Hirundo rustic

The Barn Swallow has a nearly cosmopolitan breeding range. It occurs as a common breeding bird across much of North America, from southeastern Alaska across southern Canada and south through the United States and much of Mexico (A.O.U. 1983). Like the other two members of its genus, the Barn Swallow rapidly expanded its breeding range in Texas, beginning in the 1960s; this expansion is strongly related to road-building practices that began during within that time-frame.

DISTRIBUTION: In Texas, the TBBA data demonstrate the widespread breeding across the state. Mapping of the known breeding locations might easily duplicate a road map, especially of roads constructed in the past 30 years.

SEASONAL OCCURRENCE: Males arrive on the breeding ground earlier than the females and establish small territories which contain perches and potential nest sites. Courtship takes place in aerial displays in which each male attempts to lead a female to one or more nest sites. (Møller 1994).

The Barn Swallow is easily confirmed, as the adults regularly circle around the nest site either during the time of nest construction or while eggs or young are in the nest. Of the 1,817 records reported to the TBBA project, 64.4% were confirmed records. Of these reports, 984 were of active nests containing eggs or young, adults on the nest or in the nest-building stage.

This species has an extended breeding season and two or more clutches are common. Oberholser (1974) indicates a breeding season lasting from late March through mid-August; he records extreme egg dates as 8 April and 1 August. In a two-year study on the breeding biology of Barn Swallows in Brazos County, Barr (1979) reports the earliest egg-laying as 27 March and the latest as 20 July; by 8 August no nest contained eggs. The earliest nest with eggs among the TBBA data was recorded on 11 April 1987 for latilong 30096, quad E4 and 11 April 1990 for latilong 29100, quad B1. However, an early date of 3 April 1988 for nest with young in latilong 29095, quad E6, indicates that egg-laying occurred no later than 20 March, perhaps earlier, given an incubation period of 14-15 days (Barr 1979). The latest reported date for a nest with eggs was 2 August 1987 in latilong 34102, quad D3. The latest date for nest with young was recorded on 2 August 1990 in latilong 30099, quad C1; obviously, with a reported nestling period of 18 days (Barr 1979), if the eggs reported for this same date were viable, the nest would have been active into mid-August.

BREEDING HABITAT: This swallow relies heavily upon man-made structures for nesting sites. The majority of the TBBA reports represent one or more nests in highway culverts or under bridges. Buildings, either inhabited or abandoned, also receive much use by Barn Swallows, although these structures appear to be much less important for current Texas populations. Oberholser (1974) states that “…in wilder places the bird still nests where it did–in rocky, shallow caves or on shelves of projecting rocks.” However, no such nesting places were reported in the TBBA project. Unlike their congeners, Barn Swallows do not build in close proximity of each other; where more than one nest exists in a culvert or on a building, they will be spaced at regular intervals.

The mud nests, built on sites with an open approach, are lined with horse hair, white chicken feathers or even nylon fishing line (Barr 1979). Although the same nest may be used for a second or later brood, Barr (1979) found that over 80% of the double-brooding pairs used the same nest. These nests, however, do not survive to the next breeding season.

STATUS: The status of the Barn Swallow in Texas is excellent, with improvement especially noticeable in the past 25 years, until the species occurs in almost every part of the state. Oberholser (1974) mapped nesting for this swallow for many parts of the state, including a number of “summer” records, but did not indicate any breeding in the Piney Woods region of east Texas, in the South Plains, or the north-eastern quarter of the Edwards’ Plateau. Data from TBBA efforts indicate the presence of the Barn Swallow in every latilong and confirmed nesting in all but two latilongs.

The TBBAP data indicate that the Barn Swallow continues to increase as a breeding bird in Texas. The continuing highway construction likely will aid this species in expanding to virtually every part of the state.

Text by Keith A. Arnold (ca. 1995)

Literature cited

American Ornithologists’ Union. 1983. Check-list of North American Birds, 6th ed. Am. Ornithol. Union, Washington, DC.

Barr, A. L. 1979. Nesting success, growth rates, and recruitment of Barn Swallows (Hirundo rustica) in Brazos County, Texas. M.S. thesis, Texas A&M University, College Station.

Møller, A. P. 1994. Sexual selection and the Barn Swallow. Oxford University Press,, New York.

Oberholser, H. C. 1974. The Bird Life of Texas. vol. 2. University of Texas Press, Austin.