Birds of America
By John James Audubon, F. R. SS. L. & E.
FAMILY V. CYPSELINAE. SWIFTS.
Mouth opening to beneath the hind part of the eyes; bill extremely short,
very broad at the base, compressed at the end; upper mandible decurved at the
point, the edge inflected, with an indistinct sinus. Nostrils basal,
approximate, oblong. Head large and depressed; neck short; body rather slender.
Feet extremely short; tarsus rounded, destitute of scutella; toes extremely
short, the three anterior nearly equal; hind toe very small, and versatile;
claws strong, compressed, arched, very acute. Plumage compact; no bristles at
the base of the upper mandible; wings extremely elongated, falciform, the first
quill longest; tail of ten feathers. OEsophagus of moderate width, without
crop; stomach oblong, moderately muscular, with a dense rugous epithelium;
intestine short, and rather wide; no coeca. No inferior laryngeal muscles.
Nest in crevices or holes, or attached to high places. Eggs elongated, white.