With 220 records, the beaver has the densest cluster of reports of any species on this page, though NatureServe still ranks it vulnerable in the District. Rock Creek Park alone accounts for 19 of them, while Kenilworth Park and Aquatic Gardens’ shallow ponds, Theodore Roosevelt Island’s marshy edges, and the tidal reaches of the Anacostia and Potomac Rivers round out the rest of DC’s records.
Beavers reshape the water they live in rather than just occupying it. Where a stream runs shallow, a colony dams it with cut branches, mud, and stones until the pond behind it is deep enough to hide the underwater entrance to their lodge and float a winter cache of branches. Along DC’s deeper tidal rivers, where the water already runs high, beavers are more likely to skip the dam and dig a burrow straight into the bank instead.
Records peak in April and May, when beavers are most active repairing winter damage to dams and lodges, and yearlings disperse to look for territory of their own.
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