A practical guide to bird watching in Sonoma County, California

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


Common in Sonoma County during spring and autumn migration and over the summer, but little seen here in the winter months. Favors fairly dense woods near water (likes willows and alders), bogs and thickets near water, wooded edge environments near the coast and inland, and occasionally coniferous forest. Flits rapidly among the branches of trees and bushes gleaning insects, making it hard to get a good look at this bird, which never seems to sit still for more than an instant. Also hover-gleans and flycatches. In the spring, presence often recognized by song before the bird is seen (link below). Known to nest in appropriate habitat in most of Sonoma County except the southern extreme, near the Petaluma-area wetlands and San Pablo Bay. Named for pioneer ornithologist Alexander Wilson (active early 19th century). The American Ornithological Union moved this species from the genus Wilsonia to the genus Cardellina in July 2011. Older sources will call this bird Wilsonia pusilla

Wilson's Warbler is one of our more distinctive warblers. Smaller than many warblers but with a proportionately long tail. Males are easily recognized by the black cap and beady black eyes that contrast sharply with the otherwise mostly yellow face and underparts. Yellow-olive back, wings, and tail. No wing bars or sometimes just a hint of wing bars. Comparatively thin, orange-tinged legs. Yellow is brightest on the face, especially above and in front of the eye. Many field guides show a variable olive auricular patch. Pacific Coast birds of the subspecies C. pusilla chryseola are the yellowest of the three main subspecies recognized and have the palest, least marked faces (in other words, they are least likely to have the olive patch) but show a slight orange tinge at the forehead. The bird in the photo above is chryseola. Females are similar to males but somewhat drabber in color and with a less developed black cap (at some angles, may appear almost capless). Female cap may be more olive than black and may be lacking entirely in immature females. Also reduced in first-fall males.

Wilson's Warbler may be confused with Yellow Warbler (Setophaga petechia) in that bird's duller plumages, but Yellow Warbler never has a black or dark cap and Yellow Warbler is yellow where Wilson's Warbler is yellow-olive.  

Selected county sightings: Gracianna Winery, Westside Rd. (Jan 21, 2014, an unusual winter sighting, Colin Talcroft); Spring Lake (April 14, 2012, Colin Talcroft); Owl Canyon, Bodega Bay (April 7, 2012, Daniel Edelstein); Owl Canyon, Bodega Bay (October 26, 2011, Scott Carey); North End Bodega Harbor (October 17, 2011, Ruth Rudesill)

English synonyms: Blackcap, Black-cap Green Warbler, Black-capped Warbler, Green Black-capped Warbler, Pileolated Warbler, Wilson's Flycatcher

Wilson’s Warbler in other languages--German: Mönchswaldsänger, Mönchs-Waldsänger; Spanish: Bijirita de Wilson, Chipe Corona Negra, Chipe Coroninegro, Chipe de Coronilla Negra, Chipe de Wilson, Chipe pelucillo, Ciguíta de Wilson, Reinita de Wilson, Reinita Gorrinegra; French: Fauvette à calotte noire, Paruline à calotte noire, Sylvette à calotte noire; Dutch: Wilsons Zanger, Wilson-zanger; Russian: Вильсония малая, Вильсония-крошка, Малая вильсония; Chinese: 黑头威森莺; Japanese: ウィルソンアメリカムシクイ (uiruson amerikamushikui)

(Language information from Avibase, Birds of Europe (Mullarney et al, Princeton Field Guide Series), and Birds of Asia (Mark Brazil, Princeton Field Guide Series).

Further reading:

Bolander and Parmeter, Birds of Sonoma County California, rev. ed., 2000, p. 110

Brinkley, National Wildlife Federation Field Guide to Birds of North America, 2007, p. 368

Burridge, ed., Sonoma County Breeding Bird Atlas, 1995, p. 152

Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 5th ed., 2006, p. 392

Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 6th ed., 2011, p. 450

Dunn and Garrett, Warblers: Peterson Field Guides, 1st ed., 1997, pp. 549-559, pl. 26 (spanning pp. 94-95)

Dunne, Pete Dunne’s Essential Field Guide Companion, 2006, pp. 573-574

Ehrlich, Dobkin, and Wheye, The Birder's Handbook, paperback edition, 1988, p. 538

Fix and Bezener, Birds of Northern California, 2000, p. 320

Floyd, Smithsonian Field Guide to the Birds of North America, 2008, p. 405

Kaufman, Field Guide to Birds of North America, 2000, p. 304

Kaufman, Advanced Birding, 1990, pp. 229-232 (general notes on warbler ID), p. 229

Kaufman, Field Guide to Advanced Birding, 2011, pp. 390-411 (general notes on warbler ID), pp. 394, 397, 403, 411

Lukas, Bay Area Birds: From Sonoma County to Monterey Bay, 2012, p. 244-245

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

Peterson, Birds of Eastern and Central North America, 5th ed., 2002, p. 272

Peterson, Field Guide to Birds of Western North America, 4th ed., 2010, p. 320

Peterson, Western Birds, 3rd ed., 1990,  p. 302

Sibley, Field Guide to Birds of Western North America,1st ed., 2003, p. 387

Stephenson and Whittle, The Warbler Guide, 2013, pp. 452-459

Stokes, Stokes Field Guide to the Birds of North America, 1st ed., 2010, p. 636

Stokes, Stokes Field Guide to Warblers, 2004, pp. 52-53

Vuilleumier, American Museum of Natural History, Birds of North America: Western Region, 2011, p. 369

Voice: Cornell Lab of Ornithology: All About Birds--Wilson's Warbler



© Colin Talcroft, 2009-2018

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.


Wilson's Warbler, Hole in the Head, Bodega Bay, June 26, 2013

Wilson's Warbler

Cardellina pusilla

1990-2013 Sonoma County data. Graph provided by eBird (www.ebird.org), generated May 30, 2013

EBird reported  occurrence in Sonoma County

Wilson’s Warbler, Spring Lake Park, Santa Rosa, June 14, 2018