Colorado-Born Lynx Has Twin Kittens

This is a photograph provided by the Colorado Division of Wildlife shows two male lynx kittens June 17, 2006, in the southern mountains near Durango, Colo. The kittens are the first documented by the Colorado Division of Wildlife that were produced by a lynx that was born in Colorado. Because the eyes of the kittens were not open when this photograph was taken, researchers estimate that the kittens were no more than a week old at the time. (AP Photo/Colorado Division of Wildlife) (AP)

DENVER -- A lynx born in Colorado has given birth to two kittens, a major milestone in the state's ambitious attempt to reintroduce the elusive cats, researchers said Tuesday.

It was the first documented case of a Colorado-born lynx giving birth since the reintroduction program began in 1999. The cat, born in 2004, gave birth to two males in mid-June, buoying hopes that lynx will develop into a self-sustaining population in the state.

"From here on out, we're just waiting to see if we can maintain a good survival rate," said Tanya Shenk, the Colorado Division of Wildlife's lead researcher on the program.

The news was tempered, however, by a dramatic reduction in the number of births this year. Colorado Division of Wildlife researchers found four dens with a total of 11 kittens, down from 18 dens with 50 kittens last year.

Biologists are puzzled by the decline and studying possible reasons. Shenk said one possibility is that recent releases of adult cats could have disrupted the cats' social structure. But that is only speculation, she added.

"We're not seeing any indication of the animals being in poor body condition. There seems to be sufficient prey," she said.

The four dens where kittens were found were normal, Shenk said.

Researchers believe other kittens were born but not counted this year because their mothers do not have radio collars and cannot be tracked.

"I don't think we've found all the kittens any of the years," Shenk said.

The last two winters, biologists and trackers found additional kittens missed during the summer count. They typically start searching for newborn lynx in mid-May after flight crews monitor the cats' movements from the air.

Biologists take genetic and blood samples from the kittens and put microchips under their skin so they can identify them if they catch them again later.

The animals' death rate hasn't increased, and most of the cats are staying in established territories, said Rick Kahn, the Division of Wildlife biologist who heads the lynx program.