Article by Allen Best
Wildlife – October 2005 – Colorado Central Magazine
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 scornful. Colorado’s lynx recovery effort looked to many people like one giant miscalculation and the architects of the reintroduction like heartless scientists run amok.
But now, after three straight years of ever-larger numbers of kittens, 101 altogether, wildlife biologists are realizing their highest hopes. Lynx reproduction shows that there is both sufficient habitat and food for the animals. They are getting a toehold in a state where they have been largely 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.”
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.
“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.
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 — and researchers suspect that even more kittens have been born.
The program has cost $3 million since 1997, with $300,000 to $400,00 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 other predators considered a problem to livestock producers, lynx had become scarce.
The last confirmed lynx in Colorado was at Vail. A trapper killed one, and said he’d seen a second one as well (and paw prints of what was believed to be native lynx have been noted from time to time since then — but no irrefutable evidence of surviving lynx has been found).
The potential for lynx in an area targeted for expansion of the Vail ski area made the rarity of the animal a point of contention in the early 1990s. During that time, environmental activists petitioned for listing the lynx for protection under the Endangered Species Act in 16 states outside of Alaska where they had once existed. That effort finally succeeded in 2000.
By then, state wildlife officials had already started lobbying for a reintroduction. During the summer of 1997, a key discussion took place on a rafting trip down the Dolores River, in southwestern Colorado. Various top biologists told John Mummu, then director of the agency (now retired to the Durango area), why they thought the effort would succeed.
Their argument was partly one of hard reality. Given the likelihood of 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 would 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.
Stumbled at the start
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. One of the only guesses that came up short concerned 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, the wildlife biologists fattened up the lynx on rabbits before releasing them in spring. With 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.
Also as predicted, lynx have largely stuck to forested areas.
And finally, it took about three years for the lynx to begin reproducing.
The greatest unknown has to do with their diets. Research on 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 hare plummet.
Fewer population crashes
Gary Patton, a wildlife biologist who formerly worked for the U.S. Fish and Wildlife Service, says he believes the habitat is different in Colorado than in Alaska, with important repercussions. The habitat is more patchy here, which means that hare populations won’t increase as much, and hence there will be fewer lynx. But neither will hare populations 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,” says Patton.
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 an advantage over lynx. The tracks compact the snow, providing solid footing for coyotes and bobcats, which have smaller paws. This could make them more competitive with lynx in chasing snowshoe. The key advantage of the lynx is its oversized paws, which allow it stay afloat in powder snow.
This is the theory used in designating 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 unresolved issue. Lynx and ski areas both favor the same areas, which in Colorado are almost exclusively on Forest Service land.
Because ski runs are so often cut in forests of spruce-fir trees, 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” he says, concerning what the ski areas’ impact on lynx will be. “Maybe it’s not enough to be bad, I don’t know,” he says.
Says the Denver Zoo’s Reading, “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.”
Squashed on I-70
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 the Eisenhower Memorial Tunnel. Various others have been smashed on Red Mountain Pass, Wolf Creek Pass and other roads.
These deaths were no surprise to wildlife biologists. Overpasses to accommodate travel by lynx and other species have been proposed there, as well as several other sites in Summit County.
The theory is that the lynx hew to the forest cover as they travel. In both 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.”
Most of the lynx still have radio-collars, and researchers have thereby tracked the lynx in the Keystone and Copper Mountain 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. So 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 major success and 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 with species 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. Yet the agency worked out the problems and persevered.
If the repopulating of Colorado by lynx is not yet assured, the story so far has been one of success. “This is a big deal,” Patton says, “and I think very few people understand it.”
Allen Best writes from the Front Range and Eagle County.
