Beavers are Michigan’s biggest waterworks engineers, and the state’s 1,629 mapped records trace the rivers and wetlands of the Upper Peninsula, most heavily around Seney National Wildlife Refuge and Pictured Rocks National Lakeshore, down through the farmland-and-woodlot country of southern Lower Michigan. Records span nearly every county with year-round water, a real recovery from a species trapped hard for its fur through the 1800s.
A dam-building tenant at Seney
Seney’s namesake refuge is built on the old Great Manistique Swamp and is threaded with man-made pools and dikes meant to hold water for waterfowl. Beavers add their own dams on top of that system, and refuge crews sometimes have to breach a beaver dam that’s backing water up somewhere it isn’t wanted, a small tug-of-war between two different kinds of engineering on the same stretch of wetland.
What the spring peak in records shows
Beavers eat bark, twigs, and water plants, and they cache branches near the lodge to get through the coldest months. Records climb sharply in April and May, right around ice-out, when beavers are most active repairing winter-damaged dams and young animals start dispersing to find their own stretch of stream, both of which put more beavers in view of anyone out along Michigan’s rivers.
Status in Michigan
NatureServe ranks the beaver S5, secure, and Michigan lists it as native. After being trapped out of much of the state, beavers have recolonized nearly every watershed with year-round water, from Upper Peninsula boreal streams to the drainage ditches of southern farm country.
Full species profile
