Suzi Eszterhas / Glossy swiftlets (Collocalia esculenta) in cave, Sabah, Malaysia

Suzi Eszterhas / Glossy swiftlets (Collocalia esculenta) in cave, Sabah, Malaysia

Ingo Arndt / Christmas Island Glossy Swiftlets (Collocalia linchii natalis) breeding colony in cave, Christmas Island, Indian Ocean, Australian Territory, endemic

Ingo Arndt / Christmas Island Glossy Swiftlets (Collocalia esculenta natalis) breeding colony in cave, Christmas Island, Indian Ocean, Australian Territory. (These birds are endemic to Christmas Island)

Ingo Arndt / Christmas Island Glossy Swiftlets (Collocalia esculenta natalis) breeding colony in cave, with pile of excrement in foreground. Christmas Island, Indian Ocean, Australian Territory. (These birds are e...

David Tipling / Glossy Swiftlet (Collocalia esculenta) nesting inside house, Cebu, Philippines.

David Tipling / Glossy swiftlets (Collocalia esculenta) inside dwelling near nest, Cebu, Philippines

David Tipling / Glossy swiftlet (Collocalia esculenta) nesting inside dwelling, Cebu, Philippines