Pacific Swallow (Hirundo tahitica) - HBW 9, p. 666

Taxonomy: Hirundo tahitica J. F. Gmelin, 1789, Tahiti.
Forms a superspecies with H. rustica, H. lucida, H. angolensis, H. neoxena, H. albigularis and H. aethiopica; sometimes treated as conspecific with H. neoxena, but differs morphologically (especially in bill size and in tail structure and markings). Sometimes split into two species, based on E “nominate group” (also including ambiens and subfusca) and paler W “javanica group”, but racial variation is clinal throughout; the groups meet in W Melanesia, where birds in New Britain (ambiens) are intermediate between the two, and individuals on Long I (in S Bismarck Sea) appear intermediate between New Britain and N New Guinea populations. Further, race domicola has been considered a separate species by some, in part because of its geographical isolation from other races and its greenish, rather than blue, gloss; taxonomic status requires review. Race frontalis not well differentiated, also has been thought to include individuals from Wallacea, but they probably belong with javanica; birds from Philippines and Borneo (and sometimes those W to Malay Peninsula and S to Sumatra) intergrade with latter, and generally indistinguishable from it, but sometimes treated as a separate race abbotti (with which mallopega from N Philippines synonymized). Eight subspecies recognized.