Lynx recovery makes strides
Biologists increasingly confident after three years of kittens

Vallecito Creek flows out of the Weminuche Wilderness early this week. The San Juan Mountains are prime lynx habitat and have been one focus of increasingly successful recovery efforts./Photo by Todd Newcomer.

by Allen Best

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

Public criticism was on the rise, and 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-larger numbers of kittens, 101 altogether, wildlife biologists are reporting realizations of their highest hopes. The reproduction shows that there is both sufficient habitat and food for the lynx. They are getting a toehold in the state where they have largely been absent for 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.”

Rich Reading, director of conservation biology at the Denver Zoo and a member of the advisory panel for the lynx reintroduction, agreed, saying, “I think it’s fulfilling our highest expectations. We’re not done yet, but it’s definitely a feel-good story.”

Researchers have been able to document only one additional lynx dying of starvation. Greater problems have been highways and shootings, which have resulted 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 southwestern mountains of Colorado. Researchers suspect more kittens yet were born.

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 cpredators considered a problem to livestock producers, lynx had become scarce.

The last confirmed lynx in Colorado were located in the vicinity of Vail, and 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. During the same time, environmental activists petitioned for listing the lynx for protection under the Endangered Species Act in 16 states outside of Alaska where they once existed. That effort finally succeeded in 2000.

Seeing that the species would likely be listed as endangered, state wildlife officials began lobbying for a reintroduction. A key discussion took place on a rafting trip down the Dolores River during the summer of 1997. Various top biologists told John Mummu, then director of the agency, why they thought the effort would succeed.

Their argument partly was one of hard reality. Given the likelihood of a federal listing, federal land managers would be required to protect habitat on federal lands just in case lynx returned or still existed. Better to have lynx and see what they need to survive, went the argument, than have to guess. There was even some hope that a successful program could allow the lynx to be delisted 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 before, and they had a right to return. In other words, it was time to right old wrongs.

In planning the reintroduction, biologists studied what was known about lynx in Canada and Alaska and made some assumptions about their habitat needs in Colorado. Nearly the only guess that came up short was when and how to release the lynx.

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

Other educated guesses have nearly all proved out. For example, they said lynx would primarily stick to the elevation band of 9,000 to 11,500 feet, where both snow cover and the spruce-fir forests are most plentiful in Colorado. They have. And finally, it took about three years for the lynx to begin reproducing.

DOW researcher Grant Merrill spotted this lynx kitten while investigating a den site in the San Juan Mountains used by a female that was released in 2000. /Courtesy photo.

The greatest unknown has to do with their diets. Research of the new lynx in Colorado indicates that, at least during winter, the lynx diet consists overwhelmingly of snowshoe hare, just as in Canada and Alaska. But in those places, snowshoe hare populations wax and wane in 10-year cycles, and populations of lynx similarly wax and wane a few steps behind.

Nobody knows whether snowshoe hare populations behave similarly in Colorado, says Shenk. In other words, while the lynx reintroduced so far seem to be doing fine, the story could change if the population of snowshoe hares plummets.

Fewer population crashes

Gary Patton, a wildlife biologist who formerly worked for the U.S. Fish and Wildlife Service, says he believes the habitat more patchy in Colorado than in Alaska. That means that hare populations won’t increase as much, and hence there will be fewer lynx. But neither will hare populations won’t decline as precipitously, he predicts.

“You won’t get the cycling. You will have a lower overall population over a far larger area, but on the other hand, it will be a more stable population,” he says.

Yet another question has to do with snow compaction. One theory is that snowmobile tracks in particular but even cross-country ski and snowshoe tracks could give other, competing species of lynx an advantage, providing solid footing for coyotes and bobcats. This may make them more competitive with lynx for a fixed supply of snowshoe hares. The key advantage of the lynx is its oversized paws, which allow it to more easily stay afloat in powder snow.

This theory dictates recreational use of the national forests, 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.

Compatibility of lynx and ski areas is an issue similarly far from being resolved. Lynx and ski areas both favor the same areas, which in Colorado almost exclusively is on Forest Service land. Because ski runs are so often cut in forests of spruce-fir trees, there is inherent conflict, points out Colorado Wild’s Rocky Smith, a public lands watchdog for the last 25 years.

“It’s an open question whether ski areas in their collective effect on lynx will be. Maybe it’s not enough to be bad, I don’t know,” he says.

Clashing travel corridors

As expected, cars and trucks have been a major cause of lynx mortality. Four lynx have been killed on I-70 and several others have been hit on Red Mountain Pass, Wolf Creek Pass and other area 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. The theory is that the lynx keep to the forest cover as they travel. In the sites of mortality, trees crowd the highway.

“It’s not that there’s any magical charm to those areas,” says Shenk, referring to the areas where the lynx were squashed on I-70. “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.”

Current plans call for only 30 more lynx to be released into Colorado during the next two years. In the meantime, seven lynx kittens were radio-collared this year, meaning that Shenk and her research associates will, for the first time, be able to begin mapping the social interaction among lynx, including such things as how far afield males go after mating and how quickly offspring can have young. “We don’t even know what we’re going to find out,” says Shenk.

Even short of long-term success, Patton proclaims the reintroduction a turning point for the Colorado Division of Wildlife. Before, he says, the agency was driven to sell hunting and fishing licenses, which means that it showed the most interest in stocking the landscape that could be shot or hooked.

Patton concedes that the DOW did restore otters, which are not hunted, and it also made major efforts to recover greenback cutthroat tout 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 the repopulating of Colorado by lynx is not yet assured, the story so far has bene of success.

“This is a big deal,” he says, “and I think very few people understand it.”



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