ANIMAL FLIGHT Il5 



flying birds, such as the condor, the Californian vulture, the 

 lammergeier, the griffon and brown vultures, all the larger eagles 

 and the ravens Uve in mountainous lands. 



The buoyant effect of wind blowing against a hill side is 

 easily appreciated by watching a turkey buzzard quartering 

 back and forth in his pecuHar see-sawing way without flapping 

 his wings, yet without losing altitude. 



Among the birds we And all possible gradations from birds 

 like the albatrosses, frigate-birds and chimney swifts, which 

 are almost always on the wing, through the majority of flying 

 birds to such forms as the tinamous and rails which very seldom 

 fly, to others, Hke the ostriches, that cannot fly at all, and 

 finally to those queer fossil birds with no trace of wings what- 

 ever. 



The flightless birds faU into three categories. First, birds 

 large, powerful or swift enough to outfight or to outdistance 

 any enemies, like the ostriches of Africa and Arabia, the rheas 

 of South America, the emus of Austraha, and the cassowaries 

 of Queensland, New Guinea and the Moluccas. Second, sea 

 birds frequenting regions where there are no beasts of prey, 

 like the penguins, the great auk, and the flightless cormorants 

 of the Commander Islands and the Galapagos. Third, land 

 birds Uving in regions from which predaceous beasts are ab- 

 sent, such as the dodo of Mauritius, the solitaire of Rodriguez, 

 the kiwis of New Zealand, the flightless rails of Oceania, etc. 

 Unless protected by most rigid laws such birds are doomed 

 whenever man penetrates their territory; if large they and 

 their eggs are eaten, and if small they soon become the victims 

 of the dogs, cats and rats which man always carries with him 

 in his wanderings. Thus the Commander Island flightless 

 cormorant, the dodo and the solitaire, and the great auk have 

 disappeared, and some of the other flightless birds are much 

 reduced in numbers. 



The penguins of the southern hemisphere and the great auk 

 have their wings so modified as to form long and powerful fins 

 with which they swim, after the manner of sea-turtles, and 



