2l6 SEA-BIRDS 



gullet of the loaded bird, which lays about with its long beak, hitting 

 those it does not approve of, and apparently trying to "clear the carpet" 

 for its legitimate family. 



Food is not carried in the pouch: this is used only for catching 

 the fish. After the gannet-like dive, which is spiralling like that of 

 the tropic-bird, the brown pelican appears at the surface quickly 

 (since' it makes a shallow dive and usually in shallow water), facing 

 the wind. Its first act on emergence is to drain the pouch of a gallon 

 or so of water by tilting the bill; this done, the bill is flung up, releasing 

 the fish, which is caught in the throat and swallowed — if it is not 

 snatched skilfully in mid-air by a gull or tern hovering near. 



The boobies are the tropical representatives of the gannets of 

 temperate waters, and although some workers prefer to separate them 

 generically, their life-histories are so similar that the field observer 

 accepts them readily under the genus Sula. Feeding and breeding 

 habits are identical in main features: incubation is by both sexes, the 

 young are born blind and naked, are fed by regurgitation, acquire a 

 first down of white colour, and remain in the nest for about three 

 months, being finally deserted by the adults. Three distinct species 

 (Fig. 38) breed in the tropical North Atlantic: the blue-faced booby 

 Sula dactylatra, breeding on the bare rock or cliff and making little 

 or no nest; the red-footed booby Sula sula, a tree-nester; and the 

 brown booby Sula leucogaster, nesting indiscriminately between these 

 extremes of habitat, usually on vegetation-covered ground, but also 

 in the open. All boobies feed largely on flying-fish, caught by diving, 

 gannet-fashion. Two eggs may be laid and hatched, but at North 

 Atlantic sites only one chick survives: the later-hatched one is starved 

 and trampled to death by the voracious appetite and activity of the 

 first-born.* Murphy (1936, p. 853) describes how the chick of S, 

 dactylatra gropes "far into the throat of the adult, where it remains for 

 a long time, picking and jabbing and pumping, in what looks like a 

 most uncomfortable manner, until all the available flying fish have 

 been extracted. The inordinate length of time devoted to the feeding 

 of the chick . . . may be still another reason why no food ever remains 

 in the gullet to profit the second oflfspring." One adult guards egg or 

 chick, but when the nestling is large enough to defend itself at a month 

 or so, the old birds leave it by day and go out on their excursions into 



*The Pacific representatives of the three boobies found in the North Atlantic, 

 however, often rear more than one chick, which may be due to the abundance of 

 fish food, especially in the Humboldt Current (Murphy). 



