LANSING, Mich. (AP) — State biologists say Michigan’s gray wolf population appears to be leveling off after several decades of steady growth.

The Department of Natural Resources says a census this winter produced an estimate of 662 wolves in the Upper Peninsula. That’s up slightly from 618 in the previous count two years ago.

The survey found 139 packs — 15 more than in 2016. The average pack size was down slightly, to fewer than five wolves.

The census was taken from December through April, before pups were born. That’s when the population is at its lowest point of the year.

Michigan wolves had all but disappeared before gaining legal protection in the 1970s.

Wildlife Division Chief Russ Mason says they’re now thriving. Recent surveys suggest the minimum population may be stabilizing at 600 to 700.