World Bird List

Species factsheet
Grey-rumped Treeswift (Hemiprocne longipennis)

Order: Hemiprocne longipennis
Family: Treeswifts (Hemiprocnidae)

Voices can be found here (external link)
Subspecies and Distribution
Subspecie Distribution
harterti s Myanmar to sw Thailand, Malaysia, Sumatra, Borneo and Sulu Arch. (w Philippines)
perlonga islands off w Sumatra
longipennis Java, Bali, Lombok and Kangean Is.
wallacii Sulawesi, Banggai and Sula Is.