A practical guide to bird watching in Sonoma County, California

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


Our most common swallow. Present in small numbers throughout the year, but most common during the summer months and during spring and autumn migration. Most common between April and July, although numbers begin to pick up as early as late February and a fair number of birds will linger into early October. Tends to forage at higher elevations than most other local swallows--as high as 2,000ft, according to Fix and Bezener. Less closely attached to environments with water than most other swallows. Favors edge habitats, openings in wooded areas, and open oak woodland often at higher elevations. Breeds widely throughout the county, virtually in all areas except those in the extreme south that are mostly devoid of trees. Uses tree cavities and cliff crevices. Winters as far south as Costa Rica.

Perhaps the most beautiful of the common swallows--although it can be hard to see the Violet-green Swallow’s striking colors. Like all swallows, usually glimpsed on the fly, but worth following with binoculars; the reward when the light and angle of view is right is a flash of purple and green like no other bird we regularly see. Richly colored upperparts contrast with a pure white underside and this bird has more white on the face than any other local swallow. It has the brightest, cleanest look among them. The contrasting light and dark and the bird’s slightly plump profile always remind me of a killer whale. Males have a mossy green cap and nape. Sea green on the back. Violet at the rump and with blue-violet tinges at the “shoulders.” Wings and the rather short tail are a bluish charcoal grey to black. Uniformly white underneath. White on cheek with white extending behind and above the eye. White also at the sides of the rump. The white rump patches (sometimes referred to as pom-poms) are roundish and almost meet at the center of the rump. Females duller and with more color on the cheek than males (but with diffuse edges, unlike the clear division of color in Tree Swallow (Tachykineta bicolor). Juveniles similar to females with dusky cheeks.  

Most similar to its close relative Tree Swallow (photo below), but Tree Swallow is more neatly divided into dark upperparts of a metallic teal blue color and white underparts. The color on the face of Tree Swallow completely surrounds the eye, unlike Violet-green Swallow. Tree Swallows lack the pom-poms at the rump but show considerable white in the same area. A look at a banking bird in flight in good light will usually show the color differences sufficiently to distinguish the two birds and seeing the white almost connecting over the back is an additional indicator of Violet-green Swallow. Violet-green Swallow is somewhat smaller and has a shorter tail and narrower wings than Tree Swallow. When perched, the wings of Violet-green Swallow will extend well past the tip of the bird’s tail. Also similar to White-throated Swift (Aeronautes saxitalis), but that bird lacks the striking colors of Violet-green Swallow.

Trivia: The Latin species name thalassina, meaning “sea green,” refers to the green color of this bird. The genus name Tachykineta means “fast moving.”

Further reading:

Bolander and Parmeter, Birds of Sonoma County California, rev. ed., 2000, p. 89

Brinkley, National Wildlife Federation Field Guide to Birds of North America, 2007, p. 293

Burridge, ed., Sonoma County Breeding Bird Atlas, 1995, p. 108

Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 5th ed., 2006, p. 330

Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 6th ed., 2011, p. 370

Dunne, Pete Dunne’s Essential Field Guide Companion, 2006, pp. 456-457

Ehrlich, Dobkin, and Wheye, The Birder's Handbook, paperback edition, 1988, p. 398

Fix and Bezener, Birds of Northern California, 2000, p. 271

Floyd, Smithsonian Field Guide to the Birds of North America, 2008, p. 329

Kaufman, Field Guide to Birds of North America, 2000, p. 230

Kaufman, Field Guide to Advanced Birding, 2011, pp. 388

Lukas, Bay Area Birds: From Sonoma County to Monterey Bay, 2012, pp. 199-200

Parmeter and Wight, Birds of Sonoma County California, Update (2000-2010), 2012, p. 53

Peterson, Field Guide to Birds of Western North America, 4th ed., 2010, p. 268

Peterson, Western Birds, 3rd ed., 1990,  p. 248

Sibley, Field Guide to Birds of Western North America,1st ed., 2003, p. 312

Stokes, Stokes Field Guide to the Birds of North America, 1st ed., 2010, p. 514

Vuilleumier, American Museum of Natural History, Birds of North America: Western Region, 2011, p. 292

Voice: Cornell Lab of Ornithology: All About Birds--Violet-green Swallow



© 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.


Violet-green Swallow, Cassini Campground, Duncans Mills, May 18, 2013

For comparison: Tree Swallow, Tolay Lake Regional Park, February 9, 2013

Note the even, metallic blue-green upper parts, face cleanly divided (blue-green above, white below) with eye fully surrounded by the colored areas

Violet-green Swallow

Tachykineta thalassina

1990-2013 Sonoma County data. Graph provided by eBird (www.ebird.org), generated September 18, 2013

EBird-reported occurrence in Sonoma County