Do Swifts Ever Land? Ten Months in the Air Explained

How long do swifts stay in the air?

The common swift spends about three months a year at its nest. The other nine to ten months, from the end of the breeding season in July or August until it comes back the next April or May, are spent flying: south across Europe, over the Sahara, around Africa in winter and back again.

For a long time this was only a strong suspicion based on observations. Birdwatchers in Africa almost never saw swifts perched or roosting, and swifts were known to spend summer nights high in the sky. In 2016, researchers at Lund University in Sweden published the first direct evidence. They fitted swifts with tiny data loggers that recorded flight activity and light levels and retrieved them when the birds came back to their colonies a year later.

The results were striking. Some of the swifts stayed in flight for the entire ten-month non-breeding period, with no sign that they ever landed. Others settled for short spells, probably on nights of bad weather, but even these birds spent more than 99 percent of the time flying. No other bird is known to stay in the air for so long.

How do swifts eat and drink in flight?

A swift’s whole way of life is built for the air. It feeds only on flying insects and on tiny spiders drifting on silk threads, which it catches in its wide mouth while flying. There is no need to land to eat, because its food is in the sky.

To drink, swifts swoop low over lakes and rivers and skim water from the surface with their bills, or catch falling raindrops. They also bathe by flying through rain. Collecting nesting material happens in the air too: feathers, seeds with fluffy parachutes and bits of plant fluff are snatched as they float past.

Mating in flight has been observed, although most pairs mate at the nest. The only things a swift cannot do on the wing are lay eggs and raise chicks.

Do swifts sleep while flying?

Swifts almost certainly sleep in the air, but scientists have not yet been able to record their brain activity in flight, so the details are not proven. What is known is that at dusk swifts climb steeply, often to heights of a couple of kilometers, and then glide slowly downward through the night, flapping only now and then. This slow, energy-saving flight is the most likely time for sleep.

Evidence from another bird supports the idea. In 2016, scientists recorded the brain waves of great frigatebirds flying over the ocean for days at a time. The birds slept in flight in very short episodes, often with only one half of the brain asleep while the other half stayed alert, adding up to well under an hour of sleep per day. Swifts may use a similar strategy, but this still needs to be tested.

Why are swift legs so small?

Swift legs are tiny, and the scientific name of the family, Apodidae, means “without feet”. The legs are not useless, however. Each foot has four short toes that can all point forward, ending in strong, curved claws. They are designed for gripping the rough inside of a nest hole or clinging to a vertical wall, not for walking or perching on a twig.

Having small legs saves weight and drag, which matters for a bird that flies hundreds of thousands of kilometers a year. The trade-off is that swifts are clumsy on flat ground. Their long wings make it hard to get airborne from a level surface, so they normally take off by dropping out of a high nest entrance. A swift found on the ground is usually in trouble.

Do young swifts land before they breed?

This is one of the great open questions about swifts. A young swift leaves the nest on its first flight, independent of its parents, and many head to Africa almost at once. Most swifts do not breed until they are about four years old, although some start at two or three.

If young birds never land before they first nest, they could stay airborne for two, three or even four years. Many experts think this is likely, but it has not yet been confirmed by tracking, because the loggers have to be recovered from birds returning to a nest. Some one-year-old swifts stay in Africa for their first summer, and non-breeding birds that do return to Europe visit colonies, scream around the roofs and prospect for nest holes, but they spend the nights in the air.

Other birds that stay airborne for months

The common swift is not the only bird that lives mostly in the air:

• Alpine swift: in 2013, trackers showed that alpine swifts breeding in Switzerland stayed in flight for more than 200 days in a row during migration and the winter in West Africa.
• Frigatebirds: these seabirds cannot swim or take off easily from water, so they stay aloft over the ocean for weeks at a time, riding rising air under clouds.
• Other swifts: pallid and white-rumped swifts, and many tropical swifts, are also highly aerial, though they have been studied less.

Swallows and martins, which look similar, are quite different in this respect. They perch on wires and branches and roost at night in reedbeds or nests. Our swallow vs swift guide explains how to tell them apart.

Why do swifts stay in the air?

Staying aloft makes sense for a bird that eats only flying insects. Every landing costs energy, because taking off again is hard for a swift, and the ground is where predators wait. In the air, a swift can follow weather systems, move to places where insects are swarming and avoid cold spells, all without stopping.

This way of life also explains why swifts fly so efficiently. They glide a lot, use thermals and winds, and can reach high speeds when needed, as shown in how fast can a swift fly?. You can read more about the bird’s appearance, breeding and migration in our common swift profile.