[order] Passeriformes | [family] Hirundinidae | [latin] Delichon urbica | [UK] Northern House-Martin | [FR] Hirondelle de fenêtre | [DE] Mehlschwalbe | [ES] Avión Común | [IT] Balestruccio | [NL] Huiszwaluw

Huiszwaluw determination

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Medium size Hirundinidae, smaller than Barn Swallow, but head and body appear hardly less bulky due to proportionately shorter wings and tail. Uperparts blue-black with broad white rump. Underbody white. Flight less rapid and often at greater heigh than Barn Swallow. Sexes closely similar, some seasonal variation.

Breeds sparsely from shbarctic and boreal, and more abundantly through temperate to steppe and Mediterranean zones of west Palearctic, in oceanic as well as continental climates but usually avoiding extremes of temperature, and vulnerable to their effects on insect prey. In suitable weather, tends to forage in airspace above lowest levels favoured by Barn Swallow, but spends rather less of day in flight and, at least in north of range, seems to range less far from nest. Although transition from primitive rock-nesting to general use of buildings, bridges, and other artefacts is virtually complete over much of Europe, in some regions nesting on natural rock-faces with suitable surfaces and pitches remains locally common.

Delichon urbica is a widespread summer visitor to most of Europe, which accounts for less than half of its global breeding range. Its European breeding population is very large (>9,900,000 pairs), and was stable between 1970-1990. Although the species remained stable in several countries during 1990-2000, it declined across much of its European range-including the sizeable populations in Turkey, France and Germany- and probably underwent a moderate decline (>10%) overall.

Almost wholly flying insects, in breeding season, especially flies and aphids. Prey taken almost entirely by aerial pursuit, though many reports of birds feeding while perched on ground or trees-also from walls, rock faces, and reeds.

This species has a large range, with an estimated global Extent of Occurrence of 10,000,000 km². It has a large global population, including an estimated 20,000,000-48,000,000 individuals in Europe (BirdLife International in prep.). Global population trends have not been quantified; there is evidence of population fluctuations (Turner and Rose 1989, Snow and Perrins 1998), but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]

Breeding starts May-April in North-West and Central Europe, May-June in northern and North-East Europe. Nest site, most frequent on outer walls of buildings, under caves or other overhang, also under bridges, culverts, etc, natural sites are on cliffs and outcrops, coastal and inland, also under overhangs.
Colonial bird with a nest half-cup of mud pellets, down, feathers, and other light material. Cup formed against vertical wall and overhanging 'roof' with small oval entrance at top. Building by both sexes though male more active at start. Clutch size 6-8 eggs, incubation period 14-16 days done by both sexes.

The winter range covers Africa south of the Sahara, India and southeast Asia. The nominate race winters predominantly throughout Africa south of the Sahara, but there are also winter records from India, mainly on the western side. The eastern race winters in southern China, Burma, Thailand and Indochina, and has been recorded in Sakhalin in Japan. A few House Martins winter in North Africa, and there are occasional winter records in Europe, including Britain. The autumn migration takes place on a broad front south through Europe and Asia to the winter quarters; the peak of migration is from the end of August to the beginning of October in western and central Europe, later in southern parts of the range. The main return to the breeding grounds is in April and May. In its winter quarters this species is usually seen in small flocks; it is a less conspicuous winter visitor than the Barn Swallow, partly because it is mor nomadic and flies at greater heights. Vagrant House Martins are known over a wide area, including the Azores, Bermuda, Ascension Island, Cape Verde Islands, South Georgia, Nepal, Maldives, Iceland, Greenland, and western Alaska.