wolves.

Biologists ear tagged 44 new born elk calves during the second, 2004 study period with radio transmitters. Thirty one of the original 44 are now dead. Eighteen of the calves were taken by bears (black and grizzly), 3 – wolves, 4 – coyotes, 1 – golden eagle, 1 – unknown specie, bear or wolf, 2 – unknown predator, and 2 – non-depredation causes (natural or other).

During the first years study of 2003, 51 new born elk calves were ear collared, of which 34 died. Nineteen calves were killed by grizzly and black bears, 5 – wolves, 3 – coyotes, 2 – either bears or wolves, 1 – mountain lion, 1 – wolverine, and 3 – unknown causes (natural or other).