TRAVERSE CITY (WWJ/AP) – The gray wolf population in Michigan’s Upper Peninsula appears to have declined slightly in recent years, but state biologists say it’s stable and healthy.

The Department of Natural Resources estimates the minimum number of wolves at 618, based on survey results announced Thursday. That’s down from previous estimates of 636 wolves two years ago and 687 in 2011.

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But wildlife management specialist Kevin Swanson says when statistical error margins are factored in, the population likely has changed little if at all.

The survey is based on track counts and aerial observation of wolves wearing radio tracing collars.

Swanson said, based on the 2016 minimum population estimate, it is clear that wolf numbers in Michigan are viable, stable and have experienced no significant change since 2014.

“Currently, deer numbers in the U.P. are at lows not seen in decades and we wondered if there would be a decline in wolf numbers as a result of this reduction in their primary source of prey,” Swanson said. “We also did not observe a significant difference in the number and average size of wolf packs as compared to 2014.”

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Wolves had all but disappeared from Michigan by the 1970s but rebounded after getting federal protection. Over the past few years, Michigan’s minimum population estimate has hovered between 600 and 700 wolves.

In January 2012, citing wolf recovery in the region, the U.S. Fish and Wildlife Service took gray wolves off the federal endangered species list in Michigan, which allowed for citizens to kill a limited number of wolves each year.

However, Michigan’s law on hunting to control the wolf population was suspended in December 2014, after a ruling from the U.S. District Court in Washington, D.C. In a lawsuit challenging the endangered species delisting, the court ruled in favor of the Humane Society of the United States, ordering wolves returned to federal protection. Wolves have since remained classified as an endangered species in Michigan.

Because of the federal endangered species status, Michigan citizens may only legally kill a wolf in defense of human life.

After the court’s finding, Michigan, Wisconsin, some private groups and the U.S. Fish and Wildlife Service appealed the decision, filing their initial legal briefs in the case late last year. The court has not yet released a timeline of its deliberations.

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