Common House Martin

• Its nest is a closed half-sphere of mud pellets with a small entrance at the top, put up by the pair in about ten days over hundreds of trips.
• A study in Scotland found that 15% of the chicks were not the offspring of the male raising them, and that 32% of broods contained at least one chick by another father.
• The chicks of the first brood stay with the family and help feed their siblings from later ones.

Skeleton type

Vertebrate - internal bony skeleton (bird)

Habitat and environment

Towns and cities across temperate Eurasia and North Africa, where it breeds under eaves and bridges. It keeps colonies on natural rock faces up to an altitude of 2,200 m. It winters in sub-Saharan Africa and tropical Asia

Gestation / incubation

12-19 days of incubation (usually 14-15), by both parents. The chicks stay in the nest for 24 to 28 days

Litter / clutch size

3-6 eggs, with two clutches a year and sometimes three. The size decreases: an average of 5 eggs in the first, 4 in the second and 3 in the third

Sources consulted: SEO/BirdLife (ficha del avión común occidental) · IUCN Red List · Asturnatura · Turner y Rose 1989, Swallows & Martins · Carrascal y Palomino 2008, Las aves comunes reproductoras en España

Best time: From March to September in Spain; the first arrive in February in the south of the peninsula