THE WORLD'S BIRDS. 45 



allied to the Hazel-hen {Tetrastes honasia) of the 

 Old World, but has a frill of purple-black feathers 

 on each side of the neck. It is often called " Phea- 

 sant " or " Partridge." The Prairie-hen {Tym- 

 panuchus americanus) is a brown, barred bird, with 

 a pair of wing-like appendages on the neck, and is 

 widely spread in open country in North America. 

 The largest American Grouse is the Sage-cock 

 (Centrocercus urophasianus) of the barren eastern 

 plains ; it has a long tail of pointed feathers. 



Many game-birds have been acclimatized in 

 other countries, especially the Pheasants ; owing 

 to their limited powers of flight they are easy to 

 establish, but on account of their quarrelsome 

 nature two species of the same size will seldom 

 live side by side. 



Gannets {Sulidce). 



Diagnosis. — Sea-fowl with straight bills, with no per- 

 ceptible nostrils, all four toes webbed, and long 

 wings. 



Size. — From that of a goose to that of a duck; 



Form. — Bill stout, straight, slightly curving towards 

 tip, the covering grooved, nostrils obsolete, corner 

 of mouth reaching beyond eye ; feet with short 

 shanks and all four toes webbed, the first pointing 

 inwards or backwards ; wings longj pointed ; tail 

 moderate, pointed ; neck long. 



Plumage and Colouration. — Feathering white or 

 brown ; no sexual difference or seasonal change ; 

 but young different from adults, being darker. 

 Face always more or less bare. 



Young. — Helpless, and fed by parents ; at first naked, 

 then clothed in thick white down. 



