Very large with very long narrow pointed wings (spread up to 7½ ft), bent back at the 'shoulder', and long deeply forked tail (often folded so as to appear pointed). Adult male entirely black with red throat pouch, which is inflated like a balloon in breeding season (often not apparent at other times). Adult female also mostly black (including throat), but lacks throat pouch and has sides of neck and entire breast white, and brown band on upper wing-coverts. Immature resembles female but in addition has entire head white.
Habits and Behavior
Generally seen soaring high overhead on motionless wings, sometimes in very large congregations, particularly over its nesting and roosting islands.