We report here on 20 years of records which establish the Canada Goose (Branta canadensis) as a breeding bird in the San Francisco Bay area. In California, this species is generally not considered to breed regularly south of the northeastern corner of the state (Kortright 1943:86, Johnsgard 1975). Occasional breeding records have been recorded for the Lake Tahoe area (Grinnell and Miller 1944), and more recently from Bridgeport Reservoir in Mono County (Gaines 1977:6). Additional instances of breeding are known from a reservoir east-southeast of Marysville, Yuba County (F. Kozlik, Calif. Dept. Fish and Game, pers. comm.). In the spring of 1932 a single pair nested on Crystal Springs Reservoir in San Mateo County (Moffitt 1939). Starting in 1959, however, a breeding colony became established on Brooks Island, Contra Costa County, and has probably bred there every year since that time (2 to 16 adults seen each year).