THE STRUCTURE OF THE BIRD 19 



9. The bill of the Woodpecker may be compared to 

 the adze which the Carpenter uses for chipping beams 

 of wood. It is only by means of hard blows that this 

 bird can get at the worms which it finds in decaying 

 wood. 



10. The Duck's bill, on the other hand, is flat toothed 

 at the side, exactly formed for straining the food which 

 it gets out of the water. 



1 1 . The bill of the Gull is so formed that it can easily 

 take up food from the surface of the water. Where 

 Gulls arrive in large flocks, they eagerly follow the 

 plough in the fields, and are then of great benefit. 



12. The bill of the Crossbill is a valuable tool, with 

 which he is able to pick out the seeds from between the 

 scales of the fir cones. 



13. The Ortolan splits hard seeds with the arch and 

 the notch in its beak, as it were with nut-crackers. 



14. The bill of the Avocet is in shape the opposite 

 of the Curlew, that of the former curving upwards, of 

 the latter downwards. 



Thus we see that as with the wing, so with the bill, 

 each bird is furnished with the kind that is most suitable 

 to its nature and habits. 



The general law of adaptability to its purpose is also 

 strikingly exemplified in the formation of the foot. Let 

 us look at Plate X. 



1. The foot of the Fieldlark has a spur-like nail on 

 the back toe which is nearly straight, so that the bird 

 can easily rest on the ground. 



2. The Pheasant's foot is just like that of the Hen; 

 which enables it to walk and run. 



3. The powerful, sharp claw of the Eagle strikes 

 deeply into the flesh of its prey and holds it fast. 



