20 SULID^ SULA 



not return till they are quite adult. The old birds leave the islands 

 in April or May, returning again in July or August. 



The food of the Malagash consists entirely of fish, which they 

 must consume in enormous quantities. They have a harsh, raucous 

 cry " carra carra " both vyhen flying and when seated on their 

 nests. 



The guano produced by these birds and by the Trek Duiker, 

 which as a tule do not nest on the same islands, is collected after 

 the breeding season is over, every year, and forms a valuable asset 

 to the Government of Cape Colony. It is sold to the farmers at 

 about cost price. 



570. Sula cyanops. Masked Booby. 



Dysporus cyanops, Sundev., Physiogr. Sdllshapets Tidsk. i, p. 218, 



pi. V (1837). 

 Sula cyanops, Grant, Cat. B. M. xxvi, p. 430 (1898) ; Reichenotv, Vog. 



Afr. i, p. 84 (1900). 



Description. — General colour white except the quills, greater 

 coverts and tail-feathers, which are blackish brown ; chin and throat 

 quite naked, but the bare space not extending as a narrow band 

 down the front of the neck ; tail-feathers sixteen or sometimes 

 eighteen in number. 



Iris yellow ; bill horn coloured, yellowish or greenish ; naked 

 skin on the throat bluish-black to dark slate, legs and feet greyish. 



Length about 36; wing 17'6; tail 7'3 ; culmen 4-3 ; tarsus 2-3. 



The young birds are smoky-brown above, with a few white 

 feathers and pure white below. 



Distribution. — This species is found throughout the tropical 

 portions of the Atlantic, Pacific and Indian Oceans, and breeds 

 chiefly on oceanic islands. 



Its inclusion in the South African fauna rests on a record in the 

 British Museum Catalogue in which an example obtained " at sea, 

 off the Cape of Good Hope" is noted. It is a common bird on 

 Ascension and nests on Boatswain Bird Island close by, whence a 

 series of specimens, obtained by Sir David Gill, is now pre- 

 served in the British Museum. In the Indian Ocean it has been 

 found breeding on Farquhar Island between the Seychelles and 

 Mauritius, by Capt. Farquhar, E.N. {Ibis, 1900, p. 63). 



