(2184) Sula leucogaster plotus.
THE BROWN GANNET.
Pelecanus plotus Forster, Descript. An., p. 278 (1844) (New Caledonia). Sula leucogaster. Blanf. & Oates. iv. p. 346.
Vernacular names. None recorded.
Description. Whole head and neck, upper plumage, wings and tail chocolate-brown; median under wing-coverts white, others brown ; lower plumage and axillaries pure white.
Colours of soft parts. Iris silver-grey; bill and orbital skin yellow; legs and feet pale yellow. Tail-feathers sixteen to eighteen.
Measurements. Wing 386 to 414 mm.; tail 188 to 197 mm.; tarsus about 45 to 50 mm.; culmen 93 to 101 mm.
Young birds have the upper parts, head and neck much paler brown; the white on the lower parts is replaced by pale smoky-brown, most of the feathers white-edged.
Nestling in down pure white.
Distribution. North-East and North-West Australia through the Austro-Malayan islands to Malacca, once to the Laccadives.
Nidification. Macgillivray found this Booby breeding on an island off New Holland and describes the nests as ill-made heaps of herbage with hardly any cavity and, generally, containing two eggs. On the Great Barrier reefs other colonies were observed. Many birds bred in immature plumage, as do all the Gannets.
This species is said not to attempt to defend young or eggs when molested but to move off quickly with merely a protesting croak or two.
The few eggs I have seen of this subspecies are very much like those of Cormorants in texture etc. but broader in proportion; the real colour is a pale blue but this is overlaid with a thick covering of calcium, white when fresh but soon discoloured and dirty. Seven eggs average 59.7 X 40.4 mm.: maxima 64.0 x 40.1 and 60.0 x 42.3 mm.; minima 56.0 x 41.7 and 59.3 x 26.6 mm.
Habits. The Booby frequents small islands and rocky sea-coasts in large colonies, living on fish, cuttlefish etc The fish it usually takes by diving when swimming but sometimes by diving into the sea from some height as it flies along. Its flight is very strong and consists of alternate flappings and sailings with stiff outspread wings. In many places it is said to be extremely fearless, having to be forced off its eggs or young, whilst on Darnly Island it is said to be commonly lamed, the birds fishing for their own food and then returning to the huts of their respective native owners. Its call is a loud, harsh croak. Its occurrence in India is casual only but it has been obtained in Ceylon and has been frequently seen off the coasts of Eastern India and Burma.