248 CLASSIFICATION OF PLANTS AND ANIMALS 



The high temperature of the bird is a direct result of this rapid oxidation ; 

 furthermore, the feathers and the oily skin form an insulation which does not 



readily permit the escape of 

 heat. This insulating cover is 

 of much use to the bird in its 

 flights at high altitudes, where 

 the temperature is often very 

 low. Birds lay eggs and usually 

 care for their young. Over 

 13,000 species are named. 



SfomBch 

 -Liver 

 Pancreas 

 ^—Gizzard 



Intestine 



Classification of Birds 



Some of the internal organs of a bird. 



Divers and swimmers. Legs short, toes webbed. Examples: 



Like Gallinse, but with weaker legs. Examples : dove, pigeon. 

 Woodpeckers. 



gull, 



Obder 1. Rati' toe. Running birds 

 with no keeled breastbone. Ex- 

 amples : ostrich, cassowary. 

 Order 2. Pas'seres. Perching birds ; 

 having three toes in front, one be- 

 hind. Over one half of all species 

 of birds are included in this order. 

 Examples : sparrow, thrush, swal- 

 low. 

 Order 3. Galli'noe. Strong legs ; feet adapted to scratching. Beak stout. Examples : 



jimgle fowl, grouse, quail, domestic fowl. 

 Order 4. Rapto'res. Birds of prey. Hooked beak. Strong claws. Examples : eagle, 



hawk, owl. 

 Order 6. Natato'res. 



duck, albatross. 

 Order 7. Colum'boe. 

 Order 8. Pica'rioe. 



Two toes point forward, two back- 

 ward, an adaptation for climbing. 

 Long, strong bill. 

 Order 9. Psittaci (sit'a-si). Parrots. 



Hooked beak and fleshy tongue. 

 Order 10. Coccyges (kok-si'jez). 

 Climbing birds, with powerful 

 beaks. Examples : kingfisher, tou- 

 can, and cuckoo. 

 Order 11. Macrochires (mak-ro-ki'- 

 rez). Birds having long, pointed 

 wings, without scales on meta- 

 tarsus. Examples : swift, hum- 

 ming bird, and goatsucker. 

 Less common orders are not included 

 here. 



Mammals. — Dogs and cats, The bison, a grass-eating mammal, 



sheep and pigs, horses and cows, 



all of our domestic animals (and man himself) have characters of structure 

 which cause them to be classed as mammals. Mammals, like some other 

 vertebrates, have lungs and warm blood. Unlike all other vertebrates they 

 have a hairy covering ; nearly all bear young developed to a form similar to 



