American Beaver turns up across Delaware in two very different kinds of water: the diked freshwater impoundments of Bombay Hook National Wildlife Refuge on the coastal plain, and the rockier Piedmont streams of Brandywine Creek and White Clay Creek near Wilmington. With 202 combined iNaturalist and GBIF records, it’s among the more frequently recorded mammals in the state’s occurrence data, though that tally tracks who’s been looking, not how many beavers are actually out there.
Two kinds of Delaware water, one habit
A beaver needs permanent water deep enough to hide its lodge entrance, plus woody plants close to the bank, and Delaware offers that in two distinct settings. In the Piedmont sliver around Wilmington, Brandywine Creek and White Clay Creek run faster and rockier than most of the state, lined with the same hardwood banks beavers key on elsewhere in their range. Further south and east, the land flattens into the Atlantic Coastal Plain, where Bombay Hook’s managed freshwater impoundments, built for waterfowl, work just as well for a species that dams anything slow enough to pond up.
A vegetarian that never touches Delaware Bay
Despite living within sight of the refuge’s tidal marsh, a beaver never eats anything from that brackish water. It sticks to bark, twigs, and aquatic vegetation, and the sycamore, silver maple, and willow lining Delaware’s Piedmont streams supply much of that diet. Records here show up in every month, with the heaviest reporting from March into May, when ice-free water and active dam repair make beaver sign easiest to spot.
Status in Delaware
NatureServe ranks the American Beaver S3, vulnerable, in Delaware, and the species is native to the state. USGS NAS doesn’t list it as nonindigenous here, so its presence reflects the state’s original range rather than an introduction.
Full species profile
