White-winged Swallow

This elegant and slender member of the Hirundinidae family is easily recognized by its iridescent blue-green upperparts, which contrast sharply with its clean white underparts. The most prominent diagnostic feature of this species is the conspicuous white wing patch, formed by the broad white margins of the secondary and tertial feathers, highly visible both when perched and in flight. It has a tiny, indistinct white supraloral spot that does not form a complete eyebrow. Its tail is slightly forked and lacks the white spots found in some related species. Adults typically measure between 4.3 and 4.7 inches (11 to 12 centimeters) in length and weigh around 14 to 17 grams. The bill is short, broad, and black, matching the color of its legs. Sexual dimorphism is minimal; females are slightly duller on their upperparts, while juveniles are overall matte grayish-brown above, with less defined white wing markings and a light grayish wash across the breast.

Geographical distribution It is widely distributed throughout the lowlands of South America. Its geographic range extends from northern areas in Colombia, Venezuela, Trinidad, and the Guianas, southward through the vast Amazon Basin of Brazil, eastern Ecuador, Peru, and Bolivia, reaching Paraguay and northern Argentina. While most populations are resident throughout the year, those inhabiting the southernmost limits of the range may perform seasonal northward migrations during the austral winter months.

Habitat: It is strictly associated with lowland freshwater bodies and humid environments, rarely occurring far from water. Its preferred habitats include large rivers, lakes, lagoons, marshes, flooded savannas, mangroves, and artificial reservoirs. It favors open areas containing dead standing trees, fallen logs, or floating vegetation, which provide essential perches for resting and territorial scanning. It is primarily restricted to elevations below 1,600 feet (500 meters) above sea level, although minor populations occasionally occur in low Andean valleys.

Feeding Its diet is exclusively insectivorous. It captures its prey on the wing, performing swift, highly maneuverable aerial acrobatics just inches above the water´s surface. It feeds on a wide variety of small flying insects, including dipterans, coleopterans, hymenopterans such as winged ants and wasps, and ephemeropterans. On occasion, it may hover briefly to glean insects directly from the water surface or emergent aquatic vegetation.

Behavior: It is a highly active, diurnal species that is typically encountered in pairs or small family groups. Unlike many other swallow species, it does not form large, communal flocks outside the breeding season, preferring a more dispersed social structure. Its flight style is graceful, combining rapid wing beats with short periods of gliding. It is highly territorial during the breeding season, vigorously defending the immediate vicinity of its nest site against rivals and other bird species.

Nesting Breeding periods vary depending on regional rainfall patterns, usually coinciding with the transition from the wet to the dry season when insect abundance peaks. It builds its nests in pre-existing cavities, such as natural hollows in dead trees standing in water, abandoned woodpecker holes, rock crevices, or human structures including pipes, bridge crevices, and fence posts. The inner cup is lined with dry grasses, rootlets, and a thick lining of soft feathers often gathered in flight from the water. Females lay a clutch of 3 to 4 pure white eggs. Incubation is carried out primarily by the female and lasts around 15 to 16 days. Both parents actively participate in provisioning and protecting the chicks, which fledge approximately 20 days after hatching.

Conservation status It is currently evaluated as Least Concern (LC) on the IUCN Red List of Threatened Species. The global population is considered stable, supported by its extensive geographic distribution and its ability to adapt to human-altered environments for nesting. Nevertheless, local populations face potential threats from the loss of riparian vegetation, chemical pollution of waterways due to agricultural and mining activities, and the destruction of critical wetland habitats.