Introduction
The Cave Swiftlet, also known as the Linchi Swiftlet, is a small, fast-flying member of the swift family Apodidae. Its accepted scientific name is Collocalia linchi. It is associated with caves and other sheltered roosting sites, but usually spends the day feeding over forests, farmland, wetlands and settlements. Unlike several related swiftlets, the Cave Swiftlet is not currently regarded as an echolocating species.
Physical Description
The Cave Swiftlet is a small swift, measuring roughly 10–12 centimetres in length. It has dark brown to blackish upperparts, often with a subtle gloss, and paler brown or grey-brown underparts. The throat and breast are usually darker than the lower belly, while the tail is short and slightly forked.
Males and females are not generally separable by plumage in the field. Juveniles may appear duller and less sharply contrasted than adults. As with many swiftlets, identification is difficult because several species share similar dark plumage and aerial behaviour.
The original article described a wingspan of about 30 centimetres, but this figure is not retained because reliable modern measurements are not consistently available for the species and swiftlet measurements can vary according to method.
Range and Habitat
The Cave Swiftlet is principally an Indonesian species, occurring on Sumatra, Java, Bali and Lombok, with geographic variation recognised among some populations. Taxonomic treatments have differed in the past, particularly over populations from Borneo and nearby islands. The Bornean mountain form historically associated with C. linchi is now generally treated separately as the Bornean Swiftlet, Collocalia dodgei.
It uses a wide range of lowland and upland habitats, including woodland, forest edges, cultivated areas, open country and urban surroundings. Caves, limestone overhangs, tunnels and suitable buildings may provide nesting or roosting sites. The species is resident rather than a long-distance migrant, although local movements may occur as birds track insect abundance and suitable feeding conditions.
Where to See This Species
Alas Purwo National Park, East Java, Indonesia
The park’s published bird checklist includes the Cave Swiftlet. Forest edges, open areas and the vicinity of limestone formations provide suitable places to watch small swiftlets feeding overhead, although separating this species from other swiftlets may require experience or photographic confirmation.
Nearby accommodation: Banyuwangi is the main practical gateway, with hotels, guest houses and other visitor accommodation. Smaller accommodation is also available near park access points.
Bali Barat National Park, Bali, Indonesia
The Cave Swiftlet is included in the park’s bird checklist. The park combines dry forest, woodland, coastal habitats and open areas, offering opportunities to observe swiftlets in flight, particularly over clearings and forest margins.
Nearby accommodation: Gilimanuk and Negara provide the most practical bases, with hotels, guest houses and other accommodation suitable for visitors exploring the park.
Gunung Merbabu National Park, Central Java, Indonesia
The Cave Swiftlet is recorded on the national park’s bird checklist. Its presence at a montane site illustrates the species’ ability to use habitats well above the lowlands, although sightings are most likely over open slopes, forest edges and clearings rather than inside dense forest.
Nearby accommodation: Selo and the wider Boyolali area provide guest houses, homestays and other basic accommodation used by visitors to the park.
Behaviour and Diet
Cave Swiftlets are active by day and usually spend much of their time in rapid, agile flight. They are gregarious and may gather in loose flocks while feeding or returning to communal roosts. Their flight is generally faster and more direct than that of many swallows, with frequent changes of direction as they pursue airborne prey.
The diet consists mainly of small flying insects, including flies, beetles, ants, termites and other aerial invertebrates. Feeding commonly takes place over vegetation, open ground, water and human-modified landscapes. By consuming large numbers of insects, the species contributes to the aerial insect-predator community of its habitat.
Breeding takes place in sheltered sites such as caves, crevices, tunnels and buildings. The nest is a small cup attached to a vertical surface and is constructed primarily with sticky saliva, sometimes with additional fine material. Cave Swiftlet nests should not automatically be confused with the commercially valuable nests of other swiftlet species, particularly the White-nest and Black-nest Swiftlets.
Although swiftlets are often associated with echolocation, research has found that the Cave Swiftlet does not echolocate in the same confirmed manner as several Aerodramus species. It relies mainly on vision and ordinary flight calls when moving through its environment.
Identification Tips
- Look for a small, dark swift with a short, slightly forked tail and rapid, purposeful flight.
- The plumage is generally darker and less strongly patterned than that of many swallows.
- Watch for birds feeding over woodland edges, open fields, villages, wetlands and forest clearings.
- Do not identify the species solely from its use of a cave. Several swiftlets may share the same cave system or surrounding feeding habitat.
- Distinguishing the Cave Swiftlet from the Glossy Swiftlet and other Collocalia species can be difficult without a clear view, photographs, calls or local knowledge of the species present.
- The species is smaller and generally less glossy than some larger, commercially harvested swiftlets, but size and gloss can be misleading in poor light or at a distance.
Conservation Status
The Cave Swiftlet is currently assessed as Least Concern on the IUCN Red List. Its broad distribution and occurrence in a range of natural and modified habitats support this assessment, but local populations may still be affected by disturbance.
Potential pressures include the destruction or alteration of caves, limestone quarrying, intensive tourism, poorly managed nest collection, and the loss of insect-rich feeding habitat. Conservation measures should include protection of important caves and woodland, control of quarrying in sensitive karst areas, and sustainable management of any nest harvesting. The global population size and precise population trend are not stated here because a reliable current estimate was not verified.
Frequently Asked Questions
Where is the Cave Swiftlet found?
It is principally found in Indonesia, including Sumatra, Java, Bali and Lombok. Its exact range depends on the taxonomic treatment used for related island populations.
Does the Cave Swiftlet live inside caves all the time?
No. It uses caves and other sheltered structures for nesting and roosting, but spends much of the day flying outside to feed on airborne insects.
Can the Cave Swiftlet echolocate?
Current ornithological evidence does not support confirmed echolocation in the Cave Swiftlet. Several related swiftlets do echolocate, which has sometimes led to the ability being incorrectly attributed to this species.
What does the Cave Swiftlet eat?
It feeds mainly on small flying insects and other aerial invertebrates captured during flight.
Does it make edible bird’s nests?
Its saliva-based nest construction has contributed to confusion with commercially harvested swiftlets. However, not every saliva-nesting swiftlet produces nests of commercial value, and the Cave Swiftlet should not automatically be treated as an edible-nest species.
How can I identify one in the field?
Look for a small, dark, fast-flying bird with a short forked tail, especially over forest edges, open country and settlements. Identification is often difficult, so photographs, calls and local species knowledge are useful.
References
- IOC World Bird List
- IUCN Red List of Threatened Species
- Echolocation in Oilbirds and Swiftlets, peer-reviewed ornithological literature
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