The Lesser Frigatebird, Fregata ariel, is a species of frigatebird.
It nests in Australia, among other locations.
There is a single record from the Western Palearctic, from Eilat in
the Gulf of Aqaba.
The Lesser Frigatebird or Least Frigatebird (Fregata ariel) is said
to be the most common and widespread frigatebird in Australian seas
(Lindsey,1986). 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.
It is the smallest of the three frigatebirds found in Australian
waters, measuring about 75cm (30 in) in length. 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 which 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. Their name probably derives from the fact that they harass
other sea birds such as boobies and tropic birds as they
return to their nests from feeding, forcing them to disgorge their
catch, which is then swooped upon and caught by the frigate birds before
it reaches the water below. This practice seems to be more common
amongst female frigate birds, but probably only accounts for a fairly
small proportion of the diet, which mainly consists of squid and flying
fish scooped up from the surface of the sea.
Breeding seems to occur between May and December in in the Australian
region. They nest in trees (on Christmas Island) and both sexes
contribute to nest building and incubation and feeding of the young. One
egg is laid which takes 6-7 weeks to hatch. Fledglings are not left
alone for another seven weeks or so for fear that they may be attacked
and eaten by other birds including other frigate birds. They remain in
the nest for another 6 months or so until fledged but they are cared for
and fed by their parents for quite a long time after that.