UTILITY OF BIRDH IN NATURE. 



.sued li-oiii afar by others still, until a feathered host eo.i- 

 ceiitcrs from the sky upon the carrion feast. 



Bii-ds are lower in the organic scale than the class of 

 iiiainnials which includes man, the fcmr-footed animals, and 

 even the seal and the whale. Birds are closely allied in 

 structure to reptiles. The earliest bird known, the Arcli:e- 

 opteryx, had teeth, 

 two fingers on each 

 Aving, and a long rep- 

 tilian tail adorned 

 witli feathers. Still, 

 notwithstanding the 

 comparatively low 

 l)]ace which is given 

 by the sA^stematists 



to birds, their 

 })hysical organiza- 

 tion excels in some 



respects that of all 



other an imals. Th e y 



surpass all other 



vertebrate animals 



in bi-eathing ])ower 



or lung cai)acity, as 



well as in nmscular 



strength and activ- 

 ity-. The tempera- Fig. l.-Tl,e An-lueopteryx. u ),inl witl, teeth. Re- 



ture of the blood is stored IVom the Jurassic epocli. A l)out une-lilth natural 



, . , . , . , sr/A'.; after Chapiuau. 



higher in birds than 



in other animals, and llu; circulation is more rapid. To 

 maintain this high temperature, rapid circulation, and great 

 activity, a large amount of food is absolutcdy necessary. 

 Food is the fuel without which the brightly l)urning fires 

 of life must grow dim and die away. BirdJ^ are, therefore, 

 fitted for their function of aerial i)olice not only by their 

 powers of flight and perception, but also by their enormous 

 capacity for assimilating food. Wlien food is i)lentiful, 

 birds gorge themselves, accumulating fat in (juantities. 

 Shore birds frequently become so fat during the fall migra- 



