Six subspecies of the barn swallow are generally recognized.
Six subspecies of the barn swallow are generally recognized, all of which breed across the Northern Hemisphere. Four are strongly migratory, and their wintering grounds cover much of the Southern Hemisphere as far south as central Argentina, the Cape Province of South Africa, and northern Australia.
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. There are uncertainties over the validity of these forms.
H. r. rustica, the nominate European subspecies, breeds in Europe and Asia, as far north as the Arctic Circle, south to North Africa, the Middle East and Sikkim, and east to the Yenisei River. It migrates on a broad front to winter in Africa, Arabia, and the Indian subcontinent. The barn swallows wintering in southern Africa are from across Eurasia to at least 91°E, and have been recorded as covering up to 11,660 kilometers (7,250 miles) on their annual migration. The nominate European subspecies was the first to have its genome sequenced and published.
H. r. transitiva was described by Ernst Hartert in 1910. It breeds in the Middle East from southern Turkey to Israel and is partially resident, though some birds winter in East Africa. It has orange red underparts and a broken breast band.
H. r. savignii, the resident Egyptian subspecies, was described by James Stephens in 1817 and named for French zoologist Marie Jules César Savigny. It resembles transitiva, which also has orange-red underparts, but savignii has a complete broad breast band and deeper red hue to the underparts.
H. r. gutturalis, described by Giovanni Antonio Scopoli in 1786, has whitish underparts and a broken breast band. Breast chestnut and lower underparts more pink-buff. The populations that breed in the central and eastern Himalayas have been included in this subspecies, although the primary breeding range is Japan and Korea. The east Asian breeders winter across tropical Asia from India and Sri Lanka east to Indonesia and New Guinea. Increasing numbers are wintering in Australia. It hybridises with H. r. tytleri in the Amur River area. It is thought that the two eastern Asia forms were once geographically separate, but the nest sites provided by expanding human habitation allowed the ranges to overlap.
H. r. gutturalis is a vagrant to Alaska and Washington, but is easily distinguished from the North American breeding subspecies, H. r. erythrogaster, by the latter’s reddish underparts.
H. r. tytleri, first described by Thomas Jerdon in 1864, and named for British soldier, naturalist and photographer Robert Christopher Tytler, has deep orange-red underparts and an incomplete breast band. The tail is also longer. It breeds in central Siberia south to northern Mongolia and winters from eastern Bengal east to Thailand and Malaysia.
H. r. erythrogaster, the North American subspecies described by Pieter Boddaert in 1783, differs from the European subspecies in having redder underparts and a narrower, often incomplete, blue breast band. It breeds throughout North America, from Alaska to southern Mexico, and migrates to the Lesser Antilles, Costa Rica, Panama and South America to winter. A few may winter in the southernmost parts of the breeding range. This subspecies funnels through Central America on a narrow front and is therefore abundant on passage in the lowlands of both coasts.
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.
• Image | © Bernard DUPONT, Some Rights Reserved, (CC BY-SA 2.0)
• Sources | (Dekker, 2003; Dickinson & Dekker, 2001; Dickinson, Eck, & Milensky, 2002; Formenti, et al., 2019; Hilty, 2003; Moller, June 1994, July 1994; Rasmussen & Anderton, 2005; Roth, 2002; Sibley, 2007; Stiles & Skutch, 2003; Svensson, Mullarney, & Zetterstrom, 2010; Terres, 1991; Turner & Rose, 1989; Vaurie, 1951; The Wikimedia Foundation, 2019; Zink, Pavlova, Rohwer, & Drovetski, 2006)
