Officials plan to relocate several gray wolves from the Canadian province of Ontario to Isle Royale National Park this winter.
It's the next step in rebuilding the depleted wolf population at the Lake Superior park.
Only two remained until crews took four more wolves to the island from Minnesota this fall. Park spokeswoman Liz Valencia says the goal is to get four from Ontario in coming months.
Plans call for transporting 20-30 mainland wolves to Isle Royale in the next few years.
The predators are considered essential for keeping the park's moose from overpopulating and eating too much greenery.
The wolf population has dropped sharply in recent years.
Researchers with the National Park Service and other agencies will monitor fluctuations in the moose and wolf populations, genetics, vegetation and other factors to evaluate whether the mission has succeeded.