Barn Swallow

Hirundo rustica

Introduction

The Barn Swallow is the most widely distributed and abundant swallow in the world. It breeds throughout most of North America, Europe, and Asia and winters in Central and South America, southern Spain, Morocco, Egypt, sub-Saharan Africa, the Middle East, India, Indochina, Malaysia, and Australia.

Identification

Adult Male (spring/summer)

Nape and upper back dark gray / blackish, darker head with white eye crescents and dark tail showing white corners in flight. Bill yellow often with a black tip. Breast, belly red. Vent and undertail coverts white.

Adult Female (spring/summer)

Belly, flanks and undertail coverts buffy white and tail is shorter.

Juvenile

Buffy on forehead, chin and throat. Dusky blue-black on remainder of head, back and wings. Not as slender as adults with shorter tail.

General Information

General:

Very long, slender swallow. Length: 17-18cm. Wing: 38-38.5cm. Weight: 19grams.

Behaviour:

The Barn Swallow is the most widespread species of swallow in the world and a familiar inhabitant of barns and other outbuildings. A bird of open country it was originally a cave breeder but now normally uses man made structures to breed and consequently has spread with human expansion. It flies at various heights from just above ground to ≥25 m. Flight consists of bursts of straight flight longer than those of other swallows; birds frequently alter course slightly to left or right. Flight may be circular when feeding over an insect concentration, such as around cattle and birds are capable of sharper turns and dives than other swallows. Increased maneuverability is a consequence of the highly forked tail; outer tail-streamers deflect leading edge of tail, resulting in higher aerodynamic lift and allowing tighter turns. Goes to ground only to collect mud, grass, or feathers for nest, to pick up bits of gravel or (rarely) moribund insects, to sunbathe, or to seek refuge from strong winds. Slides along a wire, tree branch, or other perching substrate using a sideways walk.

Habitat:

The Barn Swallow has the distinction of being perhaps the only northern temperate breeder that commonly winters in South America and occasionally also breeds there during the boreal winter; Barn Swallows have been reported nesting in small numbers in northern Argentina. Originally nesting primarily in caves, the Barn Swallow has almost completely converted to breeding under the eaves of buildings or inside artificial structures such as bridges and culverts. In North America, this shift in nest sites began before European settlement and was virtually complete by the mid-twentieth century; nowadays-natural nesting’s are rarely seen and usually reported in print if they occur. As with other swallows that have shifted to nesting on human-made structures, such as the Purple Martin, Barn Swallows now sometimes nest in larger colonies than probably occurred in natural settings.

Information:

As a consequence of both its wide distribution and its nesting on accessible artificial structures near people, the Barn Swallow has been studied extensively throughout the world and especially in Europe. More papers have been published on this species than on any other swallow, and it is one of the most thoroughly studied birds in the world. In addition, these swallows—not the more famous egrets—have the distinction of having indirectly led to the founding of the conservation movement in the United States: the destruction of Barn Swallows for the millinery trade apparently prompted George Bird Grinnell’s 1886 editorial in Forest and Stream that led to the founding of the first Audubon Society.

Conservation Status:

Provincially blue listed, COSEWIC N.A., Global G5 (1996). On balance, human activity has had strongly positive effects on this species: construction of artificial structures has provided abundant nesting sites, leading to population size that is probably several orders of magnitude greater than before European settlement of North America. Barn Swallows are popular with people, and farmers often protect (rarely persecute) the birds on their property. The species seems to have adapted well to nesting in human-altered habitats in North America and worldwide. Listed as Least Concern (IUCN 3.1)

Maps & Statistics

Capture Rates

The Barn Swallow has the longest migration of North American swallows and numbers peak in August as juveniles disperse. Capture rates at Colony Farm correspondingly peak in August and are lacking from Oct through April.

Ageing and Sexing (Band Size: 0, 1)

Molt Summary:

PF: HY/SY complete (Oct-Apr), PB: AHY/ASY complete (Aug-Feb); PA absent (?) Molt occurs primarily on the winter grounds.

Juvenile-HY

June - December

Upperparts buffy and brownish with buffy orange throat (photos below) and very pale underparts. Juvenal birds in summer show prominent, soft, yellowish gapes.

This HY in August is showing buffy fringes to the wing coverts and fresh remiges (primaries and secondaries) with little or no wear.

Hatch year (HY) tail lengths (both male and female) are normally less than 67mm with shallow tail fork (r6 – r1) less than 20 mm (photos below of HY birds in August).

AHY/ASY

April - March

Molt limits are not helpful in Barn Swallows as both the preformative and adult prebasic molt is complete.

Adults can however easily be separated from juvenal birds and males from females by the length of the tail and depth of the tail notch.

Adult tail length is generally more than 67/68mm and tail fork deep with r6 – r1 more than 26mm.

Upperparts are uniformly metallic blue and wing coverts and tertials edged with thin whitish edging.

Male: Upperparts glossy blue with dark rusty breast (photo below – AHY male in June) and long tail (80-107) with deep tail fork (r6 – r1) measuring 35mm – >50mm.

Female: Upperparts dullish blue with pale buffy breast. Tail long but not as long as male (67-83) and shallower tail fork (r6 – r1) measuring 25-37mm.

This AHY female in August lacks the buffy fringes to the wing coverts of HY birds and is showing more wear to the visible primaries.

AHY female tail lengths are generally shorter than AHY males with a shallower tail fork (r6 – r1) less than 38 mm (photos below of AHY female in August).