Swift or Swallow: How To Tell The Difference?

Swifts (Apus apus) and Swallows (Hirundo rustica) are two iconic signs of the arrival of summer in British skies, signalling the start of warmer weather and longer daylight hours. Fast-flying aerial birds, swifts and swallows may be hard to distinguish from the ground, but on closer inspection are two very different birds both in appearance and behaviour. So what are the key differences between these two high-altitude summer visitors?

One way to tell the difference between a swift and a swallow when looking up at the sky is its silhouette. Swifts have scythe-shaped wings, and a slightly blunt forked tail, while swallows have a much longer, trailing forked tail and more rounded wings.

Plumage is also key, but it is rare to be near enough to a swift to get even the briefest glimpse of its feathers up close. You may see swallows resting briefly on telephone wires in the countryside, and spot the shimmer of blue back and wing feathers, and the bright red-orange throat. Swifts are a deep shade of brown all over, with some white facial markings.

These are two quick ways to distinguish between swallows and swifts, but not the only way to learn to tell them apart, so keep reading to learn how to confidently and accurately identify these two acrobatic fliers with ease.

Common Swift

Barn Swallow

Which is bigger, a swift or a swallow?

From the ground, looking up at the sky, it’s hard to work out which is bigger – a swift or a swallow.

In length and weight the two birds are roughly the same size, with swallows being slightly longer and swifts weighing fractionally more. Where the key difference lies, however, is wingspan. A swift’s elongated crescent-shaped wings are around double the length of those of a swallow. Swallows’ tails are longer, which adds to their overall body length.

Swallow measurements

• On average, swallows have lengths between 17 and 19 cm (6.7 and 7.5 in)
• Swallows weigh between 32 and 35 grams (1.1 and 1.2 oz)
• Swallows’ wingspans vary between 16 and 25 cm (6.3 and 9.8 in)

Swift measurements

• Swifts are on average between 16 and 17 cm (6.3 to 6.7 in) in length
• Swifts weigh between 36 and 50 grams (1.3 to 1.8 oz)
• Swifts’ wingspans range between 42 and 48 cm (16.5 and 18.9 in)

A perched Swift

Which is more common, swifts or swallows?

There are 860,000 breeding territories of swallows in the UK, but only 59,000 breeding pairs of swifts. Swifts are classed as a globally threatened species, classified Red (the highest level of conservation priority) on the 2021 UK Conservation Status Report.

In the UK, you're much more likely to see a swallow than a swift.

Other differences between swifts and swallows

Although both are aerial birds, swifts fly at far higher altitudes than swallows and are capable of much faster speeds. Swallows fly far closer to the ground, and can be seen skimming over the surfaces of lakes to catch insects to eat.

They can reach a maximum speed of 35 mph. It’s not unusual to see a swallow perching briefly on a fence, telephone wire, or barn roof, before swooping low to pluck insects from the air or pick up wet mud for nest construction.

Swifts fly much higher in the sky, soaring at speeds of up to 69 mph and never coming to land. They feed, sleep, and even mate on the wing.

Their feet are not adapted for walking, and only have short legs, which they sometimes use to cling to a vertical wall surface when entering a nest site, but will never come to land unless injured or in distress.

Perched Barn Swallow

Feeding

Both swifts and swallows feed on the wing, and exclusively on insects, although how they catch them is slightly different. Swallows feed near the ground, swooping to catch insects near or on the surface of lakes or over open pastures and meadows. They skim the surfaces of lakes, scooping up water to drink with their beaks.

Swifts feed on flying insects and airborne spiders at altitudes of between 50 and 100 m (160 to 330 ft), although in warmer weather insects will be present at even higher heights. Swifts drink by catching raindrops in flight, but will also occasionally swoop to drink from lake surfaces in the same way as swallows in colder weather.

Swift in flight

Nesting

Swallows construct messy cup-shaped nests from wet mud, inside the eaves of barns or disused farm buildings. In contrast, swifts barely use any nesting materials, and prefer to nest in holes or cavities in buildings, or in specially designed swift nest boxes and purpose-built ‘swift bricks’ found in the walls of some modern houses.

Migration

Both swallows and swifts are migratory birds, but have slightly different annual schedules when it comes to making their summer and winter journeys to and from Africa. Swallows arrive first, from March onwards, and are present in the UK until October.

The first swifts are usually seen from mid-April onwards, and depart in August once their young are capable of longer, sustained flight.

Swallows that breed in the British Isles spend winters in South Africa, migrating to the UK over the Sahara, Morocco, Spain and western France.

Swifts do not typically travel as far south into Africa as swallows on their annual migrations, tending to spend winters in Equatorial and Sub-Saharan regions.

The courtship display of a Barn Swallow

Range

Swallows are more common and widespread in the UK than swifts. Swifts breed throughout the UK, but populations are mainly concentrated in the south and east of England. Swallows are widespread summer visitors to the whole of the UK, except a couple of small areas in the extreme Scottish Highlands.

You’re more likely to see a swift in urban areas, while swallows are typically found in rural landscapes, near to water.

Sounds and calls

• Swifts have a very distinctive piercing high-pitched call, and can be heard screeching overhead often before they come into view.
• Swallows have a more tuneful repertoire of calls, with chirping and a twitter-warble song, often heard when perching.

Close up of a Common Swift

Plumage

Up close, swifts and swallows are visually very different. Male and female swifts are very similar in appearance, with a dark, sooty-brown plumage, a black beak, and some white markings on the throat and face.



Male swallows have glossy blue backs, wings, and tails. Their faces and throats are rusty red-orange, separated from their off-white underparts by a band of blue.

Close up of a Barn Swallow

Female Swift vs Female Swallow

Female and male swifts are very similar in appearance, with one minor difference being the brightness of the pale facial feathers. Male swifts have slightly whiter chin and throat markings than those of females.

Female swallows are similar to males in shape, size and colour, but have shorter tail streamers, and are generally less glossy. Their faces and throats are a more muted shade of red-orange, and their underparts are paler.

Juvenile Swift vs Juvenile Swallow

Juvenile swifts are a deeper shade of brown-black than adults, and have a pale ‘eyebrow’ marking on their face. Young swifts fledge between 35 and 56 days after hatching.

Juvenile swallows are a more mottled shade of brown-blue, and lack the long trailing tail streamers of adult birds. Baby swallows are ready to leave the nest significantly sooner than young swifts, with fledging taking place between 17 and 24 days.