Antelope numbers up, in spite of a dry year
By Mike Koshmrl, Jackson Hole, Wyoming
September 13, 2012
A Wyoming Game and Fish Department count shows the pronghorn population in the Jackson-Pinedale area bounced back after a down year in 2011.
Ungulate biologists tallying animals by horse and plane counted about 8,600 pronghorn, well above the 7,000 counted last year. Although a good increase on the year, that falls within the short-term average, said Scott Smith, Game and Fish’s Pinedale-area wildlife management coordinator.
“Looking at the five-year average — about 8,400 — that’s right in there,” Smith said.
The survey, an assessment of the well-publicized Path of the Pronghorn migration, is used to determine hunting quotas and seasons for the following year. It’s a trend survey and is not considered a census count.
The fawn ratio in the herd, 72 per 100 does, was considerably higher than last year, when it was 64 fawns per 100 does. The five-year average is 61 fawns per 100 does.
“That’s a fairly notable jump, particularly with the drought we’re having,” Smith said.
Combined with how harsh winter is, fawn ratios are a major determinant of the following year’s population growth.
The herd’s reproductive success and distribution varied greatly between wet and dry areas, Smith said. Agricultural and irrigated lands were consistently returning counts of 80 fawns per 100 does, but on arid Bureau of Land Management lands the numbers were in the low 60s, he said.
The Jackson Hole segment of the herd turned in near-record numbers this year, with 400 animals tallied in the Gros Ventre drainage and Grand Teton National Park.
“It’s good news for the antelope here,” Game and Fish wildlife biologist Doug Brimeyer said in an August interview.
Brimeyer counted the highest local fawn ratio, 80 fawns per 100 does, since modern record-keeping started in 1985.
Regionally, Smith said, the counts bode well for pronghorn.
“Going into this hunting season, antelope abundance will be good,” he said. “Buck numbers are good, and with that kind of fawn production the carryover to future years should be good, provided they get through the winter.”