Grey-rumped Treeswift (Hemiprocne longipennis) [XC21017]
by David Edwards from Karimata island, off West Kalimantan, Borneo, Indonesia (call)
Grey-rumped Treeswift (Hemiprocne longipennis) [XC290535]
by Peter Boesman from River trail. Taman Negara, Pahang, Malaysia (flight call)
Subspecies
Forms a superspecies with Crested Treeswift (Hemiprocne coronata), with which formerly sometimes treated as conspecific. Several subspecies have been described, but most nowadays considered invalid, e.g. ocyptera (Nias I), thoa (Batu Is, Pagi Is, Enggano I) and anochra (Natuna Is).
The following 4 subspecies are recognised:
harterti Stresemann, 1913 - Southern Myanmar (southern Tenasserim) and south-western Thailand southern and east to Sumatra, Borneo and intervening islands, and Sulu Archipelago east to Tawitawi (Philippines).
perlonga (Richmond, 1903) - Western Sumatran islands from Simeulue to Enggano.
longipennis (Rafinesque, 1802) - Sunda Strait (Panaitan I) through Java to Lombok, and Kangean Is (eastern Java Sea).
wallacii (Gould, 1859) - Sulawesi, including southern and eastern satellites, and Sula group (western Moluccas).