Lesser Frigatebird

The lesser frigatebird is the smallest species of frigatebird and measures 66–81 cm (26–32 in) in length with a wingspan of 155–193 cm (61–76 in) and a long, forked tail. Male birds weight 625–875 g (1.378–1.929 lb). Female birds are heavier and weight 760–955 grams (1.676–2.105 lb). Like all frigatebirds, the male has a large, red sac on the front of the throat, which is inflated during courtship. Courtship display also involves a variety of calls, bill rattling, and spreading of the wings. The male is mostly all black save for a white patch on the flank that extends on to the underwing as a spur. Males also have a pale bar on the upper wing. Females have a black head and neck with a white collar and breast, as well as a spur extending on to the underwing. The female also has a narrow, red ring around the eye. Juveniles and immature birds are more difficult to differentiate, but the presence of the spurs of white in the armpits is a helpful distinguishing sign. Frigate birds are built for flying; they rarely swim and cannot walk, but can manage to climb around the trees and bushes in which they nest. They have a very light skeleton and long, narrow wings and are masters of the air. …

The lesser frigatebird is said to be the most common and widespread frigatebird in Australian seas. It is common in tropical seas, breeding on remote islands, including Christmas Island in the Indian Ocean in recent years. These birds are most likely to be seen from the mainland prior to the onset of a tropical cyclone, and once this abates, they disappear again.