The Indian swiftlet (Aerodramus unicolor) is a small, aerial insectivorous bird in the family Apodidae. It is native to the Indian subcontinent, including India, Pakistan, Bangladesh, Nepal, Bhutan, and Sri Lanka, and it inhabits a range of forested and urban environments where suitable nesting sites are available.
Taxonomy and systematics
- Kingdom: Animalia
- Phylum: Chordata
- Class: Aves
- Order: Apodiformes
- Family: Apodidae
- Genus: Aerodramus
- Species: A. unicolor
The species was first described by Thomas C. Jerdon in 1840. It is one of several swiftlet species within the genus Aerodramus, which are distinguished by their ability to navigate and roost in dark caves using echolocation.
Physical description
The Indian swiftlet measures approximately 10–12 cm in length, with a wingspan of about 20–25 cm. It has a uniformly dark brown plumage with a slightly glossy sheen, a short, slightly forked tail, and a blunt, slightly curved beak adapted for aerial capture of insects. The flight is rapid and agile, characterized by a humming sound produced by the wings.
Distribution and habitat
The species occurs throughout the Indian subcontinent, from the lowland plains to foothill regions up to roughly 1,200 m in elevation. It favors habitats that provide abundant aerial insects and suitable nesting sites, such as cliffs, caves, overhangs, and occasionally man‑made structures like bridges and buildings.
Behavior and ecology
- Feeding: The Indian swiftlet feeds almost exclusively on flying insects, including flies, mosquitoes, and small beetles, captured in flight. Foraging typically occurs at dusk and during the early night, when insects are abundant.
- Flight: It exhibits a swift, direct flight pattern with rapid wingbeats, enabling it to maneuver deftly in open air.
- Echolocation: Like other swiftlets, it employs simple ultrasonic clicks for orientation within dark roosting sites.
Breeding
The breeding season varies regionally but generally coincides with the pre‑monsoon and monsoon periods (April to September). Nests are constructed on vertical surfaces within caves or on sheltered rock faces, using saliva mixed with plant fibers and lichens to form a cup‑shaped structure. The clutch typically consists of one to three white eggs, which are incubated by both parents for 15–18 days. Fledging occurs approximately 20 days after hatching.
Conservation status
The International Union for Conservation of Nature (IUCN) currently lists the Indian swiftlet as Least Concern, owing to its relatively wide distribution and large population. However, localized threats include disturbance of nesting sites, habitat loss due to deforestation, and exploitation of edible‑nest swiftlet colonies for bird’s nest soup, although the Indian swiftlet is not a primary source of commercial nests.
Human interactions
While the Indian swiftlet is not a major source of edible nests, it sometimes roosts on buildings and bridges, leading to minor conflicts with humans due to droppings. Conversely, its presence can be beneficial for insect control in agricultural and urban settings.
References
- BirdLife International. (2023). Aerodramus unicolor. The IUCN Red List of Threatened Species.
- Jerdon, T. C. (1840). A Catalogue of the Birds of the Peninsula of India. Madras.
- Chantler, P., & Driessens, G. (1995). Swifts: A Guide to the Swifts and Treeswifts of the World. Pica Press.
