Seychelles Swiftlet: where and when to see them

The Seychelles swiftlet is a small, dark aerial insectivore endemic to the granitic Seychelles. It spends much of its active life flying above forest, clearings and slopes, but depends on sheltered caves for roosting and nesting. Its plain plumage can make identification challenging at a distance. The species' restricted distribution and reliance on relatively few breeding sites mean that disturbance or deterioration at a cave can have disproportionate consequences.

Size

10–12 cm long

Weight

Not reliably established

Lifespan

Not reliably established

Status

Vulnerable

Swiftlets forage in loose groups, repeatedly crossing productive patches of air where insects accumulate. Their flight alternates rapid wingbeats with glides, and they can travel between feeding areas as weather changes. In dark nesting chambers they use audible echolocation clicks to help navigate. Colonies attach small nests to cave surfaces. Visitors should observe birds in open air rather than approaching colony entrances or attempting to follow returning birds inside. Swiftlet colonies can be quite large, with hundreds of individuals using the same nesting cave. They are highly social, especially during foraging and roosting, often forming large mixed-species flocks with other aerial insectivores. The use of echolocation for navigation within dark caves is a remarkable adaptation, unique among most birds.

• It can navigate dark nesting areas using echolocation clicks.
• Its genus includes other cave-nesting swiftlets across the Indian and Pacific oceans.
• The nest combines plant material with saliva used as a binding agent.
• Unlike many small birds, it captures nearly all its food in flight.

Resident swiftlets may be seen in suitable airspace year-round. Fair weather with active flying insects generally offers easier observation than heavy rain or strong wind. Intermonsoon travel periods can be convenient, but they should not be treated as a confirmed peak in nesting or abundance. While present year-round, breeding activity typically peaks during the drier months, which can offer more consistent observation conditions. Prolonged dry spells can reduce insect availability, influencing foraging patterns and energy expenditure. Consider the local weather forecast for each island, as conditions can vary even within the archipelago.

Forested hills, valleys, clearings and some coastal airspace provide feeding opportunities. Suitable caves and sheltered rock chambers are essential for colonies, linking breeding habitat to the broader landscape. A bird passing over a beach may be feeding well away from its nesting site. This endemic species is restricted to the granitic Inner Islands of the Seychelles, primarily Mahé, Praslin, La Digue, and Silhouette. Optimal habitat often includes a mosaic of native forest and open areas, allowing access to both food sources and nesting sites. Its presence is directly tied to the availability of suitable large cave systems for breeding.

It catches small airborne insects and other tiny flying arthropods on the wing. Prey availability changes with rainfall, wind and local vegetation. Rather than hunting individual large prey from a perch, swiftlets continuously search the air and exploit concentrations of small insects. Swiftlets are aerial insectivores, consuming a wide variety of small arthropods including flies, beetles, and hymenopterans. They are efficient foragers, often concentrating their feeding activity at specific altitudes where insect densities are highest. Their flexible foraging strategies allow them to exploit ephemeral insect blooms across different microclimates.

Common name

Seychelles Swiftlet

Scientific name

Aerodramus elaphrus

Animal group

Birds

Size

10–12 cm long

Weight

Not reliably established

Lifespan

Not reliably established

Status

Vulnerable

Identification

Its small, uniformly dusky body and short, shallowly forked tail differ from the contrasting underparts and longer tail streamers of visiting barn swallows. Note the fast, flickering wingbeats interspersed with short glides, a typical swiftlet flight signature. Unlike most swallows, swiftlets do not typically perch in the open and are almost exclusively seen in flight. Their dark plumage lacks any significant markings or iridescence, appearing uniformly somber in most lighting conditions.