Yellowstone Elk decline continues

The northern elk herd in Yellowstone National Park went into 2004 at its smallest size since 1988, primarily due to drought, wolves, severe past winters and outside hunting, officials said.

An aerial survey last December found 8,335 elk in and around the park. In December 2002, researchers counted 9,215 elk.

The highest December count ever calculated was in 1994, when 19,045 elk were found in good spotting conditions, said P.J. White, a wildlife biologist in Yellowstone.

The size of the herd has come under intense scrutiny since wolves were reintroduced to the park in 1995 and 1996. Elk numbers have been dropping steadily since then.

White said wolf kills are one of the primary factors contributing to the herd’s decline since the mid-1990s.

However, in recent years, wolves have not been the most lethal elk predators.

Recently releases study results have shown than grizzly and black bears killed a majority of elk calves in the north side of the park for the second year in a row.

Researchers monitored 44 calves this spring and summer in the second year of a three-year study to determine what is killing calves in the park’s northern range.

Of the 44 calves monitored this year, 31 died. Of those, 18 were killed by grizzly and black bears, four by coyotes, three by wolves and one by a golden eagle, researchers said.

One calf was killed by wolves or bears, two were killed by unknown predators and two died for reasons other than predators.

In the study’s first year in 2003, bears killed 19 elk calves, wolves killed five, coyotes killed three, a mountain lion killed one and a wolverine killed one. Two were killed by wolves or bears.

Researchers warned against reading too much into the research, and said another year of data must still be collected.

“These cause-specific mortality results are preliminary and could easily be misinterpreted,” said the report written by researchers from the Yellowstone Center for Resources, the U.S. Geological Survey and the University of Minnesota.

Although bears were responsible for 58 percent of the calves’ deaths between May and September, wolves could play a larger role at other times of the year, the researchers said.

Bears tend to hunt in a grid-like pattern in the spring and summer in search of young calves that are hiding, while wolves are more likely to kill calves in the fall and winter when they’re with larger groups of elk, according to the study. The number of elk killed by bears could also be affected by changes in other food supplies.

Other factors for the elk decline include five years of drought, big winter kills in 1996-97, and the shooting of thousands of animals during annual late hunts in Gardiner, Mont.

The hunts, designed to kill migrating elk before they damage winter range outside the park, have been cut back “as total elk numbers and elk migrations outside of the park have declined in recent years,” said Tom Lemke, a biologist for the Montana Department of Fish, Wildlife and Parks.

About 1,400 permits were issued last year, down from 2,880 in previous years. Harvest figures have also fallen from 2,365 elk in 1997 to just 718 elk killed last year, Lemke said.