Swift, Swallow Or Martin? How To Swiftly Tell The Difference

Summer Is Coming. It really is. Even if the weather has been all over the place lately. But give it another two months, and it will be, to quote DJ Jazzy Jeff & The Fresh Prince, summer, summer, summertime. And summertime brings baby swallows, swifts and martins. You can already start seeing these tippy tail-birds all over the skies from April onwards, gobbling up mozzies and flies along the way. Being highly aerial, these birds eat and drink during flight, and even bathe, mate, and sleep on the wing!

Swifts flying in the sky

Mysterious Flyers 
(© Maxvandaag.nl)

Keep ‘Em Coming

Because these aerial high-flyers are so busy up there, we don’t get to see all that much of their actions. And unfortunately, we will be seeing even less of them, as they are in some serious trouble. House martin, swallow and swift populations are rapidly declining. Swift numbers alone have halved in just the past 20 years. The main causes:

  • Insecticides used in farming: have you noticed how few insects we have buzzing about these days? Their numbers are massively reduced, which means the birds’ food source is also getting smaller and smaller.   
  • The loss of suitable nesting sites: these birds like to nest on beams, under the eaves of buildings, and in deep cavities such as holes around pipework, missing bricks etc., but the disappearance of old houses (and previous nest sites to return to), along with people’s negative attitudes towards birds nesting on their property, and modern construction which tends to seal buildings tightly, leaves no space for new nests.
  • Climate change affects our birds, too: it creates cold and wet summers, overwintering sites abroad are changing, and migration routes are becoming more difficult.

Making you feel sombre and powerless? Chin up, you can help! Besides doing your everyday bit to fight climate change including opting for insecticide-free foods, you can help these feisty flyers by creating nesting sites for them. There is a wonderful, highly detailed article on making swift homes, available on Swift-conservation.org.

Another very handy guide can be found here - it provides tips specifically adapted to housing either common swifts, barn swallows, or house martins, as they each have their own nesting preference, from eaves to beams.

Placing a swift box - © www.vogelbescherming.nl

Placing a Swift Box
(© Vogelbescherming.nl

Cavity-loving Shy Swift © www.vogelbescherming.nl

Cavity-loving Shy Swift

Identifying Fast Flyers

All eaves aside, how do you, first of all, know which bird is actually which? They sure look alike and are quite similar in behaviour. There are some clear differences however, so you can tell them apart no matter how swiftly they swoop by. We’ve winged through several great birding sources and flocked as many details together as we could, from beaks to babas. Below, you will find their main characteristics listed, which should help you identify them in the blink of an eye and the flutter of a wing. The more we know about them, the better we can help them find a suitable nest site, whether self-built or store-bought, and survive on this beautiful planet we all share and can welcome as one home.  

Swift Sharing Home © www.vogelbescherming.nl

Swift Sharing Home 
(© Vogelbescherming.nl)   

(Common) Swifts

Common Swift © Mike Langman (rspb-images.com)

Common Swift
(© Mike Langman (rspb-images.com))


Dark all over, with lighter throat
Sooty brown - can appear black in the sky
Black beak
Black-brown legs


Forked (less forked than a swallow’s tail)






Length: 16-17 cm
Wingspan: 42-48 cm
Weight: 36-50 g


A harsh, piercing screaming:
© Jean Roché, Sittelle.com (Garden-birds.co.uk)


Winter habitat: Africa
Visit Britain between late April and September
Natural habitats: farmland, grassland, urban and suburban, wetland

Often found in parties, swooping low and fast around buildings, screaming and chasing one another all day long - but luckily not noisy at the nest

Swifts pair for life, meeting up in the spring at the same nest site
Nest in colonies
Nests are hidden in cavities in buildings - under eaves and in holes in the wall
Breeding is the only time they stop flying
Male and female both feed the young and take turns incubating the eggs


Eggs: white, smooth, matt, 25 mm by 16 mm

Juveniles: have a pale eyebrow


Flying insects and airborne spiders, avoiding stinging insects

When it is warm, insects will be carried higher in the air causing the swifts to fly at higher altitudes (on average around 50-100m, though sometimes as high as 1000m), and nearer to the ground when it is colder

In rough weather, they will feed over water where more insects can be found

Drink water by catching raindrops in the air or flying low over water, skimming from the surface


Swifts are larger than swallows

Slim, tapering body

Wings appear crescent/scythe-like during flight

Relative to their body size, they have the shortest legs of all birds, and can’t take off from the ground, which is why they need to take off from a good height, and you won’t find them perched on a wire or fence; they can hardly walk! If you spot an uninjured swift on the ground, place it on your hand with the bird facing forwards, and slowly raise your arm up and down to encourage it to take off

Common Swift, Help When Found on the Ground Without Obvious Injuries - © http://blascozumeta.com

Common Swift, Help When Found On Ground Without Obvious Injuries 
(© Blascozumeta.com

Common Swift Nest © www.swift-conservation.org

Common Swift Nest
(© Swift-conservation.org)

  • Breeding starts: Late May
  • Clutches: 1
  • Eggs: 2-4
  • Incubation: 19-20 days
  • Fledge: 35-56 days
Common Swift In Flight © Keta Detail of Apus_apus_flock_flying.jpg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2817682

Common Swift In Flight
(© Keta Detail of Apus_apus_flock_flying.jpg, CC BY-SA 3.0,

(Barn) Swallows

Barn Swallow © Mike Langman (rspb-images.com)

Barn Swallow
(© Mike Langman (rspb-images.com))


Red throat, chin and forehead
Off-white belly
Glossy blue upper-parts
White markings along inside edges of tail fork
Black beak
Black-brown legs


Distinctly forked
Long tail streamers






Length: 17-19 cm
Wingspan: 32-25 cm
Weight: 16-25 g


A quavery mix of trills and twitters, similar to the sparrow’s ramble:
© Jean Roché, Sittelle.com (Garden-birds.co.uk)


Winter habitat: southern Africa
Visit Britain between late March and October
Natural habitats: farmland, grassland, upland, urban and suburban, wetland

Often circling gracefully overhead, or swooping low over water and ground. Swallows fly low when rain is on the way, and high when the weather is good

Perch in large flocks before returning to Africa

Nests are against a beam or shelf in buildings or a ledge on cliffs
Old nests get refurbished, some even reused for 50 years
Nest in loose colonies or singly
Female incubates the eggs
Both male and female feed the young



white with reddish speckles, smooth, glossy, 20 mm by 14 mm

Juveniles: duller in colour, shorter tail, lack the red throat


Catch insects on the wing, in open areas above shallow waters or ground

Drink by flying low over water, scooping up water from the surface


The long forked tail gives exceptional flight manoeuvrability, much better than the swifts’ or martins’

Barn Swallow - © I, Malene [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/)]

Barn Swallow
(© I, Malene [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/)])

Barn Swallow Nest © Mario Modesto Mata [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
Barn Swallow Nest
(© Mario Modesto Mata [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)])
  • Breeding starts: April-May
  • Clutches: 2-3
  • Eggs: 3-8
  • Incubation: 14-16 days
  • Fledge: 17-24 days
Barn Swallow In Flight © www.birdsna.org
Barn Swallow In Flight
(© Birdsna.org)

House Martins       

House Martin © Mike Langman (rspb-images.com)
House Martin
(© Mike Langman (rspb-images.com))


Distinctive, bright white throat and rump
Glossy blue-black upper parts
Brown-black wings and tail
Black beak
White-feathered legs and feet


More solid in shape
Lacks streamers
Shorter than a swallow’s tail






Length: 12 cm
Wingspan: 26-29 cm
Weight: 15-23 g


Song: a sharp “jik, jik” with ongoing, babbly twittering:

Call: a weak chirrup:
© Jean Roché, Sittelle.com (Garden-birds.co.uk)


Eggs: white, smooth, matt, 19 mm by 14 mm

Juveniles: brown crowns, the white areas are buff-grey


Feed during flight on insects such as flies, beetles, and aphids


Winter habitat: tropical Africa
Visit Britain between mid-April and October
Natural habitats: farmland, urban and suburban, wetland

Nest in colonies

Build mud cups under the eaves of houses - during dry periods, you can help them by leaving an area of wet mud for them to use
Use the same nest for several years
Male and female both feed the young and take turns incubating the eggs


House martins are smaller than swallows

They can be confused with sand martins, who are smaller, brown, appear paler, have a breast band, lack the white rump, and they nest in sand banks and quarries

House Martin © Mike Langman (rspb-images.com)
House Martin
Julien Daubignard, Oiseaux.net)
House Martin Nest - © M Palmer photorasa.com
House Martin Nest
M Palmer photorasa.com)
  • Breeding starts: April-May
  • Clutches: 2-3
  • Eggs: 2-6
  • Incubation: 12-19 days
  • Fledge: 19-25 days
House Martin Chicks © www.limburger.nl
House Martin Chicks
(© Limburger.nl)
 House Martin In Flight © http://www.record-lrc.co.uk/Images/Uploads/SpeciesSpotlight_holder/May%20-%20house%20martin.jpg
Last But Not Least: Not a House Martin, But an Adorkable Looking Sand Martin - © Axel Strauß [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/)]
Last But Not Least: Not a House Martin, But an Adorkable Looking Sand Martin
(© Axel Strauß [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/)])


  • Allana Gray

    This is such a great article, really informative. For years, since a child, I thought the birds which nested in our shed as a child were swallows but now I think they were House Martin’s. It’s difficult to identify them, they fly so fast! Thank you

  • Terry Baker

    Thank you for helping us identify our swifts and swallows. We live in rural Peterborough and have more swallows than in previous years. They fly around in large groups – lovely to see.

  • Christopher Armstrong-Stevenson

    Thank you for this clarification – I knew they were NOT swallows because of tail length, but the differences between House martins and Swifts eluded me. I now know I have House Martins – and they’re welcome. I live near the beach (Pacific Ocean) on the coastline of Oregon (NW part of the USA). I also have a very busy crowd of Hummingbirds – mostly Anna’s. They are a joy to watch – I have three large Fuchsia baskets with varied species, (including the Winston Churchill one) that the Hummers use as a feeding station.

  • Joy Christopher

    Brilliant thank you. I’ve been excitedly watching my ‘swallows’ as I thought, now know them to be swifts since the beginning of April. I’m in the wilds of Norfolk and you wouldn’t think there was a shortage of them if you were here! We found one on the ground in a corner up against the house, it seemed to be trying to climb up the wall! We left it for a while, thinking it would take off in time and kept our cat in. Four hours later it was still there, a friend told us if it can’t take off its a swift and you have to throw it into the air! With great trepidation my partner picked it up gently in both hands and threw it quite strongly facing forward. it wobbled a bit then soared off over the neighbouring rooftops

  • Anet

    I have just helped out one of our constant swift visitors to our flat in Barcelona. I love watching them in spring circling and screaming in the immense interior patio space. The catch the updrafts of warm air as I open the French windows.

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