Steep Drop in Bighorn Sheep Tally : Wildlife: Helicopter survey finds only 60 in the San Gabriels, far fewer than the 222 in 1992. But experts say the decline may just be a result of inexact counting method.

State wildlife biologists find themselves with a disturbing version of Little Bo Peep’s problem: Where have all the sheep gone?

The latest helicopter survey turned up only 60 bighorn sheep in the San Gabriel Mountains north of Glendora, down from 222 in 1992. In the 1980s, aerial counts found as many as 500 of the reclusive animals.

So far, experts say, there is no obvious evidence of disease or major changes in habitat that would account for the decline. State officials, who have surveyed bighorn sheep numbers since 1976, “rarely find such dramatic differences,” said Steve Torres, a wildlife biologist for the state Department of Fish and Game.

Still, he said, biologists want to proceed cautiously.

“I’m not sure I’d call it a devastating decline,” said Torres, a bighorn sheep specialist. “We’re concerned about it, and the warning flags are up, and we need to do our homework.”

The San Gabriel bighorn sheep herd in the Angeles National Forest is the state’s largest. Statewide, biologists track 60 herds, a total of 4,600 bighorns. Bighorns, which are distantly related to domestic sheep, have huge, curly horns weighing up to 30 pounds. Their coat is not woolly but more the texture and color of deer fur.

Maybe, Torres said, the numbers are down because officials simply didn’t do a good job of counting in the March survey. It’s easy to miss bighorn sheep in the San Gabriels’ deep, chaparral-covered canyons during one count but then spot them grazing on open land in another count.

“It’s an inexact science,” Torres said. “It’s a bunch of scientists jumping in a helicopter.”

Loren Lutz, author of the 1988 book, “Bighorns of California,” said the aerial count is an unreliable indicator of the species’ health.

“I have some doubt about the ability of people to know what they’re looking at, how to count, where to count,” said Lutz, founder and secretary of the Society for the Conservation of Bighorn Sheep, which lobbies for protection of the animal.

State officials acknowledge that their counting system is imperfect but say they know of no better way to gauge the number of bighorn sheep, which are on the state’s list of rare and protected animals.

In July, Fish and Game biologists will hire a researcher to study past sheep census data, including how and where the animals were counted, as well as habitat changes through satellite and other high-altitude photographs, Torres said. The photographs will help biologists determine whether weather, pollution and other elements have affected vegetation in sheep habitat.

Fish and Game administrators cannot take steps to protect the sheep until they get definitive data, Torres said. Even then, there is little they can do. For instance, wildlife biologists, with U.S. Forest Service approval, could plan controlled burns to clear away thick brush for more open areas, where the sheep prefer to graze. Open space also gives the animals a better shot at spotting and avoiding predators, such as mountain lions.

Or officials could limit hiking on trails in the sheep habitat. Too much exposure to people, and sometimes their dogs, can be stressful and cause the sheep to move to outlying areas, where, perhaps, vegetation and water are not as plentiful.

But bighorn sheep are majestic animals, and favorites of hikers, said Fish and Game Warden Mark Jeter, who spots them a couple of times a year.

“Hikers will tell you they’ll stay [put], and you can get pretty close,” Jeter said.

Sometimes too close--the animals are also the target of poachers. It is illegal to hunt bighorn sheep in the San Gabriels.