Ruddy Duck

The male Ruddy Duck is striking in breeding plumage--when he's at his ruddiest. The black cap; white face; bright blue, flat, rather heavy bill; and stiff, wiry tail are distinctive. Common in Sonoma County (in non-breeding plumage) during the winter months. Ruddy Ducks usually start arriving in the middle of September to early October. Numbers thin rapidly from around the middle of the following May. A small number may stay over the summer, but generally not much seen here in June, July, and August. There is, however, a small breeding population in the county. Breeding records exist for Annadel State Park and the southern extreme of the county, near San Pablo Bay, according to the Breeding Bird Atlas. May be found in salt water (where it favors protected bays and estuaries) but also in brackish water and freshwater ponds. Not uncommon inland on farm ponds and water treatment ponds. Tends to stay in loose flocks. Often content to spend longs periods simply floating with a tucked head. Almost never seen on land--Ruddy Ducks are said to be barely capable of walking. Noted as a brood parasite (targeting Redheads, and Canvasbacks, especially, but also grebes, and rails, although Ruddy Ducks apparently more often slip eggs into the nests of fellow Ruddy Ducks than into the nests of other species, according to The Birder's Handbook).

The male bird in breeding plumage is hard to mistake (photo below), but often Ruddy Duck can be identified simply by silhouette and at a great distance; the short neck, large bill, and stiff, ragged tail (often held upright) are the only clues required. In silhouette, the tail may suggest Northern Pintail (Anas acuta), but Ruddy Duck and Pintail are otherwise utterly different; Northern Pintail is notable for its long, elegant neck, Ruddy Duck for its squat, short-necked look. In non-breeding plumage, Ruddy Duck males are brownish at the breast, pale along the flanks, and brownish-grey on top. They retain the dark cap and the white cheek of breeding plumage, but the bill loses most of its striking blue. Note that the face and head may become stained from mucking about looking for food (like the bird in the photo above). Female Ruddy Ducks share the silhouette of the male, the dark cap, and a pale (if not white) cheek but have a dark, diffuse stripe across the side of the face (photo below). Immature birds resemble females. Females are often mistaken for female Buffleheads, and vice versa, but the shapes of the two birds are quite different, and note particularly the small size of the Bufflehead's bill and that the female Bufflehead has a white patch on a dark cheek, whereas the cheek of the female Ruddy Duck is pale marked with a dark stripe (photos below). In the field and at a distance these differences may appear far less obvious than the photos suggest.

The challenges of female duck identification (includes a quiz)