Island Swiftlet / Yågaguak (Chachaguak)
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Island Swiftlet / Yågaguak (Chachaguak)
Aerodramus vanikorensis bartschi
Subspecies endemic to the Marianas. Endangered species.
Swiftlet on nest.
Locally known as "yåyaguak", Island Swiftlets nest in limestone caves and were once commonly found throughout the island. In 1993, the yåyaguak population stood at only about 500 birds. Most of the remaining yåyaguak live in a single cave on Naval Magazine in southern Guam and feed in the Talofofo River Valley. The exact cause of the decline of this species is not known, however, predation by brown tree snakes or pesticides are possible reasons.
Yåyaguak spend long periods of each day flying while searching for tiny aerial insects to feed on. The birds swoop and dart through the sky as they chase their food. The wings of yåyaguak are long, narrow and pointed, which allows the birds to be fast fliers.
Females lay one egg several times per year in shallow nests made of moss, which are fastened to cave walls by the bird's saliva. When the babies hatch, they immediately hook their tiny toes in the nest moss, which keeps them from falling out. Adult birds find their way in and out of dark caves using echolocation. This means that the birds make clicking sounds that bounce off the walls and other objects in the cave, telling them how far away the objects are. The yåyaguak is listed on both the Guam and U.S. endangered species lists, which means that it is against local and federal law to kill, harm, capture, or harass the birds in any way.
Guam Comprehensive Wildlife Conservation Strategy, 9/27/2005
