Grey-rumped Swift

The Grey-rumped Swift, known scientifically as Chaetura cinereiventris, is a small, agile bird, approximately 10.5 cm in length and weighing around 17 grams. It is characterized by its protruding head, short square tail, and distinctive wings that are both bulging in the middle and slightly hooked at the ends. The plumage of adults is predominantly glossy black on the upperparts with a contrasting wide gray rump and uppertail coverts, while the underparts are a lighter shade of gray.

Identification Tips

When identifying the Grey-rumped Swift, look for its glossy black upperparts and the namesake grey rump which is quite conspicuous. The bird's underparts are a paler gray, with the undertail coverts being darker. Juveniles resemble adults but have pale fringes on their wing feathers. The swift's flight is rapid and direct, with quick wingbeats, aiding in its identification.

Habitat

This species is quite adaptable, inhabiting a range of environments from lowland tropical evergreen forests to montane regions, and even secondary forests. It can be found from sea level up to elevations of 1,800 meters.

Distribution

The Grey-rumped Swift has a broad distribution across the Americas, from Honduras through South America, excluding Chile, French Guiana, Suriname, and Uruguay. It is also present in Trinidad and Tobago, and on the island of Grenada.

Behaviour

Grey-rumped Swifts are year-round residents throughout most of their range, with some evidence suggesting they may be breeding visitors in Paraguay and Argentina. They are often seen foraging in flocks, which can include a mix of swift species and sometimes swallows.

Song & Calls

The vocal repertoire of the Grey-rumped Swift includes a bright, repeated short 'tsip' and a series of slightly downslurred burry drawn-out notes that sound like 'trrreeew-trrreeew-trrreeew'. These calls are similar across the subspecies, with slight variations.

Breeding

Breeding seasons vary by location, with examples being September to March in southeastern Brazil and March to July in Costa Rica. The swifts construct half-cup nests on vertical walls within structures like chimneys. Both parents share incubation duties at night, though the incubation period and fledging time remain unknown.

Similar Species

The Grey-rumped Swift can be confused with other Chaetura species, but its wide grey rump and specific vocalizations are key differentiators.

Diet and Feeding

As aerial insectivores, Grey-rumped Swifts capture flying ants, bees, wasps, beetles, and flies while in flight. They are adept at foraging in flocks, which allows them to efficiently find and capture their prey.

Conservation status

The IUCN has classified the Grey-rumped Swift as Least Concern. With an estimated population of 50 million mature individuals and a vast range, the species does not face any immediate threats, although there is a slow decline in numbers. It is one of the most common Chaetura swifts within its range and is abundant in certain areas, with several populations residing in protected regions.