The reasons cited in a story today on Michigan Radio’s Environment Report , include disease, food shortage, and genetics among other things. Wolves originally came to the island, now a national park, in the 1940’s. They crossed over on the ice making a 25 mile trip from the mainland. Those ice bridges don’t form nearly as often these days. That leaves the population genetically isolated and inbred.
After more than 25 years in the outdoor writing business, you would think I'd know better.