Head to head
Common Swift vs Barn Swallow
Swifts and swallows share the summer sky over towns and farmland, both catching insects in fast flight, and they are endlessly confused. But they are not close relatives at all. The swift is more closely related to hummingbirds, while the swallow is a songbird, and their resemblance is a case of two very different birds solving the same problem in a similar way.
| Common Swift | Barn Swallow | |
|---|---|---|
| Family | Swifts, related to hummingbirds | A songbird, in the swallow and martin family |
| Perches? | No; it cannot perch and lands only at the nest | Yes; sits readily on wires and twigs |
| Plumage | Uniform sooty brown-black, pale throat patch | Glossy blue back, red face, pale belly |
| Tail | Short, shallow fork | Deeply forked with long streamers |
| Wings | Long, stiff, scythe-shaped | Pointed but broader and more flexible |
| Nest | A shallow scrape in a high crevice or cavity | An open mud cup on a beam or ledge |
| Voice | A high, screaming screeee from flying parties | A soft, chattering, twittering song |
| Time in Europe | About 3 months, roughly May to early August | About 6 months, roughly April to September |
Swift vs Swallow: common questions
How can I quickly tell a swift from a swallow?
Colour and behaviour do it fastest. A swift looks all dark, almost black against the sky, with long stiff curved wings held out like a crescent or an anchor, and it flies fast and high in screaming groups, never stopping and never perching. A swallow looks two-toned, dark blue above and pale below with a red throat, has a deeply forked tail with fine streamers, and flies lower with more twisting, fluttering turns, often over water and pasture, and it perches on wires and buildings. If you see a bird sitting on a telephone wire it is a swallow or a martin, never a swift. If you see a screaming party of dark birds racing around a rooftop in high summer, those are swifts.
Is it true a swift never lands?
Almost. Once a young common swift leaves its nest it becomes airborne and typically does not land again until it is old enough to breed, two or three years later, when it finally comes down to a nest site of its own. In between it does everything in the air. Tracking studies have confirmed that swifts on their non-breeding grounds in Africa can stay aloft continuously for months, and they sleep on the wing by climbing to altitude at dusk and dozing while gliding, shutting down one half of the brain at a time. Even breeding adults only enter the nest crevice and otherwise remain flying. A swift found on the ground is usually a grounded bird in trouble, because its long wings and tiny legs make taking off from a flat surface very hard.
Why are swifts and swallows both declining?
They face overlapping pressures. Both feed entirely on flying insects, and the widespread fall in insect numbers, driven by pesticide use and intensive farming, reduces their food, especially the aerial plankton of small flies and aphids they rely on. Both also depend on specific nest sites that modern building has removed, with swifts losing access to roof cavities and gaps under eaves as houses are renovated and sealed, and swallows losing the open barns, sheds, and outbuildings they nest in as these are converted or demolished. Cold, wet weather in the breeding season can wipe out broods of either species, and both run a gauntlet of drought, storms, and habitat loss on migration and in Africa. Nest bricks, swift boxes, and leaving access to outbuildings all help.