The status of two species of migrant swifts in Java and Sumatra (Aves, Apodidae)

Apus pacificus pacificus (Latham) The occurrence of Apus pacificus in Java, as a migrant from the north, was established by Vorderman (1900), who collected a specimen in 1896: "in de Preanger, bezuiden de Salak". Soon afterwards, the species was also recorded by Bartels (1902, 1906). In later years specimens from Java were generally listed as belonging to the nominate race (Bartels Jr. & Stresemann, 1929; Chasen, 1935; Kuroda, 1936; Hoogerwerf, 1948). Deignan (1956) identified a specimen from the Semangko Pass, Malaya, as belonging to the race Apus pacificus kanoi Yamashina, and subsequently Vaurie (1965: 654, 655) expressed the opinion that birds reported from the southern Malay Peninsula, Sumatra and Java are "probably" referable to this subspecies, which was described in 1942 and therefore had not been considered previously. It is apparent that Vaurie had not examined material from Java, so that the subspecific identity of birds from Java remained in doubt. Vaurie's surmise that the birds visiting Java belonged to the race kanoi may well have been partly based on the assumption that this more southern race would have its winter-quarters less far south than the nominate race. The need to incorporate the series of A. pacificus from the Bartels collection in our main collection, gave me an opportunity to investigate this problem. Altogether we have 37 specimens from Java, and without exception they are referable to the nominate race, Apus p. pacificus. For comparison I had a series from eastern Siberia and Japan (including six from Vladivostok, regarded as typical of the nominate race), and two recent specimens of A. p.