The western house martin (Delichon urbicum), sometimes called the common house martin, northern house martin or, particularly in Europe, just house martin, is a migratory passerine bird of the swallow family which breeds in Europe, north Africa and across the Palearctic; and winters in sub-Saharan Africa and tropical Asia. It feeds on insects which are caught in flight, and it migrates to climates where flying insects are plentiful. It has a blue head and upperparts, white rump and pure white underparts, and is found in both open country and near human habitation. It is similar in appearance to the two other martin species of the genus Delichon, which are both endemic to eastern and southern Asia. It has two accepted subspecies.
Both the scientific and colloquial name of the bird are related to its use of human-made structures. It builds a closed cup nest from mud pellets under eaves or similar locations on buildings usually in colonies.
It is hunted by the Eurasian hobby (Falco subbuteo), and like other birds is affected by internal parasites and external fleas and mites, although its large range and population mean that it is not threatened globally.
The western house martin breeds across temperate Eurosiberia east to central Mongolia and the Yenisei River, and in Morocco, Tunisia and northern Algeria, and migrates on a broad front to winter in sub-Saharan Africa.
The preferred habitat of the western house martin is open country with low vegetation, such as pasture, meadows and farmland, and preferably near water, although it is also found in mountains up to at least 2,200 m (7,200 ft) elevation. It is much more urban than the barn swallow, and will nest even in city centres if the air is clean enough. It is more likely to be found near trees than other Eurasian swallows, since they provide insect food and also roosting sites. This species does not normally use the reed-bed roosts favoured by migrating barn swallows.
It uses similar open habitats on the wintering grounds, but the western house martin is less conspicuous than wintering barn swallows, tending to fly higher and be more nomadic. In the tropical parts of its wintering range, like East Africa, it appears to be mainly found in the higher areas.
