138 VERTEBRATES: BIRDS. 



The Genus Polyborus is characterized by rather long 

 bill, long, pointed wings, long and rather slender tarsi, 

 and rather weak claws. 



The Mexican Eagle or Caracara Eagle, P. tJiarus, Cass., 

 of Southern North America and of South America, is 

 sluggish in its habits, and walks on the ground with fa- 

 cility. 



The Genus Craxirex has the edges of the upper man- 

 dible festooned. 



Harris's Buzzard, C. unicinctus, Cass., of Southern North 

 America and of South America, is twenty-two to twenty- 

 four inches long, the body dark brown, shoulders, wing 

 coverts, and tibiae reddish-chestnut, and the tail white at 

 the base and tippjed with white. 



STRIGID/E, OR OWL FAMILY. This Family comprises 

 all the nocturnal birds of prey. They are characterized 

 by a short heavy form, large head, large eyes directed for- 

 ward, curved bill nearly concealed by bristle-like feathers, 

 large ear-cavities, and face encircled by a disk of short 

 rigid feathers, which, with the large eyes, give to these 

 birds an expression very much like that of a cat. This 

 family is represented in all parts of the world. About 

 one hundred and fifty species are known, forty of which 

 belong to America. 



The Genus Strix is characterized by rather small eyes, 

 and conspicuous facial disc. It contains twelve species. 



The Barn Owl, .S. pratincola, Bonap., of all temperate 

 North America, sixteen inches in length and the wing 

 thirteen, is our only representative of this genus. It is 

 found near the borders of the forest, and frequently re- 

 sorts to old buildings in its search for rats and mice. 



The Genus Bubo Great Horned or Cat Owls is 

 characterized by large size, robust and powerful form, 

 conspicuous ear-tufts, and very large eyes. There are 

 about fifteen species of this genus. 



