A practical guide to bird watching in Sonoma County, California
(Unless otherwise indicated, all phone numbers are in the 707 area code)
Present in small numbers throughout the year, but somewhat more common in the winter months. Nests in the southern part of the county, near San Pablo Bay. Usually seen in pairs or small flocks of its own kind, but also mixes with other dabbling ducks. Prefers quiet ponds and sloughs with muddy bottoms and with the cover of overhanging vegetation, but also found on marshes, ponds, small lakes, lagoons, and in tidal channels.
The Gadwall is perhaps more common than it seems. Even the male is fairly plain (above) and its rather drab coloration may cause it to be overlooked or dismissed by casual birders as yet another nondescript female duck. In reality, the Gadwall is very handsome when seen up close or through good binoculars that show the subtleties of its plumage. The general impression the male gives is of a uniform greyish brown, but a good view reveals a finely patterned head, neck, breast, and sides with reticulations that suggest fine tweed. The scapulars, seemingly draped over the back, are a warmer brown on the back shading into pale grey toward the rear of the bird. The bill is black, the eye dark. The crown is usually a shade darker than the rest of the head, and there is a suggestion of an eyeline--usually darker and broader in front of the eye than behind. The shape of the head is fairly distinctive--proportionately small, but with a steep slope in front and back, which makes it look like a rounded square. The stern of the bird is a sharply contrasting black. The belly, when exposed, is pale. The feet are yellowish-orange. When swimming, the white speculum may be nearly hidden, as in the photo above, or it may show as a white lateral bar toward the rear of the bird. There is a patch of brown at the upper edge of the white speculum, which may be visible in flight at close range or when the bird is preening or stretching its wings.
The female resembles a female mallard but with a less distinct eyeline and a less brightly colored bill. The bill is usually dark but edged with varying degrees of orange (photo below). The speculum is white, and--as in the male--it may be completely hidden or it may show as a white bar toward the rear of the bird (a female Mallard will have a deep purplish blue speculum). The female Gadwall's head has the same rounded square look of the male's head.
The challenges of female duck identification (includes a quiz)
Further reading:
Bolander and Parmeter, Birds of Sonoma County California, rev. ed., 2000, p. 29
Brinkley, National Wildlife Federation Field Guide to Birds of North America, 2007, p. 42
Burridge, ed., Sonoma County Breeding Bird Atlas, 1995, p. 41
Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 5th ed., 2006, p. 32, 53
Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 6th ed., 2011, p. 28, 50
Dunne, Pete Dunne’s Essential Field Guide Companion, 2006, pp. 33-34
Ehrlich, Dobkin, and Wheye, The Birder's Handbook, paperback edition, 1988, p. 62
Fix and Bezener, Birds of Northern California, 2000, p. 77
Floyd, Smithsonian Field Guide to the Birds of North America, 2008, p. 40
Kaufman, Field Guide to Birds of North America, 2000, p. 28
Kaufman, Field Guide to Advanced Birding, 2011, pp. 149, 152, 153
Lukas, Bay Area Birds: From Sonoma County to Monterey Bay, 2012, pp. 6-7
Parmeter and Wight, Birds of Sonoma County California, Update (2000-2010), 2012, p. 5
Peterson, Birds of Eastern and Central North America, 5th ed., 2002, p. 66, 84
Peterson, Field Guide to Birds of Western North America, 4th ed., 2010, p. 26, 42
Peterson, Western Birds, 3rd ed., 1990, p. 44
Sibley, Field Guide to Birds of Western North America,1st ed., 2003, p. 76
Stokes, Stokes Field Guide to the Birds of North America, 1st ed., 2010, p. 19
Vuilleumier, American Museum of Natural History, Birds of North America: Western Region, 2011, p. 46
Voice: Cornell Lab of Ornithology: All About Birds--Gadwall
© 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.
Male Gadwall, Ellis Creek Water Treatment Facility, Petaluma, April 7, 2012
Female Gadwall, Lake Ralphine, Santa Rosa, March 12, 2012
Gadwall pair, Lake Ralphine, Santa Rosa, March 12, 2012
Gadwall
Anas strepera
1990-2013 Sonoma County data. Graph provided by eBird (www.ebird.org), generated July 2, 2013
EBird reported occurrence in Sonoma County
