Introduction
The Mountain Swiftlet, Aerodramus hirundinaceus, is a small swift in the family Apodidae. It is endemic to New Guinea and several nearby islands, where it inhabits mountainous country from about 500 metres above sea level to the upper forest limit. The species is adapted to fast, aerial feeding and uses echolocation to navigate its breeding caves.
Physical Description
The Mountain Swiftlet is a medium-sized swiftlet, measuring approximately 11–13 centimetres in length. It has dark brown to brownish-grey upperparts, paler grey underparts and a slightly forked tail. The plumage can show a subtle bluish sheen in good light, but the species is generally plain and difficult to identify while in flight.
The sexes are alike in appearance. Geographic variation has been reported, including darker, browner plumage in some island forms and larger birds in the highest parts of the New Guinea range. The legs and feet are feathered, a useful feature when distinguishing it from some similar swiftlets, although this is rarely visible on a flying bird.
Range and Habitat
The Mountain Swiftlet occurs in the highlands of New Guinea, including both Indonesian Papua and Papua New Guinea. It also occurs on nearby islands including Karkar, Goodenough and Yapen, although taxonomic treatment of some island forms has varied.
It is primarily a bird of tropical moist montane forest, highland valleys, open country near mountains and other upland habitats. It is usually found from approximately 500 metres to the treeline, with occasional records at lower elevations near hills. The species breeds in caves, but it normally forages well outside the cave system over forest, clearings and mountain slopes.
Where to See This Species
Variarata National Park, Central Province, Papua New Guinea
Mountain Swiftlets are included in the documented bird list for Variarata National Park. The park’s forested hills and upland surroundings provide suitable habitat, although swiftlet identification can be difficult because several swift species may occur in the same region. Look overhead in open areas and above the forest canopy, particularly during periods of active insect movement.
Nearby accommodation: Port Moresby is the practical gateway, with hotels, guest houses and self-catering accommodation available in and around the city.
Lorentz National Park, Papua Province, Indonesia
Mountain Swiftlets are recorded from Lorentz National Park, which protects a vast elevational range from lowland environments to the high mountains of western New Guinea. The most suitable areas to search are the park’s montane and alpine margins, where swiftlets may be seen feeding over forest, valleys and open slopes.
Nearby accommodation: Timika is the main practical gateway, with hotels and guest houses, although access to the park’s mountain areas generally requires local arrangements and specialist transport.
Behaviour and Diet
The Mountain Swiftlet is active by day and spends much of its time in fast, agile flight. It feeds on small flying insects, including flies, beetles, moths and other aerial invertebrates, which it captures above forest, valleys and open mountain slopes.
It is a social species and may forage in groups, sometimes with other swiftlets. Identification from the ground is often difficult because swiftlets move rapidly and several species can occur together. The species is resident rather than a long-distance migrant, although local movements may occur in response to weather and food availability.
Mountain Swiftlets breed in caves, where they construct shallow nests on ledges or cave walls. The nests are made mainly from materials such as lichens, rootlets, grasses or other vegetation, held together with a relatively small amount of saliva. A documented study in Papua found that the usual clutch was one egg, incubated by both parents. Breeding activity peaked between October and December in the study cave, although occupied nests were found during much of the year. Fledging occurred after approximately 67–74 days.
Identification Tips
- Look for a small to medium-sized swiftlet with dark brown upperparts, paler grey underparts and a slightly forked tail.
- The species is most often identified by its combination of upland habitat, flight behaviour and range rather than by a single obvious plumage mark.
- Some individuals may show a slightly paler rump or subtle bluish tones above in bright light.
- It can be confused with the Uniform Swiftlet, Aerodramus vanikorensis, which may occur in overlapping areas. These species can be extremely difficult to separate in flight, and uncertain records are best treated cautiously.
- The Mountain Swiftlet has feathered legs, but this feature is usually visible only at close range or in photographs.
- Echolocation clicks may be heard near breeding caves, but sound alone should not be relied upon for identification away from caves.
Conservation Status
The Mountain Swiftlet is assessed as Least Concern. It has a broad distribution across New Guinea and is recorded from several protected areas. A reliable global population estimate is not available, and the population trend is not well documented.
The species may be affected locally by the loss or degradation of montane forest, disturbance of breeding caves and changes to upland habitats. However, the scale of these pressures and their effect on the global population remain uncertain. Protecting mountain forests, maintaining cave habitat and limiting unnecessary disturbance at breeding sites are appropriate conservation measures.
Frequently Asked Questions
Where is the Mountain Swiftlet found?
The species is found mainly in the mountains of New Guinea, including Indonesian Papua and Papua New Guinea, with additional populations on nearby islands such as Karkar, Goodenough and Yapen.
What does the Mountain Swiftlet eat?
It feeds mainly on small flying insects, which it catches in the air while flying over forests, mountain slopes, valleys and other open habitats.
Can the Mountain Swiftlet echolocate?
Yes. Like several cave-nesting swiftlets, it produces clicking sounds that help it navigate in dark breeding caves.
Where does the Mountain Swiftlet build its nest?
It builds a shallow nest on a ledge or wall inside a cave. The nest is made from materials such as lichens, rootlets and other vegetation held together with saliva.
How many eggs does it lay?
The documented breeding study found a clutch of one egg. Both parents incubate the egg and feed the chick after hatching.
Is the Mountain Swiftlet threatened?
It is currently assessed as Least Concern, although local habitat loss, cave disturbance and degradation of montane environments may affect some populations.
References
- BirdLife International
- Michael K. Tarburton, Emu: Austral Ornithology
- Avibase, World Bird Database
Related posts
