Southern Rough-winged Swallow

The southern rough-winged swallow is about 13 cm (5.1 in) long and weighs 14 to 18 g (0.49 to 0.63 oz). The sexes have almost the same plumage. Adult males of the nominate subspecies S. r. ruficollis have a mostly dark gray-brown head with a cinnamon throat. Their upperparts are mostly dark gray-brown with a slightly paler rump. Their tail is square; it and their wings are blackish brown. Their wings' outer primaries have stiff recurved barbs on their outer webs that give the bird its English name. Females lack these barbs. Both sexes have a dark gray-brown breast, a yellowish gray-brown belly, and white undertail coverts. Juveniles have a duller throat than adults and pale edges on the feathers of their back. Subspecies S. r. decolor is paler overall than the other subspecies and has thin dark streaks on its underparts. S. r. uropygialis has a whitish rump. S. r. aequalis has light brown upperparts with a paler rump and a tawny-buff throat.

The subspecies of the southern rough-winged swallow are found thus:

S. r. uropygialis: from eastern Honduras south through eastern Nicaragua, northern and eastern Costa Rica, much of Panama, western Colombia, and western Ecuador into extreme northwestern Peru S. r. decolor: western Costa Rica and western Panama S. r. aequalis: northern Colombia, western Venezuela, and Trinidad S. r. ruficollis: from southeastern Colombia south through eastern Ecuador, eastern Peru, and eastern Bolivia into northern and northeastern Argentina as far as Buenos Aires Province; from there east across southern and eastern Venezuela, the Guianas, and all of Brazil, Paraguay, and Uruguay The species has been documented as a vagrant on the Caribbean islands of Aruba, Bonaire, Curaçao, and Tobago that are arrayed along the north coast of South America, and also far to the southeast on the Falkland Islands. The southern rough-winged swallow inhabits a variety of open landscapes, especially those that have water features. It also occurs in clearings within forest. Overall it mostly is found up to about 1,000 m (3,300 ft) above sea level but there are records as high as 3,600 m (11,800 ft). It reaches 1,200 m (3,900 ft) in Honduras, 1,800 m (5,900 ft) in Costa Rica, 2,200 m (7,200 ft) in Colombia, 1,500 m (4,900 ft) in Ecuador and Peru, and 1,600 m (5,200 ft) in Venezuela. …

The southern rough-winged swallow feeds on insects captured in mid-air; its diet is not known in detail but includes flies (Diptera), beetles (Coleoptera), true bugs (Heteroptera), and Hymenoptera such as flying ants. It typically forages in small flocks with slow flight low to the ground or somewhat higher, and over both land and water.