Wolves on a remote island in Lake Superior They appear to be thriving, but they are making deep dents in the moose populations that depend on them as their main food source, according to a report released Monday.
Isle Royale is a 134,000-acre (54,200 ha) national park on the westernmost point of Lake Superior between Grand Marais, Minnesota and Thunder Bay, Canada. The island is a natural laboratory, providing scientists with a rare opportunity to observe wolves and moose largely free of human influence.
Researchers conducted Population surveys of wolves and moose on the island since 1958. The surveys were an annual winter event when the roadless island is closed to visitors, but The researchers faced obstacles In recent years.
The pandemic in 2021 forced scientists to cancel the survey for the first time. The National Park Service ordered researchers to evacuate the island during the 2024 winter survey after weeks of unseasonably warm weather left the ice surrounding the island unsafe for ski planes to land. Researchers rely on planes to make it easier to track wildlife, but the island has no runway, forcing them to land on icy Lake Superior. Things didn’t go any better last year when researchers had to cancel the effort after their pilot had a last-minute medical problem.
But this year, a team of researchers led by scientists from Michigan Tech University was able to conduct a survey from January 22 to March 3. The survey results led them to estimate the number of wolves on the island at 37 animals. Data collected by scientists before their evacuation in 2024 showed the population to be 30 people.
The 2026 estimate is the highest since the late 1970s and represents a marked improvement since the population dwindled to just two wolves a decade ago. Researchers believe that inbreeding resulted in lower survival rates for the pups.
However, moose numbers on the island are declining dramatically. This year’s survey put the moose population at 524 animals, down 75% from a high of 2,000 in 2019. Wolves likely killed nearly a quarter of the moose population over the past year, scientists estimate. For the first time in nearly 70 years, researchers did not observe any moose calves during the winter survey.
Scientists had to contend with wind chills that dropped to 50 degrees Fahrenheit (minus 45.5 degrees Celsius) and it was difficult to keep warm with wood stoves in their cabins, said Sarah Hoy, a Michigan technology researcher who specializes in predator-prey interactions and one of the leaders involved in the survey.
But clear skies facilitated exceptional observations. She said scientists spotted wolves on all but one survey trip. One highlight, she said, was watching a group of animals snuggle together on the ice on Valentine’s Day.
“It’s always a treat to see wolves interacting, witness courtship behavior, pups tugging each other’s tails, or a pack working together to take down a moose,” she said.
Scientists plan to conduct summer research on the island with a focus on how to keep thriving wolf packs in balance with the rest of the ecosystem.