Collocalia sawtelli The Atiu swiftlet or Sawtell's Swiftlet (Aerodramus sawtelli) is a species of bird in the swift family, endemic to Atiu in the Cook Islands.

This small, dark swift measures 10 cm (3.9 in) long.

[2] Its natural habitats are the island's fernlands and mixed horticultural areas over which it feeds, and in makatea limestone caves within which it nests.

[2] The species is known on Atiu as kopeka.

Unlike all other swiftlets, it echolocates only through single clicks, rather than a mix of single- and double clicks.