HOUGHTON, Mich. (AP) — Officials at Isle Royale National Park say they've wrapped up the first phase of a multi-year effort to rebuild the gray wolf population.

Three females and one male were trapped on the Minnesota mainland in recent weeks and flown to the Lake Superior park. A fifth wolf died during transit.

Two other wolves were already at the park — the last survivors of a population that had nearly disappeared because of inbreeding and other factors.

Officials had hoped to bring some Michigan wolves to the park this year. But superintendent Phyllis Green says bad weather has hampered trapping. She says the next phase of the project could include relocating some Canadian wolves this winter.

Up to 30 wolves will be taken to the park in the next three to five years.