Sick’s Swift
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Quick Facts
- Scientific Name: Chaetura meridionalis
- Spanish Name: Vencejo de Sick
- Family: Apodidae
- Known Nicknames: Sick's Swift
- Average Length: 12–13 cm / 4.7–5.1 in
- Average Weight: 18–25 g / 0.63–0.88 oz
- Wingspan: 30–32 cm / 11.8–12.6 in
- Key Feature: Forked tail and uniformly dark brown plumage with a pale throat patch
- Primary Diet: Insectivore
- Range: Central and eastern South America (Brazil, Bolivia, Paraguay, Argentina)
- Habitat: Open woodlands, savannas, and forest edges
- Social Structure: Highly Social (often seen in flocks with other swifts)
- Nesting/Breeding: Tree cavities or rock crevices
- Conservation Status: Least Concern (LC)
- Population Trend: Stable
The Sick's Swift (*Chaetura meridionalis*) is a master of the aerial realm, a cigar-shaped dynamo that spends nearly its entire life on the wing over South America. Distinguished by its sooty-brown plumage with a notably paler throat and a distinct, pale rump patch that flashes in flight, this swift is virtually never seen perched, possessing minuscule feet adapted only for clinging to vertical surfaces. Its most unique characteristic is a deeply forked tail with stiff, spiny feather shafts that it uses as a prop against cave walls and chimneys, where it nests in massive, noisy colonies. A true meteorological nomad, it is famous for its dramatic, long-distance migrations triggered by seasonal rains, often traveling in enormous, swirling flocks that darken the sky at dusk, and its high-pitched, chattering "sick-sick-sick" call—from which it derives its common name—echoes through the air as it hunts for flying insects with relentless, scimitar-like wingbeats.
Fun Facts
Sick's Swift is a master of aerial endurance, spending almost its entire life on the wing, even sleeping and mating in flight, and only landing to roost or nest. It possesses a unique adaptation: asymmetrical wing bones that allow it to twist and bank with incredible agility, snatching insects with its wide, gaping mouth like a living net. Quirkily, it builds its nest entirely from saliva, gluing twigs to the inside of hollow trees or chimneys, and the chicks cling to the vertical walls with specialized sharp claws, never truly sitting until they fledge.
Habitats & Distribution
Sick's Swift is found across a broad swath of central and eastern South America, from eastern Bolivia and central Brazil south through Paraguay, Uruguay, and into northern and central Argentina. Its geographical range is strongly associated with the South American summer breeding season, after which it migrates northward to winter in the Amazon Basin. The species primarily inhabits open and semi-open landscapes, including cerrado savanna, Pantanal wetlands, gallery forests, and agricultural areas, often roosting and nesting in hollow trees or man-made structures like chimneys and bridges. It is rarely found within dense, continuous rainforest, instead favoring areas with scattered tall trees or human settlements that provide suitable vertical surfaces for nesting.
Behaviours & Reproduction
Sick's Swift is a highly social and gregarious species, often foraging and roosting in large flocks. Mating pairs form monogamous bonds for a breeding season, with courtship involving aerial chases and vocalizations. They typically nest in dark, sheltered cavities such as abandoned woodpecker holes, under eaves, or in chimneys, constructing a shallow cup of twigs and saliva glued to a vertical surface. A unique reproductive strategy is their use of a single, relatively large egg per clutch, which both parents incubate for about 17–19 days. The chick, which is altricial and brooded continuously for the first week, is fed by both adults via regurgitation until fledging at around 28–30 days. This low clutch size is offset by high parental investment and the ability to re-nest if the first attempt fails, with pairs sometimes raising two broods in a season where conditions allow.
Diet
The diet of Sick’s Swift (Chaetura meridionalis) consists almost exclusively of flying insects, which it captures entirely in mid-air during sustained, rapid flight. This species is an obligate aerial insectivore, meaning it never lands to forage; instead, it sweeps through open skies with its mouth agape to snatch prey. A fascinating aspect of its feeding behavior is its strong reliance on social foraging, often joining mixed-species flocks of other swifts and swallows to exploit dense swarms of insects, particularly during the rainy season when termites and ants perform nuptial flights. Their diet is heavily seasonal, shifting from a variety of beetles, flies, and wasps in the breeding season to a near-total dependence on flying ants and termites during migration and winter, a strategy that allows them to track ephemeral insect blooms across vast distances. Additionally, Sick’s Swift has been observed drinking on the wing by skimming its lower mandible across the surface of rivers and lakes, a rare behavior for a swift that also helps it ingest small aquatic insects.
Colors
Sick's Swift (Chaetura meridionalis) is predominantly dark sooty-brown above, with a slightly paler grayish-brown throat and breast, and a whitish-gray patch on the rump. Its wings are long, narrow, and sickle-shaped, lacking any distinct markings, and the body is uniformly dull without bold patterns, providing camouflage against the sky and tree bark.
Distribution Map
Places linked to this species. A sighting is never guaranteed.
