January 23, 2006
The Associated Press
CBS Denver

ROCKY MOUNTAIN NATIONAL PARK —As tough as they look and are, bighorn sheep may be in trouble.

“We’ve got a problem,” Judy Visty, a biologist at Rocky Mountain National Park told a Denver newspaper. “There does appear to be a trend that reproduction is not enough — especially on the east side of the park — to maintain a sustainable population,” she said.

“Lambs aren’t surviving. Diseases periodically devastate herds and we’re not entirely sure why,” said Mark Miller a Colorado Division of Wildlife veterinarian.

Some Wyoming herds are having similar problems, said Greg Anderson of the Wyoming Game and Fish department. “They’re real hardy animals when it comes to weather,” Anderson said. “But they seem to not be real adapted to some of the diseases that have been introduced.”

Last year, state biologists began a study of the bighorn herd in Poudre Canyon outside Fort Collins and found a lamb-to-ewe ratio of fewer than 20 lambs per 100 ewes. A healthy population would have at least 40 per 100, said, wildlife division biologist Janet George.

A Georgetown herd had a lamb-ewe ratio of 40 or 60 five years ago, last year it was 25.

Unlike other species who have been making comebacks from over-hunting and other problems, the bighorn population is stagnant. Scientists plan new studies to more fully identify the problem. Biologists have already begun studies at the park of its estimated 350 bighorn, up from 200 15 years ago when pneumonia and other diseases killed many.

Up to 4,000 bighorn lived in the park area a century ago.

“I don’t think sheep are going to be gone in five years, but we’re trying not to drop the ball on them,” Visty said.

“This is not an animal we want to lose.”

There isn't a single killer disease; initial results from a Colorado State University study indicated they are infested with numerous diseases. They range from bovine viral diarrhea to lungworm and Pasteurella bacteria and can interact with each other as well as with other factors stressing the animals, said Miller.

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