Common Swift

The Common Swift is a master of aerial life, so committed to flight that it eats, sleeps, and even mates on the wing, only landing to nest. It appears almost entirely sooty-black at a distance, with a slightly paler throat visible at close range, a short forked tail, and long, narrow, curved wings that give it a distinctive anchor or boomerang silhouette in flight.

Swifts are unrelated to swallows and martins despite superficial similarity; their closest relatives are hummingbirds. Parties of screaming swifts racing low around buildings on summer evenings are one of the most familiar sounds of the northern hemisphere skies.

Key field marks

• All-dark sooty-brown plumage, appearing black in flight, with a small pale throat patch
• Long, narrow, sickle-shaped wings and a short, shallowly forked tail
• Extremely fast, stiff-winged flight with bursts of rapid beats and long glides
• Never perches on wires or the ground; only lands to enter a nest cavity

Similar species

Swallows and martins have more fluttering flight, forked tails often with white markings, and pale underparts; swifts are uniformly dark and fly with stiffer, more scything wingbeats. The larger Alpine Swift shows a white belly and throat separated by a brown breast band.

Range

Breeds across Europe, North Africa, and much of temperate Asia; winters in sub-Saharan Africa.

Habitat

Forages over almost any open habitat -- towns, farmland, wetlands, and mountains -- wherever flying insects are abundant. Nests almost exclusively in cavities in buildings (under roof tiles, in eaves) or, historically, in cliffs and old trees.

Migration

A long-distance migrant, wintering in Africa; remarkably, non-breeding immature swifts may remain continuously airborne for months at a time, including through the night, without landing.

Behavior

Almost entirely aerial, swifts feed, drink, collect nesting material, and even sleep on the wing, descending only to nest. Parties gather in fast, screaming chases around nest sites at dusk, known as "screaming parties."

Voice

A loud, shrill screaming call given in flight, especially during social chases around nesting colonies; largely silent away from the nest site.

Feeding

Catches flying insects and airborne spiders in its wide gape while in continuous flight, often foraging at considerable heights or ranging many kilometers from the nest.

Nesting and breeding

Nests in cavities in buildings, laying 2-3 eggs on a small pad of feathers and airborne debris glued together with saliva. Both parents incubate and feed the young, which can survive short periods of starvation by entering a state of torpor during cold, insect-poor weather.