Sick's Swift Chaetura meridionalis Scientific name definitions

Until recently, the so-called Ashy-tailed Swift was considered one of the more widespread species of Chaetura swifts found solely in the Neotropics. However, within the last two decades new research has demonstrated that the two subspecies included within Ashy-tailed Swift were not only different species, but that the form breeding in eastern Venezuela was best treated as a subspecies of Vaux’s Swift (Chaetura vauxi). This left Chaetura meridionalis, which breeds in southeastern South America in the austral summer, and winters principally in northern South America, in need of a new vernacular name. Sick’s Swift commemorates the German-born ornithologist, Helmut Sick, who spent most of his adult life in Brazil studying the country’s birdlife. This mid-sized Chaetura is most distinctive on account of its shape, short-tailed with a bulging midwing; the plumage is entirely brown. In terms of its relationships, it seems that Sick’s Swift is perhaps more closely related to the North American-breeding Chimney Swift (Chaetura pelagica) than to the Vaux’s Swift.

11·5–13·5 cm; mean 21·5 g, one female 19·5 g. Medium-sized swift with short square tail between <em>C. brachyura</em> and other Chaetura in length, and rectrix spines 2 mm beyond web; protruding head and distinctive wing shape, hooked in outer wing and with bulging midwing cutting in at body. Adult  has lores, forehead and crown and ear-coverts grey-brown glossed olive, black eye-patch, pale grey-brown throat (sometimes whitish  ) looking darker when worn, nape and mantle uniform with upper head, upper back paler brown and grading even paler onto uppertail-coverts, with grey-brown tail (paler than remiges), even paler on underside  with short spines (longest on central rectrices), while the underparts grade darker from throat to belly, becoming paler grey-brown again on undertail-coverts; typically uniform black-brown upperwing (darker than adjacent body), darkest on outer primaries and palest on secondaries, and coverts become progressively darker towards smaller feathers; underwing more contrasting, with clearly paler remiges and darker coverts. Bare parts: tarsus dark reddish brown, bill black, and iris greyish brown. Juvenile  much like adult, but has distinct narrow white tips to inner primaries, secondaries and tertials.

E & SE Bolivia, SE & S Brazil, Paraguay and N Argentina; winters N to Panama, Colombia and French Guiana.

Variously described as a low-pitched “chu-chu-chu-chu” preceded by a rattling chipper (Paraguay), or an excited, rapid, chattering  “see tsdee ts tsee tsee tsee” (Brazil), or a “tli-ti-tit” (song) and “tip tip tip” (call), both from Brazil. Structure quite similar to that of C. pelagica, but descending phrases more tinkling, less burry. Young in nest produce soft chirps like the tinkling of a little bell, as well as noisy begging notes.

Season reported Oct–Nov, in Mato Grosso, late Aug–Jan, in S Brazil, and Sept–Mar in SE Brazil, laying in late Nov in São Paulo. Nests  singly, commonly placed in chimneys or under eaves of buildings  (especially in urban S & SE Brazil, since late 1940s), but also in hollow trees, such as Mauritia (buriti) palms (e.g. in Minas Gerais and Goiás), and also in an abandoned well > 25 m below ground (Bahia), showing an unknown degree of site fidelity; in buriti palm, nest a half-cup  of leaf stalks and palm fibres sealed with saliva to vertical wall  , reused until it collapses, then rebuilt in same location, but small sticks  reported in chimney nest; material may be collected from trees in flight, using feet; measures 85 mm wide by 37 mm deep and 43 mm front to back. One tree cavity nest was 12 m above ground. Clutch  3–4 (occasionally five) white eggs, but one brood of nine apparently being fed by more than one female; size reportedly 17·5–20 mm × 13–14 mm; incubation period unknown, but fledging period c. 35 days, although both adults feed young  , initially up to 61 times daily, less as young mature. Probably single-brooded, at least in parts of range.