Wisconsin’s occurrence databases hold 790 beaver records, among the higher counts of any mapped mammal in the state, with reports climbing sharply each spring.
Building water back into the sand country
Necedah National Wildlife Refuge sits in Wisconsin’s central sand plains, a stretch of pine and oak flats and restored wetland where old drainage ditches once dried out a much larger marsh. Beavers there dam those same channels and raise water levels across patches of the refuge, working in the opposite direction of the ditches dug decades ago. It’s one of the clearest examples in Wisconsin of a beaver’s engineering reshaping ground people also manage by hand.
Backwater dens along the Mississippi
Trempealeau National Wildlife Refuge sits inside Wisconsin’s Driftless Area, where wooded bluffs drop straight to the Mississippi River’s backwater sloughs and oxbow lakes. Beavers here den in bank burrows and stick lodges built from silver maple and cottonwood cut along the bottomland forest, storing branches underwater near the lodge to feed on through the cold months.
A record climb every spring
Wisconsin’s beaver reports rise sharply in April and May, when ice-out reopens the state’s rivers and lakes and beavers become easier to spot swimming the banks and cutting fresh growth after months under the ice.
Status in Wisconsin
NatureServe ranks the beaver S5, secure, in Wisconsin, and it’s native across the state. It’s Wisconsin’s most widespread aquatic engineer, found wherever slow water and hardwood cover meet, from the Mississippi’s backwaters to the Northwoods’ glacial lakes.
Full species profile
