About Stelgidopteryx ruficollis (Vieillot, 1817)
The southern rough-winged swallow, scientific name Stelgidopteryx ruficollis (Vieillot, 1817), is about 13 cm (5.1 in) long and weighs 14 to 18 g (0.49 to 0.63 oz). Males and females have almost identical plumage. For the nominate subspecies S. r. ruficollis, adult males have a mostly dark gray-brown head with a cinnamon-colored throat. Their upperparts are mostly dark gray-brown, with a slightly paler rump. They have a square-shaped tail; both the tail and wings are blackish brown. The outer primaries of their wings have stiff, recurved barbs on their outer webs, which is where the species gets its common English name. Females do not have 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.
Four subspecies are recognized, each with distinct traits beyond the nominate. 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 have separate distribution ranges across the Americas. S. r. uropygialis ranges from eastern Honduras south through eastern Nicaragua, northern and eastern Costa Rica, most of Panama, western Colombia, and western Ecuador into extreme northwestern Peru. S. r. decolor is found in western Costa Rica and western Panama. S. r. aequalis is found in northern Colombia, western Venezuela, and Trinidad. The nominate subspecies S. r. ruficollis ranges 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 it extends east across southern and eastern Venezuela, the Guianas, and all of Brazil, Paraguay, and Uruguay.
The species has been recorded as a vagrant on the Caribbean islands of Aruba, Bonaire, Curaçao, and Tobago (which lie off the north coast of South America), and also far to the southeast on the Falkland Islands. The southern rough-winged swallow lives in a wide range of open landscapes, especially areas with water features. It also occurs in clearings within forest. Most populations are found up to about 1,000 m (3,300 ft) above sea level, but there are records of individuals as high as 3,600 m (11,800 ft). Elevation limits vary by region: 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. In Brazil, it mostly occurs below 1,000 m (3,300 ft), and "occasionally much higher".
