Red-billed Tropicbird Phaethon aethereus

The Red-billed Tropicbird reaches the northern limit of its usual oceanic range at the latitude of San Diego.  In late summer and early fall it is regular but rare.  Though it has been seen as close as five miles from the coast, the only records from land are of dead birds washed ashore.

Migration: Away from the islands where it nests, the Red-billed Tropicbird is highly pelagic.  On a trip west from San Diego, often a boat must pass the south end of San Clemente Island 60 miles west of San Diego before the first tropicbird appears.  The sightings nearest land are from 5 miles west of Point Loma (Sefton 1938, Abbott 1941).  On shore, dead birds have been found at Coronado (T9) 21 September 1983 (SDNHM 42568), at Imperial Beach (V10) 4 August 1984 (SDNHM 47804), and at San Onofre (C1) 7 October 2001 (SDNHM 50607).  Most records are for September; dates extend from 5 May (1987, near Tanner Bank about 100 miles west of Point Loma, R. R. Veit, AB 41:487, 1987) and 10 May (1969, 10 miles west of Imperial Beach, AFN 23:625, 1969) to 7 October.

Conservation: Sightings of several individuals per day, as on some trips between San Diego and San Clemente Island from the 1960s to 1982, have not been repeated since.  The maximum count is still nine on 27 July 1968 (AFN 22:647, 1968).

Taxonomy: The subspecies of Red-billed Tropicbird in the eastern Pacific Ocean is P. a. mesonauta Peters, 1930.