Barn Swallow

识别特征

The adult male barn swallow of the nominate subspecies H. r. rustica is .mw-parser-output .frac{white-space:nowrap}.mw-parser-output .frac .num,.mw-parser-output .frac .den{font-size:80%;line-height:0;vertical-align:super}.mw-parser-output .frac .den{vertical-align:sub}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}17–19 cm (6+1⁄2–7+1⁄2 in) long including 2–7 cm (1–3 in) of elongated outer tail feathers. It has a wingspan of 32–34.5 cm (12+1⁄2–13+1⁄2 in) and weighs 16–22 g (9⁄16–3⁄4 oz). It has steel blue upperparts and a rufous forehead, chin and throat, which are separated from the off-white underparts by a broad dark blue breast band. The outer tail feathers are elongated, giving the distinctive deeply forked "swallow tail". There is a line of white spots across the outer end of the upper tail. The female is similar in appearance to the male, but the tail streamers are shorter, the blue of the upperparts and breast band is less glossy, and the underparts paler. The juvenile is browner and has a paler rufous face and whiter underparts. It also lacks the long tail streamers of the adult.<p>Although both sexes sing, female song was only recently described. (See below for details about song.) Calls include witt or witt-witt and a loud splee-plink when excited or trying to chase intruders away from the nest. The alarm calls include a sharp siflitt for predators like cats and a flitt-flitt for birds of prey like the hobby. This species is fairly quiet on the wintering grounds.<p>The distinctive combination of a red face and blue breast band renders the adult barn swallow easy to distinguish from the African Hirundo species and from the welcome swallow (Hirundo neoxena) with which its range overlaps in Australasia. In Africa the short tail streamers of the juvenile barn swallow invite confusion with juvenile red-chested swallow (Hirundo lucida), but the latter has a narrower breast band and more white in the tail.

分类信息

The barn swallow was described by Carl Linnaeus in his 1758 10th edition of Systema Naturae as Hirundo rustica, characterised as "H. rectricibus, exceptis duabus intermediis, macula alba notatîs". Hirundo is the Latin word for "swallow"; rusticus means "of the country". This species is the only one of that genus to have a range extending into the Americas, with the majority of Hirundo species being native to Africa. This genus of blue-backed swallows is sometimes called the "barn swallows".<p>The Oxford English Dictionary dates the English common name "barn swallow" to 1851, though an earlier instance of the collocation in an English-language context is in Gilbert White's popular book The Natural History of Selborne, originally published in 1789:<p>The swallow, though called the chimney-swallow, by no means builds altogether in chimnies [sic], but often within barns and out-houses against the rafters ... In Sweden she builds in barns, and is called ladusvala, the barn-swallow.<p>This suggests that the English name may be a calque on the Swedish term.<p>There are few taxonomic problems within the genus, but the red-chested swallow—a resident of West Africa, the Congo Basin, and Ethiopia—was formerly treated as a subspecies of barn swallow. The red-chested swallow is slightly smaller than its migratory relative, has a narrower blue breast-band, and (in the adult) has shorter tail streamers. In flight, it looks paler underneath than barn swallow.<p>Six subspecies of barn swallow are generally recognised. In eastern Asia, a number of additional or alternative forms have been proposed, including saturata by Robert Ridgway in 1883, kamtschatica by Benedykt Dybowski in 1883, ambigua by Erwin Stresemann and mandschurica by Wilhelm Meise in 1934. Given the uncertainties over the validity of these forms, this article follows the treatment of Turner and Rose.<p>The short wings, red belly and incomplete breast band of H. r. tytleri are also found in H. r. erythrogaster, and DNA analyses show that barn swallows from North America colonised the Baikal region of Siberia, a dispersal direction opposite to that for most changes in distribution between North America and Eurasia.

学名

Hirundo rustica

命名信息

Linnaeus, 1758

目

Passeriformes

科

Hirundinidae

属

Hirundo

分布与栖息地

迁徙

Complete migrants

行为

Migration pattern: Complete migrants.

保护状况

Population trend: declining.

种群趋势

declining