A stretch of unusually warm weather has forced federal officials to temporarily halt researchers’ annual count of wolves and moose in remote Isle Royale national park for the first time in more than six decades.
Isle Royale is a 134,000-acre island situated in far western Lake Superior between Grand Marias, Minnesota, and Thunder Bay, Canada. The Michigan park is a wildlife biologist’s dream – it offers a rare opportunity to observe wolves and moose without human influence.
Researchers have conducted an annual survey of the park’s wolf and moose population since 1958, every year except 2021, when the Covid-19 pandemic forced its cancelation.
Scientists from Michigan Tech University returned to the island on 19 January, planning to survey the wolf and moose populations from the air through March, said Sarah Hoy, a Michigan Tech research assistant professor who leads the project alongside John Vucetich, a Michigan Tech forestry professor, and Rolf Peterson, a retired Michigan Tech ecology professor.
Hoy said that the National Park Service suspended the survey on Tuesday and ordered everyone off the island. She said warm temperatures have left the ice around the island unsafe for the scientists’ ski-planes to land.
“The ice on the harbor was starting to deteriorate, I guess,” Hoy said. “We lost some ice depth and a few holes and cracks were starting to appear … Everybody had to leave. So the island’s now only occupied by wolves and moose and a bunch of critters. We’re incredibly disappointed that we’re not able to continue our work.”
Temperatures in the region have hovered above freezing since 24 January, about 20 degrees above average, according to the National Weather Service. The mercury hit 47F (8C) in the area on Wednesday.
Hoy said helicopters were not an option because they are expensive to rent and so loud they would disturb the wildlife. The team may return to the park if temperatures drop and the ice firms up enough to support ski-planes again. It’s too far to fly from the mainland to the island, complete survey circles and fly back, she said.
Otherwise, the team may return to the park in spring by boat – but winter snow and bare branches makes tracking the animals much easier.
The scientists’ 2022-23 survey put the number of wolves on the island at 31, up from 28 wolves the prior year, and the number of moose at 967, down 28% from 1,346.
The team attributed the decline to lower survival rates for calves, starvation and wolf predation. The scientists calculated a rate of an estimated 0.52 moose killed for each wolf every month last year.
Extreme weather across many parts of the US this winter has seen wild fluctuations amid the worsening climate crisis. Freezing temperatures have been prolonged in parts of the deep south and close to the Mexico border, while unseasonably balmy warmth has bathed parts of the far north, with a lack of snow in many ski areas and biblical deluges out west.
The Associated Press contributed reporting
