American Oystercatcher Haematopus palliatus

The American Oystercatcher ranges widely, if not continuously, along the Pacific coast of the Americas from Chile north to Mexico.  The normal distribution falls barely short of the United States: up to four individuals are seen regularly on Los Coronados Islands off Tijuana, though they are not confirmed to breed there.  In southern California the species is rare, most frequent on the Channel Islands.

Migration: There are only two records of apparently pure American Oystercatchers in San Diego County.  Cooper (1868) collected one at San Diego 16 May 1862 (MVZ 4488).  Over a century passed until the next, seen at Point Loma 20–21 April 1978 (Luther et al. 1983).  Another oystercatcher photographed at Point Loma 11 March–7 May 1992 was a hybrid between the American and the Black (Erickson and Terrill 1996).

Taxonomy: The subspecies of the American Oystercatcher reaching southern California is H. p. frazari Brewster, 1888, darker on the back and with less white than the nominate subspecies of the Atlantic coast.  In northern half of Baja California the American Oystercatcher hybridizes frequently with the Black Oystercatcher (Jehl 1985).

Black Oystercatcher Haematopus bachmani

Though a fairly common resident on Los Coronados Islands, the Black Oystercatcher is just a rare visitor on the nearby coast of San Diego County, seen at all seasons.  The oystercatcher frequents natural rocky shorelines, occasionally jetties of riprap.  In 2003 a pair was courting on Zuñiga Jetty at the mouth of San Diego Bay—they may have nested and fledged one young.

Winter: Point Loma (S7) and La Jolla (P7) are the primary sites for the Black Oystercatcher in San Diego County.  From 1997 to 2002 (all seasons combined) we recorded two sightings at Point Loma, three at La Jolla, plus one from the north end of Sunset Cliffs Natural Park (R7; 24 April 2000, V. P. Johnson).  All sightings during the atlas period were of one or two individuals, but up to five were at Point Loma 20 March–2 May 1992 (B. and M. McIntosh, AB 46:480, 1992).  Three were at Imperial Beach (V10) 24 September 1980 (AB 35:226, 1981), and one was there 1 May and 13 June 1982 (D. Parker, E. A. Cardiff, AB 36: 894, 1016, 1982).  The only record for northern San Diego County is of one on the breakwater for the Oceanside harbor (H5) 7 February 1987 (J. O'Brien, AB 41:328, 1987).

 

Migration: Records of the Black Oystercatcher in San Diego County form no clear seasonal pattern. 

Breeding distribution: On 16 May 2003, Robert T. Patton found a pair in courtship display and apparently prospecting for nest sites on Zuñiga Jetty (S8).  The birds were seen regularly through 13 June, then disappeared (during incubation?) until 9 July.  On 23 July, the last date the oystercatchers were seen at this site in 2003, there were three birds, suggesting a possible juvenile (D. M. Parker, M. Sadowski, L. Norton).

Conservation: Before 1972 the only specific record of the Black Oystercatcher in San Diego County was of the single specimen, collected at Coronado (T9) 2 June 1915 (SDNHM 20645).  Since 1977 the species has occurred nearly annually.  The possible colonization in 2003 may be part of a continuing trend to slow increase.