under your eaves is a lovely address. we'll bring friends.
House martin says
Bird 20 of 30 · video, 33:16
House martin
Delichon urbicum
A spring arrival with a white rump and a short forked tail, nesting in a colony on the outside of your house.
- Small, 17.8 g
- Summer visitor
- Building or eaves
- In the air
About the house martin
Marks and dots
Tap a numbered dot, or a name in the list.
A conspicuous white rump, easiest to see in flight.
A much shorter forked tail than a swallow's.
From egg to adult
-
Egg
Eggs4–5 eggs video, BTO agrees
Hatch after15 days video, BTO agrees
-
Chick in the nest
In the nest for21 days video, BTO agrees
-
Young bird
Chicks of an earlier brood often help feed later nestlings.
Adult
White rump, short forked tail
Broods a year2 broods≠BTOthe video says up to 3 broods
BTO prints no average incubation and nest time for this bird, so there is no nest clock.
At the table
- insects caught in flight (BTO)
The video does not say what house martins eat. BTO says flocks gather in early autumn to catch insects ahead of the journey south.
Through the year
House martin: around Mar to Oct; back each spring, Mar to May; flocks overhead in early autumn, Sep to Oct. Spring is read as March to May and early autumn as September to October.
What to know about the house martin
Eight short notes in our own words. Each chip says what the note stands on, and links to its row in the table below.
What to look for
Told from its swallow cousin by a conspicuous white rump, easy to see in flight, and a much shorter forked tail.
Male and female
The video does not say whether male and female house martins look different.
not in the video
Nest
Originally a cliff nester, it now nests under the eaves of houses, hence the name. Unlike a swallow, which nests inside, a house martin always fixes its nest to the outside.
Feeding
The video does not say what house martins eat. BTO says flocks gather in early autumn to catch insects ahead of the journey south.
not in the video
Staying or leaving
A welcome sight each spring, returning from migration. The video says from as far afield as Africa, India and South East Asia. BTO says they go to Africa, and that where the British ones spend the winter is still not known, so this guide leaves out India and South East Asia.
In the garden
If one pair nests with you, expect more. They are sociable colony birds that breed prolifically. Numbers are falling, but breeding keeps them fairly widespread, so BTO has them on the Red List.
Sources and checks
Where every fact about the house martin came from
16 claims about the house martin: 6 checked, 6 from the video only,2 differ, 2 from a source only. How the grades work
| Claim, in our words | Video time | Grade | What the source says |
|---|---|---|---|
| The house martin has a conspicuous white rump, particularly in flight. | 33:27 | checked | BTO, read 2026-10-05BTO says the birds have a distinctive white rump. |
| Its tail is much shorter and forked, compared with a swallow's. | 33:34 | video only | |
| Like its swallow relative it is a welcome sight each spring, returning after migration from as far afield as Africa, India and South East Asia.video: Africa, India and South East Asia | 33:16 | ≠differs | BTO, read 2026-10-05: migrate to Africa; the exact non-breeding range of British birds is still not knownBTO's introduction to the species. |
| Early in the video: summer brings house martins and swallows back to British gardens from the Southern Hemisphere, and nesting pairs often return year after year. | 03:24 | video only | |
| BTO says house martins migrate to the UK and Ireland in early spring, and flocks gather overhead in early autumn before the return migration. | source only | source only | BTO, read 2026-10-05BTO's introduction to the species. |
| It now nests under the eaves of houses, hence its descriptive name. | 33:42 | checked | BTO, read 2026-10-05BTO says house martins nest in small colonies under the eaves of buildings. |
| Originally the species was a cliff nester. | 33:38 | video only | |
| The house martin always attaches its nest to the exterior of the house, where a swallow builds inside. | 33:50 | video only | |
| If you have one pair of house martins you will invariably find you have more; they are gregarious, living in colonies and breeding prolifically. | 34:00 | video only | |
| A colony looks intensely active, with swooping and chattering birds; offspring of an earlier brood often help feed later nestlings. | 34:26 | video only | |
| House martin numbers are in decline but thanks to prolific breeding they remain fairly widespread. | 34:37 | checked | BTO, read 2026-10-05BTO says declines led to the UK Red List in 2020, and that the birds can be seen anywhere in Britain and Ireland in summer. |
| Each pair can produce three broods a year.video: up to 3 broods | 34:08 | ≠differs | BTO, read 2026-10-05: 2 broods (BTO typical)BTO lists 2 as typical and prints no higher figure, not 3 |
| Usually four to five eggs.video: 4–5 eggs | 34:11 | checked | BTO, read 2026-10-05: 4–5 eggs (BTO typical)inside BTO's typical range of 4–5 |
| They incubate within 15 days.video: 15 days | 34:16 | checked | BTO, read 2026-10-05: 13–19 days (BTO typical)inside BTO's typical range of 13–19 |
| The young fly by the time they are three weeks old.video: 21 days | 34:19 | checked | BTO, read 2026-10-05: 19–25 days (BTO typical)inside BTO's typical range of 19–25 |
| Adult weight, from ringing records: 17.8 g, adult average. | source only | source only | BTO, read 2026-10-05: 17.8 g, adult average |
Written in our own words after “British Birds in your Garden” by The Great British Channel, where the house martin starts at 33:16.Numbers are checked against the BTO's page for the house martin, read on 5 October 2026. We are not connected to the channel or to the BTO.
More birbs: 30 so far, and more to come
The coins down the right of the screen are all 30. Tap one to go to that bird.