Why ravens are disappearing from this Michigan island | MLive.com

ISLE ROYALE, MI – Raven numbers are dropping on Michigan’s remote Isle Royale, and the reason has a lot to do with wolves.

National Park staff who oversee the island archipelago sitting 60 miles from the Upper Peninsula mainland say the clever birds’ decline in numbers is linked to the steep drop in the island’s wolves in recent years.

Ravens typically eat a good portion of what the wolves kill for food. And fewer wolves mean fewer kills and fewer chances for ravens to swoop in and enjoy the free buffet.

“As wolves scour for their next meal, they are often accompanied by a group of ravens flying above,” park staff wrote on Isle Royale’s Facebook page. “Once wolves have caught their dinner, ravens will be right next to them, devouring up to one third of the wolves’ kill. The declining wolf population on the island means less moose carcasses for these scavengers, and has caused a decrease in ravens as well.”

In the last several years, Isle Royale’s once-robust wolf packs have dwindled to just two of the predators – an aging pair so deeply related that scientists who have studied the population say they have no chance of producing viable offspring.

This spring, the National Park Service announced plans to replenish the island’s wolf packs by catching wild wolves in the Great Lakes area and bringing them to Isle Royale, perhaps as early as this fall.

Once the wolves return in numbers, will the ravens?