Swifts flying over rooftops

About swifts

The swift is one of the last summer migrants to arrive in the UK and the first to leave. 'Screaming' calls reveal the presence of parties of swifts flying above towns.

A life on the wing

Studies of swifts have revealed some startling facts – particularly their ability to fly long distances.

It's estimated that swifts fly an average daily total of 800km – nearly 500 miles. That's about 2 million km (more than 1.24 million miles) in a lifetime. Swifts spend their life almost entirely on the wing and even feed, sleep and mate in flight. They feed exclusively on insects and only come to land when nesting.

They hunt for insects over a range of habitats from meadows, open water and over woods, to the skies above towns and cities.

An abundant supply of insects is critical for their survival. Parent swifts collect lots of insects to take back to their chicks – up to 1,000 at once, which make a big bulge in their throat. When they have chicks to feed, swifts can gather as many as 100,000 insects a day.

'Our' swifts fly across the Sahara desert in autumn and some even go as far south as South Africa. Others don't go quite as far and stay around central Africa. It's a long journey but they don't hang around: one young bird left its nest in Oxford and flew all the way to Madrid in just three days.

As a group, swifts are the fastest birds in level flight. The peregrine is officially the fastest bird but only in a steep dive called a stoop. Our swift holds the record for the fastest proven flight, recording an impressive top speed of 69.3mph in a recent study. The needle-tailed swift of Africa and Asia has been reported to reach over 100mph but this is yet to be officially proven.

Good neighbours

Sharing your house with swifts is a great privilege. They are unobtrusive when nesting and make perfect, quiet neighbours. 

Previously more commonly found nesting in cliffs and caves, swifts make use of roof spaces in buildings where they construct a simple nest. These can be hard to locate because swifts enter and leave quietly through a narrow opening (usually measuring 25–35mm by 60–70mm) and leave few, if any, droppings below the entrance.

Swifts incubate their eggs for between 19 and 25 days. For a bird that's used to flying all the time, it must be difficult for them to keep still for so long. So, to keep in shape, they perform 'press-ups' using their wings.

Common swift Apus apus, individual clinging on to door, this bird was being rehabilitated to eventually be released, Bedfordshire, England,

Why swifts are amazing

Here are our top reasons why they're so fantastic:

  • After leaving the nest where they hatched, they'll keep flying non-stop for three years!
  • They even eat, mate and sleep in the air - they can 'snooze' with one side of their brain at once, and then switch to the other side
  • Some of 'our' swifts migrate as far as South Africa for winter
  • Parent swifts gather insect snacks for their chicks, carrying as many as 1,000 at once. Gulp!
  • Swifts like to live in our houses and churches - they squeeze through tiny gaps to nest inside roofs.
  • At dusk, groups of swifts fly around at high speeds, screaming.
 Common swift Apus apus, birds flying over rooftops of terrace houses, Luton, Bedfordshire, England

Identification

Swifts can be confused with three similar but unrelated species: the swallow, house martin and sand martin.

In built-up areas, the house martin is the species commonly confused with swifts.

Find out what we are doing for our other migrant species and how you can help on our Birds without Borders pages.