Sick’s Swift (Chaetura meridionalis) breeds from eastern Bolivia to northern Argentina and east-central Brazil, then moves north for winter. Specimen descriptions give adults a sooty-brown body and a pale throat. In central Argentina, two nests were recorded in tree hollows in Chaco woodland.
Hellmayr compared 13 specimens, including the type. He described adult crown and mantle as dark sooty brown, the back, rump, and upper tail coverts as pale grayish fawn, and the breast and belly as sooty brown with a faint bronze sheen; the whitish throat contrasts with the underside. He considered the bill heavier and the wings and tail appreciably longer than in Chaetura andrei. Juveniles were paler above, with little metallic sheen on the head and mantle.
Between 3 and 6 December 2015, two nests were found in hollows of white quebracho trees in Chaco woodland in central Argentina. One nest held three nestlings and the other five. This is a local breeding record from one site and period.
An extinction-risk assessment has not been added yet.