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Jan. 13, 2001
By Gail Binkly Two years after a beginning marred by early failure and political controversy, Colorado’s lynx-reintroduction program has proven remarkably successful, researchers say. It’s too soon to tell whether the effort will produce a self-sustaining population of the tawny, elusive animals, but experts are optimistic. "We received some early criticism, but we’re seeing that lynx are doing well," said Division of Wildlife spokesman Todd Malmsbury. "And we’ve learned an enormous amount." The lynx, a bobcat-sized predator that dwells in snowy forests, was declared a federally threatened species on March 21, 2000. Although common in Canada and Alaska, lynx have been declining for decades in the Lower 48 states. Breeding populations are now believed to exist only in Maine, Montana and Washington, out of the 14 states that originally had them, according to the U.S. Fish and Wildlife Service. The last lynx documented in Colorado before the reintroduction was illegally killed near Vail in 1973.
But, in February 1999, the Colorado Division of Wildlife began releasing lynx into the southern San Juan Mountains. A total of 96, all trapped in Canada or Alaska, were turned loose near Wolf Creek Pass during the early months of 1999 and 2000. Twenty-nine of the animals have died, a mortality rate of approximately 30 percent. That’s substantially lower than in most predator reintroductions, researchers say. "With carnivore programs, it’s normal to have a mortality rate of 50 percent or higher," Malmsbury said. When black-footed ferrets were reintroduced into the Dakotas, the mortality rate was more than 80 percent in the first year, yet the effort eventually was successful, he said. Colorado’s river-otter reintroduction had a mortality rate of about 40 percent, but succeeded well, according to biologists. "Experts both inside and outside the division, and in other states and Canadian provinces, who have been following the program say they’re frankly surprised and pleased that we’ve had as low a mortality rate as we’ve had to date," Malmsbury said. Forty-one lynx were released in 1999, and 22 of those have died, DOW statistics show. But of the 55 lynx released the next year, only seven have died. They died from a variety of causes: Seven starved, four were shot, four were struck by cars, five died of unknown causes not related to starvation, five died of unknown causes, two were killed by plague, one died of some unknown trauma, and one was evidently killed by a bobcat. The most recent death occurred on Dec. 24, 2000, when a healthy female lynx was apparently hit by a vehicle on Highway 550 near Red Mountain Pass. Another six of the felines, all males, are missing, meaning they haven’t been tracked by radio collar for more than 1 1/2 years. However, that doesn’t necessarily mean they’re dead; one female that had been missing since June of 1999 turned up a year later south of I-70 in fine shape. Significantly, researchers say, six of the seven starvation deaths occurred in the first year. When the first lynx were captured in British Columbia, biologists believed it would be best to hold the animals for as brief a time as possible. After the lynx reached Colorado, they were kept just a few days at the holding facility near Del Norte. But four of the first five soon starved, so biologists began keeping the cats for at least three weeks, until they had increased their weight by 25 percent or more. Starvation soon ceased to be a major problem. "There were so many unknowns," Malmsbury said. "There’s no textbooks for ‘Reintroduction into the Southern Rockies of the Lynx’." The lynx effort came under fire early on — both from animal-rights advocates who said it was cruel to bring the cats here from Canada just to starve, and from property-rights proponents who feared the program would cause restrictions of recreation or grazing on public lands. But both criticisms were unwarranted, DOW officials say. The lynx transported from up north were in some ways given a new chance, according to Jim Olterman, the Division of Wildlife’s senior terrestrial-wildlife biologist for western Colorado. In the far north, lynx populations swell and then crash in synch with the 10-year cycle of the snowshoe hare, the lynx’s favorite prey. The lynx captured in 1999 and 2000 were taken when their population was at its peak. Now, many animals are starving as snowshoe-hare numbers plummet, Olterman said. "They (the transplanted lynx) probably got a break being here now instead of up there," he said. And the division’s reintroduction effort occurred independently of the lynx’s listing as threatened, which was done by the Fish and Wildlife Service, Malmsbury pointed out. "Any actions that will be taken by the federal agencies as a result of that listing are not related to our effort," he said. "They would have occurred anyway." The knowledge gained from Colorado’s effort will help other agencies, he said. "There’s less likelihood that people will have to guess at potential habitat impacts as related to lynx" because of research that has been done here. "We have learned an enormous amount," Malmsbury said. "We’re learning so much so quickly. Colorado is the source for lynx information in the Lower 48 states right now." The majority of the lynx have remained around the release area, according to Tanya Shenk, a DOW mammals researcher who heads a team of six temporary employees who are snow-tracking the animals to document their behavior. The lynx are also tracked by radio and satellite signals from their collars. In the first year, many lynx roamed widely, but most are now within the San Juans, she said. Their "core" area extends from the New Mexico border north to Gunnison, as far east as Monarch Pass and as far west as Taylor Mesa, she said. Several have roamed into Montezuma County; one was shot in the Glade on Oct. 31, 1999, by a hunter from Louisiana, who was fined $18,000. A total of 57 females and 39 males were released, Shenk said; 35 percent of the females died vs. 23 percent of the males. Researchers snow-tracking the animals say 75 percent of their documented kills have been snowshoe hares, 24 percent red squirrels. The lynx also are devouring some small rodents, but that’s difficult to prove because they are eaten whole, Shenk said. One major question remains unanswered: Will Colorado’s lynx reproduce? Trackers have kept a sharp eye out for any sign of kittens following female lynx, but have seen none so far. "We have not documented any reproduction, which we really didn’t expect this year," Olterman said. The animals’ density was so low at first that it would have been difficult for them to find each other to mate, he explained. Breeding season starts in late March, Shenk said, and gestation is about 63 days. "We’ll be monitoring the females very closely for stationarity, as if they’re attending a den," she said. "We’re looking forward to spring," Olterman agreed. "Hopefully there will be some litters. We almost have to have some. "I believe there will be. The density is much better than it was a year ago." Researchers didn’t necessarily expect to see reproduction yet, Malmsbury said. But, since there probably won’t be any more lynx releases in Colorado, the success of the program now depends on the animals producing kittens who can survive on their own. "It’s going to be five or 10 years before we can say this looks like it’s going to be a success in the long term," Malmsbury said. "We recognize that it still may not be successful. But given the difficulty, we’re pleased with our progress to date." |
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