Lake Superior’s wolves thriving as packs prey on moose, researchers say | US news
Wolves on a remote island in Lake Superior appear to be thriving, but they’re making deep dents in the deer population they rely on as a leading food source, according to a report released Monday.
Isle Royale is a 134,000-acre (54,200 ha) national park in the western part of Lake Superior between Grand Marais, Minnesota, and Thunder Bay, Canada. The island is a natural laboratory that offers scientists a rare opportunity to observe wolves and moose largely free from human influence.
Researchers have been conducting wolf and deer population studies on the island since 1958. These surveys were an annual winter event when the trackless island was closed to visitors, but researchers have run into obstacles in recent years.
The pandemic in 2021 forced scientists to cancel research for the first time. The National Park Service ordered researchers to evacuate the island during the 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 runways, forcing them to land on icy Lake Superior. Things didn’t go so well last year when researchers had to abandon their efforts due to a last-minute medical issue for their pilot.
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 findings from the study led them to estimate the wolf population on the island at 37 animals. Data collected before the evacuation in the 2024 survey showed the population at 30.
The 2026 projections are the highest since the late 1970s and represent a marked improvement since the population fell below just two wolves a decade ago. Researchers believe that inbreeding leads to reduced survival rates in offspring.
But the island’s deer population is decreasing significantly. This year’s survey revealed moose numbers at 524, down 75% from the peak number of 2,000 in 2019. Wolves likely killed nearly a quarter of the moose population last year, scientists estimate. For the first time in almost 70 years, researchers did not encounter moose calves during the winter survey.
Sarah Hoy, a Michigan Tech researcher who specializes in predator-prey interactions and one of the study’s co-leaders, said the scientists had to brave wind chills as low as -50F (-45.5C) and it was difficult to stay warm with wood stoves in their cabins.
But clear skies facilitated extraordinary observations. He said scientists detected wolves on all but one research flight. He said one of the highlights was watching a pack get snuggled together on ice on Valentine’s Day.
“It is always a great privilege to see wolves interacting, witnessing courtship behavior, cubs playfully tugging on each other’s tails, or a pack working together to take down a moose,” he said.
Scientists plan to conduct summer research on the island, investigating how thriving wolf packs can maintain balance with the rest of the ecosystem.
