Black Swift

How to find it

Watch the sky over mountain cliffs and waterfalls, since nests are usually near or behind falling water. That water is loud, which makes the birds hard to hear at breeding sites, so rely on your eyes. At colonies the birds are most vocal at dawn and dusk, when they leave or return to the nests. Keep an eye on the leading edge of an approaching rainstorm, where it often feeds with other swifts. Scan high, because it often hunts far above the ground.

How to recognise it

In flight it looks like a flying cigar, with long, slender, curved wings and a short, slightly forked tail. It is mostly sooty dark gray.

The shoulders are clearly darker than the rest of the wing, and the inner and outer wing show some contrast.

Adults are black with a bluish gloss above and paler, grayer underparts. There is whitish scaling on the forehead. The bill and feet are black, and length is about 18 cm.

The Costa Rican subspecies is darker than the northern borealis form and mid-sized between the northern and Caribbean forms. Males have a grayer head and neck than Caribbean birds.

Behaviour and diet

The Black Swift catches flying insects in the air, often very high up. In Costa Rica it often feeds with other swifts along the leading edge of rainstorms. Prey includes winged ants, bees, wasps, flies and beetles, and it lives in groups.

Its wings are long and its legs very short, so it almost never lands on the ground. It feeds in flight and only perches for long periods when nesting on cliffs.

Where it lives

The Costa Rican subspecies breeds in the Costa Rican highlands, and the first specimen came from the San José area. The Costa Rican race breeds in the central highlands, and possibly in western Panama as well.

Across its range it nests in colonies on ledges of steep rock faces, usually near or behind waterfalls. Nest sites are scattered and hard to reach.

When to see it

The Costa Rican form is a summer resident from April to October. Flocks are sometimes seen moving north between Costa Rica and southern Mexico in March and April.

Similar birds

Black Swift and Chestnut-collared Swift can look almost identical, even with long, good views. Their voices separate them right away. That comes from fieldwork in Mexico, not Costa Rica, but it is a useful reminder to listen as well as look.

Names and lore in Costa Rica

The Costa Rican Spanish name is Vencejo Negro, and some lists give the Costa Rican subspecies its own name, Vencejo Negro de Costa Rica. Its habit of flying very high gave it old English names such as cloud swift, and a myth said it spent the winter hibernating in the clouds.

Status and conservation

The AOCR list marks it as R,M, a resident and migrant, and BirdLife International lists the species as Vulnerable across its whole range.