The Crested Swifts form a subfamily composed of a single genus, distinguished by their short naked tarsi, and by the wings when folded not extending or scarcely extending beyond the tail. There are, however, several other characters of importance. The plumage is softer than in other Swifts, and there is a patch of silky downy feathers on each flank. The sexes differ, and the plumage of the nestling is unlike that of the adults, both characters not found in other members of the family. The sincipital feathers are more or less elongated and erectile; in some species there are also elongate superciliary or moustachial tufts. The tail is long and forked. The hind toe is not reversible. The posterior portion of the sternum has two foramina, one on each side.
Quite recently, too, it has been shown by Mr. P. A. Lucas (Ibis, 1895, p. 300) that the deep plantar tendons in Macropteryx coronata differ from those of other Cypseli. The flexor longus hallucis gives off a slip to the hallux (which is not supplied by the f. perf. digitorum), and then goes on to blend, not with the f. perf. digitorum as a whole, but with that branch of it which goes to supply the fourth digit.
The nidification on trees is described under M. coronata. Only a single egg is laid. The genus is found in the Oriental region and Papuasia, three species occurring within our limits.
Key to the Species.
a. Sincipital crest long; no superciliary or moustachial tufts.
a1. Back bluish grey……………….M. coronata, p. 180.
b1. Back greenish bronze……………….M. longipennis, p. 181.
b. Crest smaller; white superciliary and moustachial stripes elongated into tufts behind……………….M. comata, p. 182.