Soon after Canada lynx were released into the San Juan Mountains in 1999, wildlife biologists were shocked to discover that four had quickly starved to death.

Public criticism of the reintroduction program was withering. Colorado's lynx recovery effort looked, to many people, like one giant miscalculation, and the architects of the reintroduction heartless scientists run amok.

But now, after three straight years of ever-increasing numbers of kittens being born – 101 altogether – wildlife biologists are reporting realizations of their highest hopes. The reproduction rate shows that there is both sufficient habitat and food in Colorado to support a lynx population. The animals are getting a toehold in the state where they have largely been absent for the past 30 years.

"Getting kittens was a milestone," says Tanya Shenk, lead lynx researcher for the Colorado Division of Wildlife. "Getting kittens to survive through the first winter was a milestone. Now, we're looking for another milestone when those kittens have kittens of their own."

"I think it's fulfilling our highest expectations," said Rich Reading, the director of conservation biology at the Denver Zoo and a member of the advisory panel for the lynx reintroduction. "We're not done yet, but it's definitely a feel-good story," he added.

Pointedly, researchers have been able to document only one additional lynx dying of starvation. Greater problems have been highways and shootings by people, resulting in 63 documented deaths. The total population of lynx, including surviving kittens, is now estimated at 169. That includes the 46 kittens found this year in the central and southern mountains of Colorado, all located south of I-70. Researchers suspect more kittens yet were born.

The program has cost $3 million since 1997, with $300,000 to $400,000 coming from private sources and the balance from taxes or lottery proceeds.

'TOLERABLY COMMON'

Lynx were among the many species of wildlife in Colorado that gradually disappeared during the 20th century. In a survey published in 1911, Merritt Cary of the U.S. Biological Survey reported lynx remained "tolerably common" in many mountain regions of the state. Yet, by the 1960s, owing primarily to trapping and other efforts to exterminate coyotes and predators considered a problem to livestock producers, lynx had become scarce.

The last confirmed lynx in Colorado before the reintroduction were found at Vail, where a trapper killed one, but said he saw a second one as well. However, paw prints believed to be that of native lynx have been noted from time to time since then.

The potential for lynx in an area targeted for expansion of the Vail ski area made it a point of contention in the early 1990s. At the same time, environmental activists petitioned to have the lynx listed under the Endangered Species Act in 16 states where they once existed.

Seeing that the species would likely be listed, and it was in 2000, state wildlife officials began lobbying for a reintroduction of the animals. A key discussion took place on a rafting trip down the Dolores River, in southwestern Colorado, during the summer of 1997, when various top biologists told John Mummu, then director of the agency, why they thought the effort would succeed.

Their argument was partly one of hard reality. Given the likelihood of federal protection, federal land managers would be required to protect habitat on federal lands in case lynx returned or still existed. Better to actually have the lynx and learn what they needed to survive than have to guess. There was even some hope that a successful program would allow the lynx to be de-listed in Colorado, thus giving state authorities, instead of the federal government, control of the wildlife steering wheel. The ski industry, which funded a portion of the initial reintroduction, agreed.

A secondary, more ethereal argument was that lynx existed in the area before and they had a right to return to their native habitat.

OFF TO A ROCKY START

In planning the reintroduction, biologists studied what was already known about lynx living in Canada and Alaska and made some assumptions about their habitat needs in Colorado. For the most part, the assumptions were correct, except for when and how to release the animals.

The first lynx were briefly held in captivity before being released in mid-winter, a major miscalculation. Taken aback by the starvations, the wildlife biologists fattened up the next lynx on rabbits, before releasing them in the spring. The revised procedure worked and the lynx survived.

Other educated guesses have nearly all proved out. For example, the biologists said lynx would primarily stay in the elevation range of 9,000 to 11,500 feet, where both snow cover and the spruce-fir forests are most plentiful in Colorado, and they have.

Then, after about three years, the lynx began to reproduce.

The greatest remaining unknown concerns the animals' diet. Research of the lynx now in Colorado indicates that, at least during winter, their diet consists overwhelmingly of snowshoe hare, just as in Canada and Alaska. In those places, the snowshoe hare population waxes and wanes in 10-year cycles, and the lynx population follows suit.

Nobody knows whether the snowshoe hare population behaves similarly in Colorado, says Shenk. So while the reintroduced lynx seem to be doing fine so far, the story could quickly change.

FEWER POPULATION CRASHES

Gary Patton, a wildlife biologist who formerly worked for the U.S. Fish and Wildlife Service, says he believes the habitat in Colorado is different than that in Alaska, with important repercussions. The habitat here is patchier, meaning that hare populations won't increase as much, and hence, there will be fewer lynx. But, he predicts, neither will hare populations decline as precipitously.

"You won't get the cycling," Patton says. "You will have a lower overall population over a far larger area, but on the other hand, it will be a more stable population."

Another unknown has to do with snow compaction. One theory is that snow compacted by, in particular, snowmobiles but also cross-country skis and snowshoes, could give those species competing with lynx for prey an advantage. The key advantage of the lynx in winter is their oversized paws, which allow them to more easily stay afloat in powder snow. The compacted snow provides solid footing for coyotes and bobcats, which have smaller paws than lynx, helping them hunt snowshoe hare more effectively.

This theory is being used to determine designation of recreational use in national forests elsewhere, but it's too soon to test that hypothesis in Colorado, says Shenk, because there are just too few lynx on the ground. She says an experimental research project that might have a detrimental effect on lynx would interfere with the current goal of bringing back the species.

The compatibility of lynx and ski areas is another issue far from being resolved. Both favor the same areas, which in Colorado are almost exclusively on Forest Service lands. Because ski runs are so often cut through forests of spruce-fir trees, prime lynx habitat, there is inherent conflict, points out Colorado Wildlife's Rocky Smith, a public lands watchdog for the last 25 years.

"It's an open question" as to what ski areas' collective effect on lynx will be, he says. "Maybe it's not enough to be bad. I don't know."

Says Reading of the Denver Zoo, "To a certain extent, lynx and ski areas can co-exist. But, it's like anything: It's how you manage the ski area and the ski expansion."

DANGERS OF THE HIGHWAY

As expected, cars and trucks have been a major cause of lynx mortality. Four lynx have been killed on I-70: two about a mile west of the summit of Vail Pass and two more five or six miles east of Eisenhower Memorial Tunnel. As well, various others have been struck on Red Mountain Pass, Wolf Creek Pass and other roads.

These deaths were no surprise to Patton, the former federal wildlife biologists who identified the two I-70 sites as likely lynx travel corridors. Overpasses to accommodate travel by lynx and other species have been proposed there and in other sites in Summit County.

The theory is that lynx stay near to forest cover as they move around. In both sites of mortality on I-70, trees crowd the edge of the highway.

"It's not that there's any magical charm to those areas," says Shenk, referring to locations on I-70 where lynx have been hit.

"It's a matter of the forest meeting the forest on the other side of the highway. That's how I think lynx choose those areas."

KEEPING TRACK

Most of the lynx released still wear the radio-collars researchers placed on them for tracking purposes, and have been tracked in the Keystone and Copper Mountain areas. Current plans call for 30 more lynx to be released in Colorado over the next two years. Seven lynx kittens were radio-collared this year, allowing Shenk and her research associates to begin mapping the social interactions of the animals for the first time. Those interactions include such things as how far males travel after mating and how quickly offspring can have young of their own.

Even though the project is in its early stages, Patton proclaims the reintroduction of lynx a major success and a turning point for the Colorado Division of Wildlife. Before, he says, the agency was driven to sell hunting and fishing licenses, which meant the agency showed the most interest in stocking the wildlife that could be shot or hooked. Patton concedes that the DOW did restore otters, which are not hunted, and it made major efforts to recover greenback cutthroat trout and the boreal toad. But in restoring lynx, the agency had to spend what Patton calls "political capital" in the face of great public criticism. If repopulating Colorado with lynx is not yet assured, the story so far has been one of success.