CHAPTER II. 



THE LIVING BIRD. 



Faetors of Evolution. — If wliile in the fields we ob- 

 serve birds with an appreciative eye, we sliall soon be 

 impressed with the great diversity sliown in their struc- 

 ture and habits. The Fisli Hawk pUinges from the air 

 into the water and grasps its prey with merciless talons. 

 The Hummingbird daintily probes a flower. The Wood- 

 pecker climl)s an upright trunk, props itself with its 

 stiff, pointed tail-feathers, while with its chisel-shaped 

 bill it excavates a grub and then impales it with its 

 spearlike tongue. These birds tell us a wonderful story 



Fig. 2. — End of spearlike tongue of Pileated Woodpecker. (Much enlarged.) 



of adaptation to the conditions of life, and, knowing that 

 they have descended from a common ancestor, we ask, 

 " Wliv do they now differ so widely from one another ? " 

 Biologists the world over are trving to satisfactorily 

 answei' this question, and it is impossible for me to 

 even mentii>n here all the theories which they have 

 advanced. However, some knowledge of the most im- 

 portant ones is essential if you would study the relation 

 between the bird and its haunts and habits. The Dar- 

 win-Wallace theory of iSTatural Selection, in more or less 



14 



