Lynx Making a Comeback in Minnesota
BRIMSON, Minn. Lynx No. 13 growled a warning at the researchers who came to weigh and tag her four kittens. The mother lynx watched from 20 feet away, never coming closer but never leaving, as the scientists poked and prodded the 3-week-old kittens, who received ear tags as part of a study that could determine the fate of her species in Minnesota.
The researchers then placed the spotted-gray kittens back under the fallen tree their mother had picked for their den, and quietly walked away.
"We try to keep our time in here to a minimum, keep the intrusion as little as possible. ... But they really don't seem to have any long-term reaction to us," said Ron Moen, lead researcher for the lynx project for the Natural Resources Research Institute of the University of Minnesota Duluth.
It was only five years ago that some biologists declared lynx all but eliminated from Minnesota. But when they started looking hard, researchers found lynx across St. Louis, Lake and Cook counties of northeastern Minnesota. Last year, a lynx den was discovered in Minnesota for the first time in more than 20 years.
Moen said it's possible that there were indeed no lynx or perhaps just a few in Minnesota in the 1990s. But there's no question the wildcat is making a comeback now.
The presence of more than 60 individual lynx has been confirmed in the state through DNA testing. More lynx DNA samples await laboratory confirmation. And at least four female lynx are currently raising kittens to add to the numbers.
All those confirmations have come in just the three northeasternmost counties. Researchers now have money to expand their search westward across the state and will start looking later this year.
"They've been found as far west as Red Lake for sure, and one was hit by a vehicle near Hinckley. Their range is fairly broad now," said Ed Lindquist, biologist for the Superior National Forest.
Lynx were once common in Minnesota's northern forests. Their numbers rose and fell, apparently following the cycles of their favorite food, snowshoe hares. The cats were heavily trapped until the 1970s.
But after a relative peak in the 1970s, lynx numbers crashed. The decline appeared to coincide with the fall of hare numbers and other factors, including heavy lynx trapping in Canada. That trapping may have reduced lynx populations in southern Manitoba and Ontario, from which new lynx could stage a push back into Minnesota.
But lynx didn't rebound even when hares did. The state ended trapping in 1984. In 2000, the federal government added lynx to the threatened species list across the United States because lynx numbers also had crashed in the mountain west and in Maine.
One factor might be competition from other predators, especially bobcats. Another theory was that global climate change, which is pushing animals such as opossums and raccoons farther north into northern Minnesota, may also be pushing lynx north, out of the state. Lynx have an advantage over other hare predators with their ability to run on deep snow. But in years of little snow, a lynx has less of a competitive advantage.
None of those theories seems consistent with the lynx rebound in Minnesota, researchers say.
"I don't think we really know why we're finding so many now," Lindquist said. "We have more hares. But that's not all of it."
The federal government is paying for research and developing a plan to protect lynx to ensure lynx won't become extinct in Minnesota. The government is under court order to put a habitat plan in place later this year to foster the cat's recovery. The current lynx research will probably be the basis of that plan.
Global positioning system collars put on 30 lynx over the past three years have given researchers more than 10,000 location points where lynx have spent time in Minnesota. Four times a day the GPS collars reveal the location of each collared lynx.
Researchers now know that lynx hunt hares in thick stands of young forest that have been logged or burned in recent years. But lynx also spend ample time, especially when having litters, in woods with big, old trees that block the sun.
Determining how much of each habitat is needed will be critical, Moen said.
Lynx No. 13 settled into tangled patch of blown-down spruce and balsam in the Superior National Forest near Brimson, a town about 20 miles northwest of Two Harbors.
It was trapped and fitted with a radio transmitter collar in March 2004. It had a litter of five kittens last summer and now has four more. Three of last year's kittens are still alive. Researchers guess the 25-pound female is now about 4 years old.
Because they're living in a thick pile of downed trees, and because the newborns are nearly odorless, the kittens have a good chance for survival.
Trains, trucks and traps have been the largest cause of death for radio-collared lynx in the project. Only one has been verified as killed by another animal, a fisher, a mammal related to the weasel.
That makes people the biggest threat.
"They are notoriously easy for trappers to trap. And they seem to spend a lot of time around roads ... and at some point they're going to get unlucky," Moen said.
Source: Associated Press