A practical guide to bird watching in Sonoma County, California

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


Present in the county year round, but more common during migration and in the winter months. Numbers increase from around September and begin to fall off again in late April. Perhaps most common in November, December, and January. Known to nest in Sonoma County, but Peregrine Falcon was among the birds most seriously affected by the use of DDT from the 1940s until sometime after the pesticide was banned in 1972. The chemical causes eggshell thinning and brood failure. Happily, Peregrine Falcon has since made a comeback, and sightings, although not common, are no longer the rarity they had become here. Found near the coast and also inland, in more forested areas. Peregrines hunt for mostly avian prey.

Our largest falcon. Identified by its dark hood and "mustache;" by the wide yellow eyering; by its sharp, hooked beak; powerful yellow feet; dark slaty blue-grey back; and black-barred buff underparts. 

Similar birds include: Merlin (Falco colombarius), Prairie Falcon (Falco mexicanus), and American Kestrel (Falco sparverius)--although the very small, rufous-backed kestrel should cause little confusion. Peregrine Falcon is larger than Prairie Falcon and much larger than Merlin, with Peregrine Falcon averaging about 15-19 inches in height, Prairie Falcon about 14-18 inches, Merlin 10-12 inches (and American Kestrel 7.5-8 inches). Prairie Falcon is brown where Peregrine Falcon is slaty blue-grey. Prairie Falcon has a thinner, less obvious mustache, and, although it shows yellow around the eye, it lacks the broad yellow eyering of the Peregrine. Merlin has a distinctly banded tail, its breast is marked with rufous rather than black, and, as noted above, it is a much smaller bird than Peregrine Falcon.

For current raptor migration information, visit the Golden Gate Raptor Observatory website  

Further reading:

Bolander and Parmeter, Birds of Sonoma County California, rev. ed., 2000, p. 43

Brinkley, National Wildlife Federation Field Guide to Birds of North America, 2007, p. 204

Burridge, ed., Sonoma County Breeding Bird Atlas, 1995, p. 54

Clark and Wheeler, Peterson Field Guide to Hawks of North America, 2nd ed., 2001, pp. 92-93 (Plate 38), pp. 270

Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 5th ed., 2006, p. 140

Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 6th ed., 2011, p. 150

Dunne, Pete Dunne’s Essential Field Guide Companion, 2006, pp. 178-180

Ehrlich, Dobkin, and Wheye, The Birder's Handbook, paperback edition, 1988, p. 248

Fix and Bezener, Birds of Northern California, 2000, p. 118

Floyd, Smithsonian Field Guide to the Birds of North America, 2008, p. 136

Kaufman, Field Guide to Birds of North America, 2000, p. 125

Kaufman, Field Guide to Advanced Birding, 2011, pp. 6, 108, 189, 192, 195

Lukas, Bay Area Birds: From Sonoma County to Monterey Bay, 2012, pp. 80-82, 146

Liguori, Hawks from Every Angle: How to Identify Raptors in the Field, 2005, pp. 85, 94-97, 100, 102-105

Parmeter and Wight, Birds of Sonoma County California, Update (2000-2010), 2012, p. 24

Peterson, Birds of Eastern and Central North America, 5th ed., 2002, p. 116

Peterson, Field Guide to Birds of Western North America, 4th ed., 2010, pp. 110, 114

Peterson, Western Birds, 3rd ed., 1990,  p. 186

Sibley, Field Guide to Birds of Western North America,1st ed., 2003, p. 117

Stokes, Stokes Field Guide to the Birds of North America, 1st ed., 2010, p. 190-191

Vuilleumier, American Museum of Natural History, Birds of North America: Western Region, 2011, p. 107

Voice: Cornell Lab of Ornithology: All About Birds--Peregrine Falcon



© 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.


Peregrine Falcon, December 2010

Peregrine Falcon

Falco peregrinus

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

EBird reported occurrence in Sonoma County