The Wolves and Moose of Isle Royale annual winter study has finished, and the preliminary results have been published in the press. It was a good winter for wolves and moose, according to the Associated Press story, which I have attached as a comment to this post. Moose were up substantially, by about 40%. Wolves were up slightly. There are very few old moose left on the island nowadays, which means that the wolf population should decline -- it perhaps should have declined this past winter. But not so. You can read the blog of the research study at isleroyalewolf.org. The magazine cover on display here shows that Lake Superior featured the 50th anniversary of the study in a recent issue. There have been a number of other magazine articles published about the anniversary lately, many of which can be found on the web by using a search engine.
Encouraging Results from the Annual Study of Moose and Wolves
The Wolves and Moose of Isle Royale annual winter study has finished, and the preliminary results have been published in the press. It was a good winter for wolves and moose, according to the Associated Press story, which I have attached as a comment to this post. Moose were up substantially, by about 40%. Wolves were up slightly. There are very few old moose left on the island nowadays, which means that the wolf population should decline -- it perhaps should have declined this past winter. But not so. You can read the blog of the research study at isleroyalewolf.org. The magazine cover on display here shows that Lake Superior featured the 50th anniversary of the study in a recent issue. There have been a number of other magazine articles published about the anniversary lately, many of which can be found on the web by using a search engine.
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April 6, 2008. (AP) A 50-year-old research project on predator/prey relationships has found gains in the moose and wolf populations on Lake Superior's Isle Royale in the past year.
The study, which is considered the longest-running study of its kind in the world, found that the number of wolves on the lake's biggest island have increased from 21 in 2007 to 23 in 2008 and grew from three to four packs.
An estimated 385 moose were found on the island last year. This year's count was estimated at 650, according to the study.
Moose have been on the island located 15 miles off Grand Portage since about 1900. Their population peaked in 1995 at 2,445, and last year's 385 represent the lowest count.
Wolves arrived on the island in 1949 after crossing winter ice. The lowest count was 11 in 1993, and the highest was 50 in 1980.
Moose are more difficult to count than wolves, and researchers said difficult conditions last year may have resulted in undercounting.
The current wolf population is about normal, but the moose population is well below average, researchers said. They noted that the island now has very few old moose, which often become wolves' target.
The wolves might have to work harder to get a meal, which could make their numbers decrease in the next count, said John Vucetich, co-leader of the Isle Royale study and a professor of forestry at Michigan Technological University. Wolf numbers crashed from 30 to 21 from 2006 to 2007.
"We were a bit surprised that wolf numbers went up even by two. We expected them to slide again this year because there are so few moose on the island now," Vucetich said. "The creation of a fourth pack also is very unusual. It's only the fourth time in 50 years that's happened."
Vucetich said researchers were also surprised that the moose population perhaps increased this year. Seven of the past 10 summers have been among the warmest in 50 years. When temperatures are above 55 degrees, moose begin to feel heat stress, Vucetich said.
On hot summer days, moose sometimes stop eating, which reduces the amount of fat they have on their bodies to survive winter, he said.
Ticks have also caused stress to the moose, which try to rub the ticks off. Researchers said there's a link between the stress and moose calf numbers. Last year's calf numbers declined from an average of 15 percent of the population to just 5 percent. This year's calves will be counted later this spring.
With more warm summers, the Isle Royale moose population could see a long-term decline, Vucetich said. That would mean a decline in wolves.
"If moose drop much more, it's the wolves that would likely go extinct first," Vucetich said. "Once that happens, the few remaining moose may actually do pretty well."
Besides counting animals, the study looks at the effects of climate and weather, parasites, disease, forest changes and time. Researchers also look at interaction with foxes and ravens.
"Isle Royale is a fairly simple system, yet it is still so complicated that it surprises us almost every year," said retired Michigan Tech professor Rolf Peterson, who started working on the study in 1970. "People want to predict the future with wildlife and (nature) and that's just laughable. We can't predict it at all."
Vucetich and Adrian Wydeven, a wolf biologist for the Wisconsin Department of Natural Resources, said they hope the study will continue another half-century.
"The real value of their research has been showing how much change there is over the years," Wydeven said. "If they would have ended that research at the end of any of (the) decades, they would have had vastly different conclusions."
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