Drought Hard on Pronghorn Antelope Herd

Fewer fawns of pronghorn antelope are surviving this year throughout Arizona, and the state’s prolonged drought may be the main factor.

However, wildlife experts insist that the species is not in danger of disappearing from the grasslands of Arizona.

“We’re nowhere close to saying they’re endangered or close to going extinct,” said Eric Gardner, a Prescott-based field supervisor for the state Game and Fish Department. “But we are seeing some declines in their population.”

The most recent surveys show that there are about 8,000 pronghorns statewide, with about 2,000 of them in central Yavapai County.

The antelope -- known for keen eyesight and running speed in excess of 60 mph -- breed in August and September, with their offspring usually born between late May and mid-June.

“Most do have twins. For every 100 does, we would expect 175 fawns. That’s quite a lot of babies,” Gardner said. “In a normal year, we’d like to see at least 30 of those fawns survive. This year, we’re seeing ratios of 4 or 5 per 100” in areas around Prescott, Prescott Valley and Chino Valley.

That’s not enough to replace the adult mortality because wild antelope usually only live six to eight years, according to experts.

Some other pronghorn habitats also are hurting as Arizona copes with its fourth year of drought.

“The bottom line is rainfall influences the growth of forage and the quality of forage,” said Brian Wakeling, big game supervisor for the Game and Fish Department. “The quality of milk the doe produces for feeding her young is influenced by her diet. The lactating phase takes a lot more energy than carrying the fetus. The drought influences all of those factors.”

Gardner said drought conditions also amplify other problems for the pronghorn -- predatory attacks from coyotes, loss of habitat and lack of ground cover for hiding.

Game and Fish crews calculate the pronghorn populations by doing aerial surveys every June. This year’s figures may not be finalized until fall because the recent wildfire that scorched nearly 470,000 acres in eastern Arizona probably will delay surveys there.

Gardner said the low survivor ratio in Yavapai County is offset by last year’s population boom, with a 70-fawn-per-100-doe ratio.

“That goes a long way to counteracting this year’s numbers,” he said. “The antelopes can quickly make up the loss in later years by retaining more twins. And the drought situation readies us to do some more management.”

Among the options is limiting hunting permits for the pronghorn, altering fence lines so that the animals can move more freely for food and forage, reverting juniper tree areas back to grasslands, and transplanting some antelope to other locations.