Masked Booby Sula dactylatra
Three species of boobies once absent along the coast of southern California became rare visitors there during the last two decades of the 20th century. Increasing ocean temperatures then favored tropical ocean birds wandering north. A Masked Booby on the coast of San Diego County in winter 2001–2002 remained 12 days, to be seen and photographed by crowds of birders.
Winter: A subadult Masked Booby rested with pelicans and cormorants on the rocks at La Jolla Cove (P7) 30 December 2001–10 January 2002 (M. Burcham, Garrett and Wilson 2003). The bird then evidently moved north to Corona del Mar, Orange County, where it was caught on 12 January 2002 (Cole and McCaskie 2004). The nearest pelagic record is of one 22 miles southwest of the south end of San Clemente Island 10 January 1977, the first record for California waters (Lewis and Tyler 1978). A Masked Booby reported from San Elijo Lagoon (L7) 14 November 1987 was not accepted by the California Bird Records Committee because of uncertainty over whether the bird was actually a Red-footed Booby (Patten and Erickson 1994).
Taxonomy: The bill color of the bird at La Jolla was close enough to that of an adult to identify it as a Masked Booby rather than the more orange-billed Nazca Booby (S. granti), confirmed to be a species distinct from the Masked by Pitman and Jehl (1998). No specimen of the Masked Booby has been collected in California. Sula d. californica Rothschild, 1915, breeds in the eastern tropical Pacific; S. d. personata Gould, 1846, breeds in the central Pacific.
Blue-footed Booby Sula nebouxii
Unlike the eastern Pacific Ocean’s other boobies, the Blue-footed does not stray far from land, and it does not frequent the west coast of Baja California. Most or all of its sporadic incursions across the international border come by way of the Gulf of California, making the Salton Sea the species’ primary location in the United States. Of the seven records for San Diego County, none is more recent than 1980.
Migration: Representing dispersal north after breeding, all but one of the San Diego County records of the Blue-footed Booby fall between 4 August and 4 October: at sea off San Diego 4 October 1964 (AFN 19:78, 1965), Ocotillo Wells (I28/I29) 4 August 1968 (SDNHM 36707), bridge of Interstate 15 over Lake Hodges (K11) 8 September 1969 (SDNHM 37566), off Imperial Beach (V10) 6 September 1971 (AB 36:119, 1972), Lake San Marcos (I8/J8) late August–14 December 1972, when found dead (AB 27:120, 1973), and Camp Denver Fox 3.1 miles northwest of Lake Henshaw (F16) 18 August 1977 (AB 32:256, 1978; photo SDNHM). The exception is of one seen 2 miles off Camp Pendleton 16 March 1980 (Roberson 1993). The California Bird Records Committee did not accept the identification of one off Point Loma 26 August 1977, though this report, like most of the others, came during irruptions of the Blue-footed Booby to the Salton Sea (Roberson 1993).
Taxonomy: Nominate S. n. nebouxii Milne-Edwards, 1882, occupies the species’ entire range except for the Galapagos Islands.
Brown Booby Sula leucogaster
Of the boobies (and other tropical ocean birds) whose occurrences in California accelerated with the ocean warming of the late 20th century, none accelerated more than the Brown Booby. There was only one record along the California coast before 1983; since then, over 40 records have accumulated. In northwestern Baja California, the Brown Booby has been seen repeatedly on Todos Santos Islands off Ensenada, with a male carrying sticks and displaying in 2000 (Palacios and Mellink 2000), and on Los Coronados Islands off Tijuana, with up to six individuals in 1999 and 2002 and two pairs apparently nesting in the latter year (NAB 56:489, 2002).
Migration: In San Diego County, the Brown Booby is known from eight records, five accepted by the California Bird Records Committee. An adult male injured by a fish hook was picked up at Imperial Beach (V10) 2 April 1990 (SDNHM 46566). An immature was on the ocean 2 miles southeast of the entrance to San Diego Bay 14 December 1991 (D. W. Povey; Patten et al. 1995b). An immature at Point Loma (S7) 27–29 September 1997 was captured for rehabilitation (M. F. Platter-Rieger; Rogers and Jaramillo 2002). Adults were 10 miles southwest of Point Loma 11 September 1999 (M. B. Mulrooney; Rogers and Jaramillo 2002) and at Point Loma 8 April 2001 (R. E. Webster; Cole and McCaskie 2004). A Brown Booby at Shelter Island (R8) 17 November 1997 was afflicted with bumblefoot, leading the records committee to question whether the bird had been kept in captivity for an extended period (Erickson and Hamilton 2001). Reports of an adult male at La Jolla (P7) 4 February 1998 and presumably the same bird at Point Loma three days later have not been assessed by the committee (P. Lonsdale, R. B. Riggan; FN 52:256, 1998).
Taxonomy: It is fortunate that the specimen from Imperial Beach is an adult male, because geographic variation in the Brown Booby is expressed in adult males only. It is S. l. brewsteri Goss, 1888, breeding on islands in the Gulf of California and farther south along the west coast of Mexico. In brewsteri males have the head whitish but not as pale as in S. l. nesiotes Heller and Snodgrass, 1901, of Clipperton Atoll.
Red-footed Booby Sula sula
First identified in California in 1975, the Red-footed Booby was known in the state from 14 well-supported records by 2002. Like those of the Masked and Brown Boobies, occurrences of the Red-footed accelerated with ocean warming. San Diego County has two records.
Migration: An immature was videotaped at La Jolla (P7) 24 May 1996 (P. Lonsdale; McCaskie and San Miguel 1999). Another caught on a fish hook at Scripps Institution of Oceanography (O7) 20 July 2002 was captured for rehabilitation (Cole and McCaskie 2004). The report of one within 1 mile of shore off La Jolla 13 August 1993 (AB 48:151, 1994) was not accepted by the California Bird Records Committee (Erickson and Terrill 1996). A booby at San Elijo Lagoon 14 November 1987 was reported as a Masked but the observer’s description suggests it was a Red-footed.
Taxonomy: The subspecies of Red-footed Booby reaching California is uncertain; S. s. websteri Rothschild, 1898, breeds in the eastern tropical Pacific; S. s. rubripes Gould, 1838, breeds in the central Pacific.