A practical guide to bird watching in Sonoma County, California
(Unless otherwise indicated, all phone numbers are in the 707 area code)
Ross's Goose is very uncommon in Sonoma County, but relatively easy to see here, as a single bird has taken up permanent residence at Petaluma's Lucchesi Park (present at least through the summer of 2013, the bird was first reported February 22, 1999). Otherwise, Ross's Goose is mostly noted here as an occasional flyover or as a stray with other migrating geese. Has been reported most frequently in the Bodega Bay area, but records are not numerous. In the winter of 2011-2012, another individual stayed at Roberts Lake Park, in Rohnert Park, and is showing signs of staying around. Ross's Goose breeds mostly in the far north of Canada on tundra. Winters well to the south of us, but large numbers land in California inland and to the north during migration to rest before moving on. Commonly associates with Snow Goose (Chen caerulescens) and other geese.
Distinguishable from other geese mainly by its very small size (about 23" or 58cm long). Looks rather like a miniature Snow Goose (also rare in Sonoma County), but there are notable differences besides size. Ross's Goose has a distinctly rounded head, whereas Snow Goose has a squarer, slightly blocky head. Ross's Goose has a very small bill relative to its head size (usually reddish pink), and the line formed by the base of the bill at its point of conjunction with the feathered parts of the head is a fairly straight vertical line. In Snow Goose, the line of conjunction is distinctly incurved in the direction of the bill tip. Ross's Goose lacks the "grin patch" often noted as diagnostic for identifying Snow Goose (a horizontally elongated dark area at the bottom edge of the bill that makes the bird look like it's smiling; the Sibley and Peterson guides have good illustrations, also see the photo below). Base of bill often greenish and warty in Ross's Goose. Ross's Goose has a proportionately shorter neck. Both birds are white all over, except for black flight feathers, the tips of which usually show when the birds are at rest with wings folded (and conspicuous in flight). Note, however, that both Ross's Goose and Snow Goose have rare dark morphs--very rare in the case of Ross's Goose. Juvenile Ross's Goose may have slight greyish washes on the head and back. Juvenile Snow Goose shows much more grey than juvenile Ross's Goose, especially on the back.
Selected County sightings: Roberts Lake (December 16, 2011, Colin Talcroft); Roberts Lake (March 30, 2011, Steve Bryan); Lucchesi Park (permanent resident, last noted in July 2013)
Further reading:
Bolander and Parmeter, Birds of Sonoma County California, rev. ed., 2000, p. 27
Brinkley, National Wildlife Federation Field Guide to Birds of North America, 2007, p. 61
Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 5th ed., 2006, p. 22
Dunn and Alderfer, eds., National Geographic Field Guide to the Birds of North America, 6th ed., 2011, p. 16
Dunne, Pete Dunne’s Essential Field Guide Companion, 2006, p. 25-26
Ehrlich, Dobkin, and Wheye, The Birder's Handbook, paperback edition, 1988, p. 56
Fix and Bezener, Birds of Northern California, 2000, p. 72
Floyd, Smithsonian Field Guide to the Birds of North America, 2008, p. 33
Kaufman, Field Guide to Birds of North America, 2000, p. 48
Kaufman, Field Guide to Advanced Birding, 2011, pp. 142
Lukas, Bay Area Birds: From Sonoma County to Monterey Bay, 2012, p. 283-284
Parmeter and Wight, Birds of Sonoma County California, Update (2000-2010), 2012, p. 4
Peterson, Birds of Eastern and Central North America, 5th ed., 2002, p. 60
Peterson, Field Guide to Birds of Western North America, 4th ed., 2010, pp. 16, 22
Peterson, Western Birds, 3rd ed., 1990, p. 38
Sibley, Field Guide to Birds of Western North America,1st ed., 2003, p. 68
Stokes, Stokes Field Guide to the Birds of North America, 1st ed., 2010, p. 10
Vuilleumier, American Museum of Natural History, Birds of North America: Western Region, 2011, p. 41
Voice: Cornell Lab of Ornithology: All About Birds--Ross's Goose
© 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.
Ross's Goose, Lucchesi Park, Petaluma (permanent resident)
For comparison: Snow Goose, Ellis Creek Water Treatment Facility, Petaluma, April 7, 2012
Note the dark "grin patch" along the lower side of the bill and the curved junction between the bill and the white face. Head more elongated than in Ross's Goose.
Ross's Goose
Chen Rossii
1990-2013 Sonoma County data. Graph provided by eBird (www.ebird.org), generated August 4, 2013
EBird-reported occurrence in Sonoma County
