532 ORNITHOLOGY AND OOLOGY. 



SUB-ORDER GAVLE. 



1 FAMILY SULIDJE. THE GANNETS. 



Bill rather long, straight, sides compressed, very strong, tapering to the point, 

 which is a little decurved; nostrils hardly observable; wings very long; tail long 

 and cuneate; toes long, and all joined by full webs; gular sac moderate. 



SULA, BRISSON. 



Sula, BRISSON, Ornith. (1760). (Type Pelecanus bassanus.) 



Bill rather longer than the head, straight, stout at the base, with the sides com- 

 pressed, grooved near the tip, which is a little curved, the cutting edges serrated 

 irregularly; nostrils basal and scarcely perceptible; wings lengthened; tail rather 

 long and much graduated; tarsi short and stout; toes long, and joined together by 

 full webs; claws moderate, the middle one serrated; gular sac rather moderate. 



These birds usually frequent almost inaccessible rocky islands, where they con- 

 gregate in great numbers during the season of reproduction, at other times migrat- 

 ing along the coast. Their flight is rapid, powerful, and long-continued. 



SULA BASSANA. Brisson. 

 The Common Gannet; Solan Goose. 



Pelecanus bassanus, Linnaeus. Syst. Nat. (1766), 217. 



Sula bassana, Nuttall. Man., II. (1834) 495. Aud. Orn. Biog., IV. (1838) 222. 

 Ib., Birds Am., VII. (1844) 44. 



DESCRIPTION. 



General color of the plumage white; bill bluish-gray; bare space around the eye 

 and on the throat blackish-blue ; primaries brownish-black, first longest. 



Adult. The color of the plumage generally is white, the head and hind neck 

 being of a fine buff-yellow ; alula and primaries brownish-black ; shafts white for 

 about two-thirds their length from the base, thence gradually becoming dark-brown ; 

 bill pale bluish-gray, greenish at the base, the lines on the upper mandible blackish- 

 blue; bare space in the region of the eye, and down the centre of the throat 

 blackish-blue; iris white; tarsi, toes, and their webs, blackish-brown; the lines of 

 scutellse on the tarsi and toes green ; claws bluish-white. The female resembles the 

 male, but is rather smaller. The young have the head, neck, and upper plumage 

 dark-brown, each feather terminating with a triangular white spot ; under plumage 

 grayish-white, the feathers broadly margined with grayish-brown. 



