The Mariana Swiftlet (Aerodramus bartschi) (Aves: Apodidae) is endemic to the Mariana Islands, where it currently occurs on Saipan, Aguiguan, and Guam. An introduced population of Mariana Swiftlets is also present on O'ahu in the Hawaiian Islands. Sparing interference with the endangered population in the Marianas, the introduced, surrogate population...