Figures 164, 165 (above, right). The CBRC has endorsed records involving 11 Sooty Terns. The first involves a juvenile that appeared in the wake of a 1982 tropical storm, but the rest refer to birds at least a year old, including three pairs. These photos depict the most widely seen bird, an adult that returned to Bolsa Chica in Orange County each year from 1994 to 1998. The photo above was taken on 10 August 1994 (1994-109; Peter Knapp) and the photo at right was taken on 14 June 1997 (1997-089; Larry Sansone).

Figure 165.

 

Figure 166. Impressions of the Sooty Tern at Bolsa Chica in Orange County, 8 August 1996 (1996-084; Tim Manolis).

Click image for larger view.

 

 

 

 

 

 

SOOTY TERN Onychoprion fuscatus (Linnaeus, 1766)

Accepted: 11 (73%)	Treated in Appendix H: no
Not accepted: 4	CBRC review: all records
Not submitted/reviewed: 4	Color image: none

This species, like the similar Bridled Tern, plies tropical and subtropical waters across much of the globe. The breeding ranges of these two species overlap to a considerable degree, but the Sooty is far more abundant and occurs over a wider area, nesting on islands that are far from any continent. The species is found across the tropical Pacific Ocean, and in the eastern Pacific it nests on several Mexican islands, including Rocas Alijos, the Islas Revillagigedo, and Clipperton Atoll. Limited numbers breed along the Gulf coast, and some dispersing birds follow the Gulf Stream regularly to waters off North Carolina and casually farther north as far as Nova Scotia. Tropical cyclones regularly force this species well inland in the East (as far as southern Ontario), and such storms have generated many extralimital records in the northwestern Pacific Ocean (Gould 1974). An extreme example involves the remains of an apparently storm-blown bird salvaged in early September 1997 at Attu in the western Aleutian Islands (Dickerman et al. 1998). Apart from California’s records, a 24 July 1994 sight record from Estero Punta Banda in northwestern Baja California represents the species’ only documented occurrence in temperate waters of the eastern Pacific.

California’s first Sooty Tern, a first-fall bird, was found on 27 September 1982—in the wake of hurricane Olivia, which dissipated off northwestern Baja California—at the mouth of the San Diego River in San Diego County (Webster et al. 1990). Young Sooty Terns forage over schools of tuna in the eastern tropical Pacific (Au and Pitman 1986), where Olivia originated. A dozen years later, in summer 1994, an adult Sooty Tern was attracted to the Elegant Tern colony at Bolsa Chica in Orange County, where it made appearances each spring/summer through 1998 (Figures 164–166). This bird’s behavior suggested that it might attempt to breed there, with or without another Sooty Tern. In 1997 a pair did, in fact, lay a single egg at the south end of San Diego Bay, San Diego County. This nesting attempt failed, however, when a Peregrine Falcon killed the adults (Smith 1999). A pair seen at Bolsa Chica from 19 to 25 July 1996 (which did not include the long-staying adult previously mentioned) may have been the same ill-fated duo, but most CBRC members concluded otherwise.

Most recently, on 21 August 2001, a Sooty Tern several miles off Tomales Pt., Marin County, established the second northernmost record for the Pacific coast, albeit well south of the remarkable specimen from Alaska.