Elk, Bison Populations in Yellowstone National Park Said To Be Stable

Yellowstone's elk and bison herds are relatively stable, population-wise, when compared to recent year's numbers, according to park officials. Photo of bison on the Northern Range by Kurt Repanshek

Late-winter surveys of elk and bison herds in Yellowstone National Park show the animals are maintaining relatively stable populations compared to recent years, according to park biologists.

Whereas the park's bison herds total about 3,000 animals, the elk population is pegged at just under 6,100 animals. The elk tally, though, is a far cry from the days when Yellowstone's elk numbers were pushing 20,000 during the winter and 30,000 in summer.

Both counts were made from aerial surveys. Poor conditions -- low snowpack that had a number of bare areas in the park -- led park officials to say the bison tally was probably an underestimate by as much as 10 percent.

Fifty-six percent of the bison are in the Northern Range herd, with 44 percent in the Central Interior herd, they said. Last year the survey estimated bison numbers at 2,900 animals.

Of particular note in light of the acrimony that has surfaced in recent years over the steps taken in Montana to keep bison from possibly transmitting brucellosis to livestock herds is that just four bison were taken by hunters this winter, and no other bison were captured or shipped to slaughter, park officials said.

As for the elk herds, biologists say the winter tally has remained "fairly stable since 2006." As with the bison count, the elk count was hampered by low snow conditions and poor flying conditions, the park said.

The herd winters between the park's Northeast Entrance and Dome Mountain and Dailey Lake in Paradise Valley, Montana. Half of the elk counted this year were inside Yellowstone, while the other half were observed north of the park boundary, park officials said.

This population count is down significantly from the 9,545 elk counted during the winter of 2004-2005.

The long-term trend shows a 60-percent decrease in elk numbers since wolves were restored in the region, the officials said. However, a significant reduction in both wolf numbers and wolf predation has been observed on the park’s northern range.

Biologists believe elk numbers have decreased in areas where there are higher numbers of wolves and grizzly bears, but have stabilized or even increased in areas where there are fewer predators and moderate population reduction due to hunting, the park said in a release. In addition, fewer elk calves survive in areas where there are more predators.