Mariana Gray Swiftlet
Yǻyaguak: Endangered species
Scientific Name: Collocali. bartschi (Family APODIDAE)
Common Name: Mariana Gray Swiftlet
Chamorro Name: Yǻyaguak
Audio sample of the Yǻyaguak
Habitat and Natural History: These birds live in limestone caves and sink holes in limestone and ravine forests. Their nests are constructed of moss are fastened to the roofs of caves with saliva. As an aerial feeder, it uses echolocation to capture flying insects. It eats flies, winged ants and termites.
Description: Small body, narrow winged. Dark gray above body, brownish gray below. It lays a single egg sometime between January and July. The chick is tended for about thirty-five days before fledging. It is not known whether both parents tend the chicks.
Range: Historically, the Island Grey Swiftlet was found on Guam and the Northern Mariana islands of Rota, Aguigan and Saipan. The Rota population inexplicably disappeared after World War II. The subspecies is endemic to the Mariana Islands. On Guam it is restricted to several caves in the south.
Current Status: It is listed as endangered by the U.S. Fish and Wildlife Service, Government of Guam and Government of the Commonwealth of the Northern Mariana Islands.
Threats: The main threat is predation by the brown treesnake.