Birds

Swallow

Hirundinidae · also called swallows, martins

Least Concern ↓ insectivore Temperate grassland Coasts & shorelines Rivers & wetlands

A swallow spends its life in the air over open country, scooping up flying insects in fast, swooping passes, and for thousands of years its return each spring has been the signal that winter is over. The bird that skims a European meadow in May has just flown up from southern Africa to be there.

Overview

Swallows and martins are the family Hirundinidae, about 90 species of small, long-winged, aerial insect hunters on every continent but Antarctica. They have a wide gape for catching insects in flight, tiny weak legs, and in many species a deeply forked tail with long streamers.

Mud nests and long journeys

Barn swallows and house martins build a cup of mud pellets — hundreds of beakfuls — stuck under an overhang, while cliff swallows make enclosed gourds and some species dig burrows in sandy banks. The barn swallow now nests almost exclusively on human structures, and it is an extreme migrant: Northern Hemisphere breeders winter in the tropics, some flying 10,000+ km each way.

Ornament and omen

A male barn swallow’s tail streamers are longer than flight efficiency alone would favour — females prefer the longest, so the tail is partly a display of quality. And swallows really do fly low before rain, following insects that stay near the ground in humid, low-pressure air.

Status

Least Concern as a family, but declining — aerial insectivores have fallen across Europe and North America, likely from fewer flying insects, lost nest sites in modernised farm buildings, and pressures on migration. A few tiny-range species, like the possibly-extinct white-eyed river martin, are gravely threatened.

Swallow: common questions

What is the difference between a swallow and a swift?

They look alike in flight and both catch insects on the wing, but they are not related, swallows being songbirds and swifts being closer to hummingbirds. A swallow has a forked tail, often with long streamers, broad-based triangular wings, a fluttering, swooping flight with frequent glides, and it perches readily on wires and lands to collect mud. A swift has a short tail, very long narrow scythe-shaped wings, a stiff, fast, flickering flight, and it essentially never perches, spending almost its entire life airborne. Swifts also scream in fast-flying groups around rooftops, which swallows do not.

Where do swallows go in winter?

The migratory swallows leave their breeding grounds in autumn and fly to the tropics. European barn swallows winter in sub-Saharan Africa, mostly in the south, North American barn swallows winter in Central and South America, and East Asian birds move to Southeast Asia and Australia. These are long, demanding journeys of several thousand kilometres, made in stages with stops to feed, and a bird may return to the exact same barn or ledge to breed the following spring. Before migration was understood, people believed swallows hibernated in mud at the bottom of ponds.

Are swallows and house martins the same thing?

They are close relatives in the same family, and the names overlap confusingly between regions. In British usage the swallow is the barn swallow, a bird with a long forked streamer tail and a dark red throat that nests on beams inside buildings, while the house martin is a smaller, shorter-tailed bird with a white rump that builds an enclosed mud nest under the eaves outside. In North America, martin usually means the purple martin, a large swallow that nests colonially in boxes. All are hirundines, and all catch insects in flight.

Why do swallows fly low before rain?

It is a real pattern with a simple cause. Swallows follow their insect prey, and in humid, low-pressure air ahead of a weather front many flying insects stay closer to the ground, partly because damp air makes flight harder for them and partly because the plants and warm ground near the surface hold more of them. The swallows drop down to feed where the insects are. In settled high-pressure weather, insects and swallows rise higher. So low-flying swallows genuinely do tend to precede rain, which is why they feature in weather lore.

Sources & further reading

Written by HideShark Editorial Team · reviewed by HideShark Science Desk. Published September 11, 2026. Last updated September 11, 2026.

Quick facts

Scientific name: Hirundinidae
Diet: Almost entirely flying insects caught in mid-air, including flies, midges, aphids, flying ants, beetles, and moths, hunted low over grassland, water, and livestock in fast, swooping flight, with a swallow taking many thousands of insects a day when feeding young
The family: Swallows and martins are the family Hirundinidae, about 90 species worldwide, small birds with long pointed wings, a short bill and wide gape for catching insects, small weak legs, and, in many species, a deeply forked tail with long outer streamers
Long-distance migrants: Many swallows are extreme migrants, and the barn swallow, the most widespread, breeds across the Northern Hemisphere and winters in southern Africa, southern Asia, and South America, some individuals flying more than 10,000 kilometres each way twice a year
Mud architects: Barn swallows and house martins build a nest cup from hundreds of beakfuls of mud pellets, mixed with grass and saliva and stuck to a wall, beam, or cliff under an overhang, while cliff swallows build enclosed gourd-shaped mud nests in dense colonies and other species dig burrows in sandy banks
Tied to people: The barn swallow has nested on and in human structures for so long that it is now almost never found nesting anywhere else, and its spread followed the spread of farms and buildings, making it one of the birds most closely bound to human landscapes
One swallow, no summer: The proverb that one swallow does not make a summer goes back to Aristotle, and across Europe the arrival of the first swallows has marked the start of spring for thousands of years, tracked in folklore, weather lore, and record-keeping
Streamers for show: The long tail streamers of a male barn swallow are longer than aerodynamics alone would favour, and females prefer males with longer, more symmetrical streamers, so the tail is partly a sexually selected ornament that signals a male's quality
Range: Every continent except Antarctica, breeding from the tropics to the edge of the Arctic, in open and semi-open country including farmland, grassland, marshes, lake and river margins, coasts, and towns, and wintering, for the migratory species, mainly in the tropics, with the greatest variety of resident species in Africa.
Conservation status: Least Concern ↓ ≈ Most swallows are widespread and common, and the family as a whole is not threatened, but a number of species are declining, and aerial insectivores as a group have fallen across Europe and North America over recent decades. The causes are thought to include the loss of flying-insect abundance from pesticide use and intensive farming, changes in agriculture that reduce nesting sites and cattle-associated insects, the modernisation and sealing of barns and outbuildings, and conditions on the wintering grounds and along migration routes. A few species with tiny ranges, such as the white-eyed river martin, known from a handful of records and possibly extinct, and the Bahama swallow, are seriously threatened in the wild