Grey-rumped Treeswift (Hemiprocne longipennis) [XC290537]
by Brian Cox from Base of new road to Fraser's Hill. The Gap, Pahang, Malaysia (call)
Grey-rumped Treeswift (Hemiprocne longipennis) [XC684816]
by Ding Li Yong from Ang Mo Kio Town West Park, Singapore (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).