The Mariana swiftlet or Guam swiftlet is a species of swiftlet in the family Apodidae.
Region
Micronesia, Western Pacific
Typical Environment
Found on limestone islands where it roosts and breeds in humid caves amid karst terrain. It forages over native forest canopies, secondary growth, coastal areas, and occasionally agricultural clearings. Colonies are sensitive to disturbance and predation at cave entrances. Now greatly reduced or absent on Guam due to invasive predators, with strongerholds on islands to the north.
Altitude Range
Sea level to 500 m
Climate Zone
Tropical
Ease of Keeping
Beginner friendly: 1/5
Also called the Guam swiftlet, this cave-nesting swiftlet uses saliva to glue a shallow nest to limestone walls and can navigate in darkness with audible clicking echolocation. It feeds on aerial insects high over forests and coasts. Populations have declined, especially on Guam, largely due to predation by the introduced brown tree snake and disturbance at roosting caves.
Temperament
social and active
Flight Pattern
fast, agile flier with rapid wingbeats and long, scythe-like wings
Social Behavior
Nests colonially on cave walls, with pairs defending only a small area around the nest. Typically lays a single egg, with both parents incubating and feeding the chick. Uses echolocation clicks inside caves to navigate to nests in darkness.
Migratory Pattern
Resident
Song Description
A mix of thin, high-pitched twitters and chips given in flight over feeding areas. Inside caves it produces distinctive clicking sounds used for echolocation rather than song.
Plumage
Sooty-brown to dark gray overall with slightly paler underparts and a faintly notched tail; sleek, glossy look with narrow, pointed wings.
Diet
Feeds on small flying insects such as ants, termites, beetles, flies, and moths caught on the wing. Often exploits swarming events, especially after rains. Captures prey with a wide gape during sustained aerial foraging and opportunistically over habitat edges.
Preferred Environment
Forages above forest canopies, along coastal cliffs, and over open clearings and roads where insects concentrate. Frequently commutes between roost caves and nearby feeding grounds along ridgelines and valleys.
