Delichon urbicum
A cheerful summer visitor that plasters mud nests under the eaves.
Size: 12-13 cm | Habitat: Farmland & Countryside Birds | Season: Summer visitor
Glossy blue-black above with a bright white rump and pure white underside, the house martin is a familiar sight skimming over rooftops and gardens each summer. It builds an enclosed mud nest of roughly a thousand tiny pellets under eaves, often nesting in noisy colonies on the same house year after year.
Blue-black upperparts · bright white rump · white underparts, no chest band · short forked tail, no streamers
House martins feed on flying insects caught on the wing, often high overhead in mixed flocks with swallows and swifts. They build enclosed cup nests under house eaves and readily reuse or repair last year's nest.
The UK population has fallen by more than half since 1969, likely as smooth modern eaves and a decline in flying insects leave fewer places to nest and less to eat.
The House Martin (Delichon urbicum) is a glossy blue-black relative of the swallow, told apart at a glance by its bright white rump and pure white underside, and by its short, only lightly forked tail.
House martins depend almost entirely on buildings to breed, plastering an enclosed mud nest of roughly a thousand tiny pellets under eaves, often in noisy colonies on the same house for generations. The species was newly Red-listed in BoCC5 after a 57% UK population decline between 1969 and 2018, with an even steeper 75% drop recorded in England alone — likely a combination of smoother modern eaves offering fewer nest sites and a broader decline in the flying insects it depends on.
Because house martins nest so visibly on people's own homes, their decline is one of the more noticeable to the public, and simple measures such as leaving existing nests undisturbed and installing artificial nest cups are genuinely meaningful ways households can help.
🔴 Conservation status: Red (UK Birds of Conservation Concern 5)
Red-listed after a 57% UK decline (1969-2018), with an even steeper fall in England, linked to fewer natural nest sites on modern buildings and a decline in flying insect prey.