March 8, 2006--It's shaping up to be a lean year for the wolves and moose of Isle Royale National Park.
The number of moose has sunk to 450, the lowest since researchers began tracking their numbers on this wilderness Lake Superior archipelago. Now in its 48th year, the project is the world's longest-running study of predator-prey relationships.
"The moose are probably hurting because there are so many wolves," said Assistant Professor John Vucetich, who co-leads this ongoing Michigan Technological University investigation with Professor Rolf Peterson. While moose have declined, wolf numbers have been on the rise for the past several years, topping out at 30 in 2004-05 and holding steady this year.
For the last few years, the island's moose have been weakened by a plague of ticks, which distracted them from feeding and caused hair and blood loss. The ticks do not attach to humans, but they have been a bane for the moose, making them easy prey for the wolves, who have had relatively easy pickings since 2002-03, when the moose population stood at 1,100. Now, however, most of the older moose have died, so wolves have had to rely even more than usual on moose calves.
"We had two dozen moose die while we were there this winter," Peterson said. "Moose are really going to go down, unless the wolves back off."
The numbers only tell part of the story. As their primary food source dwindles, Isle Royale's wolf packs are reacting to the strain.
"They're showing signs of turmoil and chaos," Vucetich said.
In addition to a handful of lone animals, Isle Royale is home to three wolf packs: the Middle Pack, the East Pack and the Chippewa Harbor Pack. This year, the East Pack has been trespassing on the Chippewa Harbor Pack's territory, and Vucetich witnessed some of the hostilities while on a routine observation flight over the area Jan. 31.
The Chippewa Harbor Pack had brought down a moose in its own territory, and the alpha male and another wolf were lying on the remains of the carcass, chewing the bones. Eight members of the East Pack were trotting along a snow-covered beach about a mile away when they abruptly changed direction and began crossing rough terrain in the direction of the moose carcass.
"You knew they were up to something," Vucetich recalls. "Then they rallied at an open pond, where they started to howl and sort of pump each other up."
Amazingly, the two Chippewa Harbor Pack wolves, who were well within earshot, took no notice of the commotion. Meanwhile, the East Pack wolves closed in on them and attacked. Both Chippewa Harbor Pack members tried to escape, but the East Pack chased down the alpha male and killed him on the spot.
"They ambushed him," Vucetich said. "He didn't have a chance."
Vucetich watched as the sole survivor fled to join the rest of the pack.
"For 15 or 20 minutes, he was interacting with his pack mates, trying to get them to get out of there," he said. "This was a subordinate trying to tell the alpha female that her mate was gone. Then, finally, they all got up and started to walk away." The pack retreated to the center of their territory, where they spent the next two days sleeping. "During the month that followed, Chippewa Harbor Pack lost about half of its territory to East Pack."
"Within a couple weeks, the alpha female was being courted," Peterson said. "She lost that alpha male just weeks before they would have mated, and a wolf can't lose a year of reproduction; that's totally unheard of."
This inter-pack warfare is not gratuitous, scientists say. It's a struggle for control of a diminishing food supply. "The wolves are short on moose, period, and they are really short on old moose," Peterson said. "Last winter, most moose they killed were 13 years or older, and now they are on the tag end of that baby boom generation, with nothing coming behind them."
"There are about 15 moose for every wolf now, and normally, there'd be about 40 or 50."
There's no reason to think that the moose are going to pop out of their population slump anytime soon, Peterson said. In addition to pressure from the wolves, their habitat has declined over the years, with old spruce and balsam fir slowly replacing the lusher birch and aspen forests.
Another sign of trouble is that moose are eating snow, a signal that they aren't getting enough food to provide them with the water they need. "We didn't see that 20 years ago," Peterson noted. "And they're also eating lichens. A 1,000 pound animal eating lichens! It's like eating dust."
The study is funded by the National Park Service, the National Science Foundation and Earthwatch.
Are they studying just to see what will happen?
Do they have an interest in protecting the moose population? If so, why don’t they take steps to reduce the current wolf population?
The DNR moves bears to different locations all the time… why not move one of the wolf packs back to the mainland?
Trap them ??
Classic case for a little trapping activity.
Properly carried out would work very well.
I think the reason for the study is to keep track of wolf/moose interactions without any interference from us humans other than capture and release.
spent 6 days on Isle Royale
an incredible place…we were there to backpack but did see some on the boat over from Grand Marais who had canoes. We went late in the season and the visitor center at Windigo had already closed. I would hasten any who love nature and stunning surrounds to visit this national park. Interestingly, it is one of the least visited NP’s along with the Dry Tortugas NP…if you dont like crowded NPs like Yellowstone consider Isle Royale.
It is the least visited, but for it’s size and the amount of hikers coming over on the ferry’s, it can get pretty darn crowded. That said, it is truly an incredible place.
As far as controlling the moose population, I remember a ranger telling us last year on the island that ticks can kill off as many moose as the wolves do in a given year. Not sure if that’s completely true, but I found that interesting.
last time I was there, they had’nt seen any sign of the one pack for quite awhile and had wories about the pack (couple of years ago) there is a very delicate balance out there. Sometimes it’s the moose and sometimes it’s the wolves they worry about. Just natures way. Never really in balance, unless looked at over a long period.
trapping or hunting only evens out the highs and lows…but on IR, they are using it as a place to study, not really change the balance in any way.
No clear answer
If humans wind up in the equasion the results may wind up worse for all creatures involved and yet,clearly, without human intervention the moose population will be erased and the wolf population along with them.
Has anyone thought about replanting the aspen and waters edge plants the moose seem to need?..Is there a ‘frontline’ tick medication for something as large as these creatures?
Finally, I’m sincerely hoping the wolves were indigenous to the area and not one of these “Oh Let’s Re-Introduce the Wolf” numbers.
Humans are only observers there.
We didn’t bring either species over to the island. They found their own way. It’s kind of a closed environment study of what happens when we don’t muck things up. Any intervention, be it medication, reintroduction of plant species, relocation of animals, etal. would taint the results. These are not some rare evolutionary off-shoot of mainland wolve or moose that are endanger of extinction; they’re still genetically the same. Our only role here is to observe what happens without us.
The wolves got there of their own accord. I heard that it was during an especially cold winter and that they crossed on the ice. I get the impression that the island seldom connects to the mainland via ice.
I’m not sure about both the moose and wolves being “erased”, though. A lot of things could happen (fires, for one), but as I understand it there is no directive in this case to “save” one animal or the other. That’s good really, as there are way too many places where we try to improve the situation and it backfires some how. Nature may be cruel at times, but it’s not “wrong”.
I remember seeing satelite photos of the Great Lakes last year or the year before and Superior was frozen solid. Historically it probably happens often,in the future who knows.
Likely a lot less ice.
Quick Google Search…
I started getting curious about this, and a quick search indicates that the lake was 90-percent ice-covered for a short time near the end of the winter in 2003, and that was considered to be highly unusual. It was almost totally frozen for a time in 1996, and the last time the lake actually froze-up completely was 1972. I’m sure it takes a lot less than total ice-up to connect Isle Royale to the mainland, however.
So soon the wolves will have to eat
people. An outcome devoutly to be hoped for.
It’s this flawed attitude
that will only result in the demise of the wolves. This is already happening in Michigan’s eastern upper peninsula as the grey wolf populations are on the rise and cattle populations are on the decline. Farmers are taking it upon themselves to control the problem locally.
Simply put, man is part of nature and to suggest that animals should just wipe us out or vice versa is extremist rhetoric. We should be looking for ways to coexist with animals by preserving their habitats and respecting their place in the world. That being said, I believe we have the same right.
By the way, this thought that Isle Royale’s wolf population is solely the pristine result of nature at work is also wrong; in an effort to alleviate inbreeding amongst the dwindling pack number, new animals were introduced by the park service in the 1980’s.
Hey, I agree that people should leave
wolves alone. I just think wolves, bears, giardia, etc., should cull people down to reasonable numbers.
It’s humorless attitudes like yours which allow anti- wilderness forces to prevail.