Moose Mystery

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Moose Mystery

Postby PaddlerJimmy » Tue Apr 24, 2007 4:08 pm

The Moose Mystery
Apr 19, 2007 10:45 pm US/Central

Bill Hudson
Reporting


(WCCO) With a toot of his horn, Orvis Lunke mimics a moose's bellow. He's trying his best to call one into view but on Minnesota's Gunflint Trail, deep into the Superior National Forest, he's having little luck.

Orvis trudges across a freshly logged plot of land and points to some birch browse.

"They've been way up here, nipping the tops off," said Lunke.

Despite the signs of recent moose activity in the area, actual sightings of the giant woodland animals are becoming rare. In years past, the retired Minnesota Department of Natural Resources forester has seen more than his share of moose. The Gunflint Trail, a long popular route that cuts a swath through the state's most rugged wilderness, has long been a haven for moose.

"Not this year," Orvis said, "Not a lot of moose in this area by the way it looks."

His observation is alarming because it reflects what's becoming a statewide trend: Minnesota's moose population is in serious decline. Aerial surveys by the DNR have been counting moose for over 40 years.

In 2006, that survey estimated the moose population in the northeastern part of the state at 8,400. The same area surveyed this winter counted nearly 2,000 fewer moose. That's a drop of 23 percent.

Mark Lenarz is the DNR's lead moose researcher. While understandably concerned over the numbers, Lenarz is also confused.

He said what's most baffling is that "there's any single cause for this mortality we're seeing in a number of different places."

For instance, the state's northwestern region was also once a haven for moose and had somewhere near 4,000 animals in the 1980s. This year's aerial survey found just 84.

Lenarz said tissue samples from some of the moose carcasses are being tested to determine cause of death, but are often times inconclusive.

Referring to the necropsies performed at the University of Minnesota, Lenarz said, "they found the approximate cause of death was parasites or malnutrition … moose are starving to death or suffering the side effects from the parasites."

Certainly, the state's growing timberwolf population accounts for some of the moose mortality but nowhere near the number that's being seen. Moose are also plagued by such parasites as brainworm, liver flukes and winter ticks, but they too aren't found in all the moose carcasses being tested.

"Perhaps it's some other parasite or disease we haven't identified yet," said Lenarz.

However, what's really raising eyebrows among wildlife biologists is an apparent correlation between the rapid moose decline and northern Minnesota's warming climate.

Weather data shows that the region's summer temperatures have increased along with higher humidity, dew points and overnight lows. That is a concern because moose are a "cold climate" animal, surviving best in Canada, Alaska and Northern Scandinavia.

Lenarz said the evidence seems to suggest that global warming may be a contributing factor in the moose's decline. When winter temperatures rise above 23 degrees Fahrenheit, moose breathe faster. In the summer when it gets above 67 degrees, they begin panting like a dog and will only find relief from the heat by spending most of their day in swamps, rivers and lakes.

He compares it to a human wearing a snowmobile suit all summer long. Lenarz said in hot weather, moose tend to feed less and put on less fat that is vital for their winter survival.

"Basically, they don't do well in hot conditions," he adds.

A higher respiration rate and less time feeding puts an added stress on the animals that can make them more prone to parasites and disease.

The DNR is working with the 1854 Treaty Authority, its Native American counterpart, to conduct more research into moose mortality. In a quest to find a culprit, biologist Andy Edwards continues to track what remains of the original 116 radio-collared moose. Already, two-thirds of the collared moose in the study have died.

"When a pilot is up doing his weekly tests over the area hears a difference in the beeping signal, we'll know that that animal is likely dead," said Edwards.

That's when crews locate the carcass on the ground and send tissue samples to the U of M lab.

Over the past five years, mortality among radio collared moose averaged about 22 percent per year. Last year, that soared to 34 percent.

On top of that the survival rate of moose calves is dropping to an all time low. In a normal year, 50 to 60 calves in 100 will survive the first year. The most recent data show a survival rate of just 29.

In a recent flight over the remote Superior National Forest near Isabella, Edwards spotted two moose from the WCCO Sky 4 helicopter. The first was so tick-infested most of its hair was rubbed off. The other was a fresh moose carcass that becomes more data for him and more food for hungry wolves.

However, it's not just data that shows the decline. Each spring Lunke, the moose caller, scours the woods, looking for those huge antlers that all bull moose shed before growing them new ones.

"Now they're just harder to find , because there's just fewer of them," said Lunke.

In the heyday of Northern Minnesota's moose population, it was nothing for Lunke to find 80 of these sheds, in a single spring in the woods. Last year he found only 15.

It's troubling news along the main streets and backwoods taverns stretching from Ely to Grand Marais. Moose have always been a huge attraction for summer tourists.

Larry Schanno is the owner of Our Place on Highway One in Finland.

"There are more people that come in here and asking me where they can see a moose than where to fish," said Schanno.

He said the locals are referring to the mystery as "drop dead disease."

"Research tells you what, they don't know, they can't tell you," said Schanno.

That's why more research into climate change and mortality will be needed, if biologists are to solve this, "moose mystery."


http://wcco.com/topstories/local_story_109223634.html
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The case of the missing moose

Postby PaddlerJimmy » Sun Feb 24, 2008 12:35 pm

The case of the missing Minnesota moose
By BILL MCAULIFFE, Star Tribune

February 23, 2008

ISABELLA, MINN.

Moose 294 lay in deep snow in the scrubby woods, eyes half open in the bright February sun. Huffing steadily, her coat a shimmering walnut brown, she might have been enjoying a winter siesta, but for the pink-tufted tranquilizer dart lodged in her backside.

For researchers Mark Keech and Tiffany Wolf, though, this was no time to relax. From the time Keech had fired the dart from a helicopter into the fleeing 850-pound moose, Keech and Wolf had about 30 minutes for a full work-up.

Wolf, an associate veterinarian with the Minnesota Zoo, withdrew several tubes of blood. Keech, a research biologist, sliced out the barbed dart and yanked out an incisor. Wolf collected hair and fecal samples. Keech riveted an air tag through the moose's ear and screwed on a heavy leather collar equipped with a radio transmitter.

Time was running out. Wolf injected two drugs to reverse the tranquilizers and the researchers scrambled off about 20 yards. As if on cue, Moose 294 gave a little groan, stumbled, rose grandly to her feet, collected her wits and clattered off through the brush.

"Good luck!" Keech called out.

Good luck indeed. Something strange is killing the moose of northern Minnesota, and wildlife scientists hope Moose 294 and others like it can provide some clues as to why. The task is urgent: In the course of a few years, the number of moose in northwestern Minnesota has plummeted to near extinction.

What the researchers find out could shed light on broader changes in the North Woods, where the moose is an iconic part of the landscape and the web of life.

"When you think of northern Minnesota, you think of the North Shore, the Boundary Waters, wolves, loons and moose," said Mike Schrage, wildlife biologist for the Fond du Lac Band of Lake Superior Chippewa, which is partnering with the Minnesota Department of Natural Resources and the 1854 Treaty Authority in studying the northeast moose herd. "They're part of our identity. You pick up a Duluth Pack, and what's the logo? A big bull moose."

Scientists say that the moose are dying from "tipover disease," less a diagnosis than a description of how moose simply weaken and crumple to the ground, often to be finished off by wolves or other predators. Minnesota moose seem to be dying when and where they shouldn't -- in the prime of life, or in the fall, when they should be fat, and amid plenty of food. The causes are still largely unknown.

It might be due to parasites they've picked up from an exploding deer population. It might be a complication of heat stress, induced by a climate that's gotten too warm too fast. It might be combination of those and other factors.

850-pound canary?

The fate of the state's largest herbivore is about more than postcard imagery, Schrage and others say. The moose may be an outsized canary in a coal mine, representative of a struggle facing many other animals whose home ranges and climate are changing, said Dennis Murray, a professor of terrestrial ecology at Ontario's Trent University.

"We don't know those other species as well as moose," Murray said. "Therefore those changes aren't as apparent."

Researchers have been studying the northeast moose since 2002. Of the 114 they've collared and tracked since then, only 28 were still standing this year. Of the other 86, more than half died of unknown causes.

No moose were collared the past two years because there wasn't any money. Now a $200,000 federal Tribal Wildlife Grant will pay for research through the winter of 2010-11. The Minnesota Deer Hunters Association has also contributed.

Researchers aren't wasting time. Their goal this year was to put collars on 35 moose, all cows, so they can focus on pregnancy rates.

On Tuesday, months of planning turned into action. The study partners were joined at the Ely Municipal Airport by the zoo's Wolf, who handles the tranquilizers and anti- dotes, and two Alaskans in their fourth year on the job. Keech was "vacationing" from his regular job with the Alaska Department of Fish and Game, and helicopter pilot Scott Gibbens is a retired state trooper who's been tracking wildlife by air for 10 years. Ground support included a fuel truck and a pair of snowmobiles.

It was just luck that the overnight temperature hit 24 below at Ely.

"Hard on people and equipment, but good for the moose," Schrage said.

DNR pilot Al Buchert was the advance scout, flying a single-engine airplane over 30 plots of clearcut, swamp and forest. Buchert relayed moose sightings over the radio to Gibbens. The helicopter swooped down toward the moose, sometimes within 15 yards.

Keech leaned out of the craft with a rifle much like a .22 and fired a tranquilizer dart. He rarely misses.

Within five to seven minutes, the drug brought the moose to its knees. Gibbens landed the helicopter nearby, and Keech and Wolf tromped through the snow to the moose's side to begin their work.

Researchers look for many things in the moose samplings. Blood samples can yield evidence that the moose has tried to fight off a brainworm invasion, or has other diseases, or lacks key trace elements or heavy metals. The feces (extracting them by hand is "the glory part of the job," Wolf said) can reveal whether the moose is pregnant or has parasites. The hair contains DNA information, which has already been helpful in busting at least one poacher. And the tooth, like a tree, has rings that reveal the moose's age.

Cool retreats

This year, the moose collars will carry a new device -- a thermometer to record the temperature in the moose's surroundings. Schrage and DNR wildlife researcher Mark Lenarz said that may help determine whether moose are finding places in the woods -- "microclimates" -- where they can stay cool enough, winter and summer, to stay healthy. If they can prove that theory, that could lead to forestry and wildlife management efforts to protect and enhance such areas.

Lenarz pointed out that global warming, or at least the winter warming in northwestern Minnesota in the past 40 years, can be regarded as a "proximate" cause of increasing moose deaths. That means it's a context that creates the more direct causes or vulnerabilities, much like alcoholism might lead to a person's death from liver failure.

Mean midwinter temperatures in northwest Minnesota increased about 11 degrees from 1961-2001, astonishing by most climate change measures; Lenarz said researchers are still examining the trends in the northeast. Schrage said he believes mild winters and longer growing seasons are a threat to the northeast moose, but they don't explain everything.

"It's complicated in between a warm climate and a dead moose," he said. "I don't think I'm ever going to walk up to a dead moose and say, 'Oh, it died of heat stress.' There's a lot that happens in between."

A test case

Even a dead moose can help the researchers. Last December, a moose stumbling near a highway close to Side Lake was shot by a DNR warden. Two days later the moose was on a table at the Veterinary Diagnostic Lab at the University of Minnesota's St. Paul campus. A team led by pathologist Dr. Arno Wunsch-mann had scalpels in hand.

The necropsy was a rare opportunity to examine a dead moose before predators or decomposition damaged it.

The moose appeared fairly healthy, if a bit undernourished for the time of year. Wunsch-mann sliced the moose's brain, spinal cord and pituitary gland into samples that would be further processed into slides for study under a microscope. After looking at 50 slides for three hours over two days, Wunschman had a cause of death: brainworm, a parasite that has passed from deer to moose and burrows through their spinal column and brains. White-tailed deer, however, are largely immune to the damage.

End of story? Not quite. Blood sampling of collared Minnesota moose, Lenarz said, has shown that between 16 and 18 percent have been exposed to brainworm. That's less than the annual non-hunting mortality rate, and in any case it doesn't indicate anything about how successfully moose might resist the parasite and its effects.

This week's mobilization ended Friday with 34 moose collared, one short of the goal because a radio on one collar didn't work. The samples from the darted moose will take months to analyze. Now that she has a radio collar, Moose 294 will be tracked weekly by the DNR. By all appearances, she's healthy and even a little fat, Keech and Wolf noted in their encounter.

Minutes after she pushed off through the thicket of small maple and poplar, Gibbens and two passengers spotted Moose 294 in a clearing, already nearly 300 yards away. Alert to the helicopter overhead, she darted toward cover, high-stepping through the deep snow toward an uncertain future.

Bill McAuliffe • 612-673-7646
http://www.startribune.com/local/158958 ... page=1&c=y
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