Researchers say Lake Superior island’s wolves are thriving as packs prey on moose

Wolves on a remote Lake Superior island appear to be thriving, but they are significantly reducing the moose population they rely on as their primary food source, according to a report released Monday.

Isle Royale is a 134,000-acre (54,200-hectare) national park located on the far western edge of Lake Superior, between Grand Marais, Minnesota, and Thunder Bay, Canada. The island is a natural laboratory offering scientists a rare opportunity to observe wolves and elk largely free of human influence.

Researchers have been conducting surveys of wolf and moose populations on the island since 1958. These surveys were an annual winter event when the roadless island was closed to visitors, but researchers have faced obstacles in recent years.

The 2021 pandemic forced scientists to cancel the investigation for the first time. The National Park Service ordered researchers to evacuate the island during their 2024 winter survey after weeks of unusually warm weather made the ice surrounding the island unsafe for ski plane landings. Researchers rely on planes to more easily track wildlife, but the island has no airstrip, forcing them to land on ice-covered Lake Superior. Things didn’t go much better last year when the researchers were forced to abandon their efforts after their pilot suffered a last-minute medical issue.

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 island’s wolf population at 37 animals. Data collected by scientists before their evacuation during the 2024 survey showed a population of 30 inhabitants.

Estimates for 2026 are the highest since the late 1970s and represent a marked improvement since the population fell to just two wolves a decade ago. Researchers believe that inbreeding has led to lower puppy survival rates.

However, the island’s moose population is experiencing a dramatic decline. This year’s survey estimates the population at 524 moose, down 75% from a high of 2,000 in 2019. Wolves likely killed nearly a quarter of the moose population in the last year, scientists estimate. For the first time in nearly 70 years, researchers did not observe any moose calves during the winter inventory.

Sarah Hoy, a researcher at Michigan Tech who specializes in predator-prey interactions and one of the survey’s co-leaders, said the scientists had to brave wind chills that plunged to minus 50 degrees Fahrenheit (minus 45.5 Celsius) and it was difficult to stay warm with the wood stoves in their cabins.

But clear skies facilitated exceptional observations. Scientists spotted wolves on all but one survey flight, she said. One of the highlights was seeing a pack huddled together on the ice on Valentine’s Day, she said.

“It’s always such a privilege to see wolves interact, witness courtship behaviors, pups pulling 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 to determine how thriving wolf packs can maintain balance with the rest of the ecosystem.