Common Swift

Voice

A piercing high scream, srreee, often given in chorus by parties racing low between buildings at dusk. Heard around colonies from late April to early August; outside those months the species has left Europe altogether.

Identification

Stiff, scythe-shaped wings, a short forked tail and uniform sooty brown plumage that looks black against the sky. In good light a pale throat patch shows. Flight is fast and flickering, with long glides and sudden banking turns; juveniles have pale feather fringes and a more obvious whitish throat.

Confusion species

House and Barn Martins are smaller, pale below and flutter more. Among swifts, Pallid Swift is the real problem: browner, with a stronger head and throat pattern, broader-based wings and a disyllabic scream. Rare in the Netherlands, common in southern Spain. Alpine Swift is far bigger and has a white belly.

Habitat

Nests almost exclusively in buildings — under roof tiles, in cavity walls, behind fascia boards and in nest boxes, above all in older town centres and village cores. Feeds high over towns, lakes and open country, dropping to low levels over water in wet weather.

Range and movements

Breeds across nearly all of Europe, from Iberia to beyond the Arctic Circle, and in every Dutch town with older housing. Winters in tropical and southern Africa; migration is rapid, so the birds vanish strikingly abruptly in August. In Spain it is as numerous in villages as in the cities.

• Breeding (summer)
• Passage
• Migration direction
• dark = core range, pale = thinly spread

Where and when to look

Stand in an old quarter on a warm June evening, an hour before sunset: that is when the screaming parties form and tear along the housefronts. In muggy, thundery weather also watch for high flocks streaming away ahead of a front.

Conservation status

Declining across much of western Europe. The main cause is loss of nest sites: renovation, cavity insulation and new building seal off the spaces under roofs. Falling numbers of aerial insects add to the pressure. Nest bricks and keeping existing holes during building work demonstrably help.