Blue-and-white Swallow

Quick Facts

Migratory
  • Scientific Name: Pygochelidon cyanoleuca
  • Spanish Name: Golondrina azuliblanca
  • Family: Hirundinidae
  • Known Nicknames: Blue-and-white Swallow, Golondrina Azul y Blanco
  • Average Length: 11–13 cm / 4.3–5.1 in
  • Average Weight: 10–18 g / 0.35–0.63 oz
  • Wingspan: 28–33 cm / 11–13 in
  • Key Feature: Iridescent blue-black upperparts contrasting with white underparts and a shallowly forked tail
  • Primary Diet: Insectivore
  • Range: Central and South America from Costa Rica to Tierra del Fuego, including Trinidad and Tobago
  • Habitat: Open and semi-open areas near water, including farmland, grasslands, and urban areas
  • Social Structure: Highly social, often in small flocks or mixed-species groups
  • Nesting/Breeding: Cavities in banks, cliffs, walls, or under bridges; occasionally in tree holes
  • Conservation Status: Least Concern (LC)
  • Population Trend: Stable

The Blue-and-white Swallow (*Pygochelidon cyanoleuca*) is a sleek, agile aerialist found from Costa Rica to the southern tip of South America, easily identified by its striking contrast of glossy steel-blue upperparts and pure white underparts extending to the undertail coverts. Its most distinctive feature is a deeply forked, almost scissor-like tail, which it uses to perform breathtaking, erratic maneuvers while hawking insects close to water or open fields. Unlike many swallows, this species often nests in small colonies on human-made structures like bridges and buildings, where its soft, chattering song and acrobatic flights make it a familiar and engaging neighbor in both rural and urban landscapes.

Fun Facts

Despite its delicate appearance, the Blue-and-white Swallow is a master of aerial acrobatics, capable of catching insects mid-flight with its beak while also using its feet to snatch prey, a rare technique among swallows. It has a quirky habit of roosting communally in large numbers, sometimes packing into a single nest box or crevice so tightly that they pile on top of each other for warmth. During breeding season, pairs engage in a rapid, synchronized "sky dance" where they chase each other in tight spirals, occasionally locking beaks in midair. Remarkably, this species is one of the few swallows that regularly nests in human structures like bridges and eaves, adapting so well to urban areas that it often prefers concrete ledges over natural cliffs.

Habitats & Distribution

The Blue-and-white Swallow occupies a broad range of open and semi-open habitats, from sea level up to elevations of 4,000 meters. It is commonly found in agricultural areas, grasslands, savannas, river valleys, and urban settings, often perching on wires or buildings. Its geographical range spans much of South America, from southern Costa Rica and Panama through the Andes of Colombia, Ecuador, Peru, and Bolivia, then extending across Brazil, Paraguay, Uruguay, and Argentina, with populations wintering in the Amazon basin and migrating south to Patagonia and Tierra del Fuego.

Behaviours & Reproduction

Highly social and often found in small, loose colonies, the Blue-and-white Swallow engages in cooperative breeding, where non-breeding helpers, often offspring from previous broods, assist the breeding pair with nest defense and feeding chicks. Mating pairs are monogamous for a season, forming through aerial chases and mutual perching displays. They nest in cavities, including burrows in riverbanks, crevices, or human structures, lining them with grass and feathers. A typical clutch consists of 3 to 5 white eggs, with both parents sharing incubation for about 15 days. A unique strategy is their use of old nests from other birds, such as horneros or woodpeckers, reducing construction effort. Fledging occurs around 22-26 days, and the young may return to help raise subsequent broods, enhancing the pair’s reproductive success in variable environments.

Diet

The Blue-and-white Swallow is an aerial insectivore, meaning it captures all its food while in sustained flight, typically foraging over open areas like fields, rivers, and forest clearings. Its diet consists almost exclusively of small, flying insects, with a particular preference for flies (Diptera), ants (Hymenoptera), and beetles (Coleoptera), though it will also consume moths, bugs, and termites. An interesting aspect of its feeding behavior is its reliance on “aerial plankton,” a term for the diverse cloud of tiny arthropods that drift in the air column, which the swallow exploits by flying with its wide gape open, often in mixed-species flocks. Unlike many swallows that feed primarily at dawn and dusk, this species is known to forage throughout the day during the breeding season to meet the high energy demands of its chicks, and it will adjust its hunting altitude based on weather, flying higher on warm days and lower during cool, damp conditions when insects are closer to the ground.

Colors

The Blue-and-white Swallow has a striking contrast of deep steel-blue upperparts, including the crown, back, wings, and tail, against pure white underparts from the chin to the belly. Its most unique marking is a sharply defined black mask extending from the bill through the eye, and a white crescent-shaped patch on the flanks is visible in flight. The tail is slightly forked with white inner webs on the outer feathers. It lacks specific camouflage adaptations, instead using its bright coloration for social signaling and aerial agility to avoid predators.