A practical guide to bird watching in Sonoma County, California

(Unless otherwise indicated, all phone numbers are in the 707 area code)


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)

Further reading:

Bolander and Parmeter, Birds of Sonoma County California, rev. ed., 2000, p. 37

Brinkley, National Wildlife Federation Field Guide to Birds of North America, 2007, p. 56

Burridge, ed., Sonoma County Breeding Bird Atlas, 1995, p. 43

Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 5th ed., 2006, p. 50

Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 6th ed., 2011, pp. 32, 51

Dunne, Pete Dunne’s Essential Field Guide Companion, 2006, pp. 66-67

Ehrlich, Dobkin, and Wheye, The Birder's Handbook, paperback edition, 1988, pp. 70, 107, 313

Fix and Bezener, Birds of Northern California, 2000, p. 102

Floyd, Smithsonian Field Guide to the Birds of North America, 2008, p. 56

Kaufman, Field Guide to Birds of North America, 2000, p. 40

Kaufman, Field Guide to Advanced Birding, 2011, pp. 100, 147, 153, 157

Lukas, Bay Area Birds: From Sonoma County to Monterey Bay, 2012, pp. 30-32

Parmeter and Wight, Birds of Sonoma County California, Update (2000-2010), 2012, p. 10

Peterson, Birds of Eastern and Central North America, 5th ed., 2002, p. 78

Peterson, Field Guide to Birds of Western North America, 4th ed., 2010, p. 38

Peterson, Western Birds, 3rd ed., 1990,  p. 58

Sibley, Field Guide to Birds of Western North America,1st ed., 2003, p. 93

Stokes, Stokes Field Guide to the Birds of North America, 1st ed., 2010, p. 54

Vuilleumier, American Museum of Natural History, Birds of North America: Western Region, 2011, p. 69

Voice: Cornell Lab of Ornithology: All About Birds--Ruddy Duck



© Colin Talcroft, 2009, 2010, 2011, 2012, 2013

Unless noted, all photos by the author. If you would like to use one of my images, please ask for permission for non-commercial use with proper credit or commercial use with proper compensation.


Female Ruddy Duck, Ellis Creek Water Treatment Facility, Petaluma, October 27, 2010.

Look for the heavy flat bill and pale cheek with a broad, dark line through it.

Ruddy Duck, male in breeding plumage, Lucchesi Park, Petaluma April 4, 2012

The black cap, white cheek, blue bill, ruddy back and sides and the stiff black tail identify this bird.

Male Ruddy Duck in winter plumage

North-end bodega Harbor, Bodega Bay, January 7, 2012.

The color is gone, but the goofy profile is unmistakable

Male Ruddy Duck in winter plumage, Lake Ralphine, Santa Rosa, January 10, 2012

For comparison: Female Bufflehead

Spring Lake, Santa Rosa, January 5, 2013

Ruddy Duck

Oxyura jamaicensis

1990-2013 Sonoma County data. Graph provided by eBird (www.ebird.org), generated August 4, 2013

EBird-reported occurrence in Sonoma County