Boom, Boom on the Range

Where endangered Sonoran pronghorn antelope play under the roar of U.S. Air Force jets on live-fire bombing exercises

All in all, Hervert says, "If I was calling the shots, there would definitely be more active management of Sonoran pronghorn in spite of wilderness designations. We would be looking at reducing those factors that have a negative impact on Sonoran pronghorn."

Decrypted, that comment could spell more confusion and controversy among the web of agencies and interest groups transfixed on this small antelope.

Asked to elaborate on his preferred plan for saving the Sonoran pronghorn, John Hervert lists development of water sources, predator control and more capturing, collaring and radio monitoring of the animals--all actions certain to make some environmentalists gag on their trail mix.

Organizations such as Friends of Cabeza and the Wilderness Society can be counted on to oppose killing predators and creating water supplies for the Sonoran pronghorn. Hervert acknowledges that both measures are controversial.

In his 17-year career as an Arizona Department of Game and Fish biologist, Hervert has never advocated such extreme measures as predator control. Now he'd like to set up on the edge of pronghorn habitat, use varmint calls to lure coyotes, which are responsible for most pronghorn predation, then shoot them. He's writing an environmental assessment that would allow Fish and Wildlife managers to institute predator control on Cabeza Prieta during periods of winter drought. The public would be allowed to comment.

Pam Eaton, regional director of the Wilderness Society, says she finds it "interesting" that predator control is being considered. "I don't think there's a lot known about the distribution of predators in the range," she says.

Desert purists oppose water-source development because much of the pronghorn habitat is designated as wilderness and is not to be disturbed by man. The refrain about Sonoran pronghorn not needing freestanding water will be heard.

But many government biologists, including Luke's, also have reservations about artificial water sources. Bruce Eilerts calls them "fast-food stands for predators."

Eaton says the Wilderness Society opposed one proposal to create a water source for pronghorn because it would have been too intrusive, could have affected other species and was not scientifically sound.

"We've said we don't object to the idea per se, but we objected to this particular project as it was conceived," Eaton says.

There are manmade water sources sprinkled across the habitat, originally put there for cattle, but there's little reliable data on their usage by pronghorn--possibly because they are staked out by predators, or perhaps because the antelope are not in those areas during the driest months.

Another aerial count of pronghorn is set for next month, and if there are enough pronghorn to warrant more captures, Hervert wants to do that. However, he says he's been told that one conservation group may go to court to stop it.

Captures, in which individual antelope are caught in nets shot from helicopters, are indeed traumatic for the pronghorn. While in captivity, the animals are fitted with radio collars, and vital measurements and bacterial swabs are obtained. The chase and capture seldom last longer than 10 minutes--each minute crucial to an animal so frail that they have been known to succumb to capture stress.

Hervert concedes that a capture operation in 1994 was "disastrous"--due in part, he believes, to extreme drought stress the animals were enduring. Up to that point, he says, 160 Sonoran pronghorn had been captured in Arizona, and only one had died from capture stress.

But following the 1994 capture, six of 22 pronghorn collared were dead within two months. The radio collars have a mortality signal that begins pulsing once an antelope's pulse stops. Such a signal allows Hervert to find what's left of the pronghorn and try to figure out what happened.

Of those six mortalities, he attributes three directly to capture stress. Two others were killed by coyotes and one by a mountain lion.

Hervert participated in a subsequent capture in Sonora in which the pronghorn were given oxygen and intravenous fluids while they were studied. Those measures allowed biologists and veterinarians to hold the animals for up to 20 minutes and conduct more extensive tests. Yet the animals fared well, he says, and he hopes to use the same procedures--along with a five-minute chase limit--for any future captures in Arizona.

Since the 1994 captures, 11 of the 22 collared antelope have died from causes other than capture stress. Hervert fears that the entire population has declined at a quicker rate.

Estimates of fawn "recruitment" into the herd over the past 30 years have normally fluctuated between 30 and 50 fawns per 100 does.

During 1995, Hervert says, the ratio was 12 to 100.
This year, it's 0 to 100.
If conditions don't improve, wildlife managers may have to institute a captive breeding program.

One day last spring, John Hervert was observing a small group of pronghorn feeding on cholla. As the herd drifted off, he was startled by a pitiful sight: A day-old fawn staggered out of the thicket.

"It had the misfortune of being born in a cholla forest," he says. "Its head was completely covered with cholla. Its ears were stuck together on top of its head."

He watched as a doe spurned the fawn's efforts to nurse.
"I went down where this fawn had curled up--I had gloves on--and picked out all the needles I could."

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