The Bird Department 



Bv A. A. Allen. Ph.D. 

 Assistant Professor of Ornithology, Cornell University 



THE IMPLEMENTS OF BIRDS 



PASSING through the halls uf any of our large 

 museums and inspecting the cases in which are 

 arranged the mounted birds from all over the 

 world, one is impressed by the great variety of their form 

 and color. Almost every imaginable combination of 

 colors is found represented in the iilumage of some bird. 



HEAD OF A RED-TAH.Kn HAWK 



A bill sucli as this is well adajjted to a diet of birds and small mam- 

 mals, and has been copied by the totally unrelated owls and shrikes. 



and the many modifications of size and shape are such as 

 to leave one confused by the heretogenous assemblage. 

 One is almost led to believe that nature has given loose 

 rein to her imagination and allDwed her most fantastic 

 dreams to take the form of birds. Yet scientists tell us 

 that there is a reason for everything, that no structure 

 exists unless perfectly adapted to the function which it 

 has to perform. The long legs, slender neck and the 

 great humped bill of the flamingo, we are told, are 

 adapted to its peculiar method of feeding on the minute 

 mollusc life of the tropical mud flats where it lives. The 

 tremendous bills of the South .American toucans and 

 African hornbills serve as arms for reaching far out to 



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the smaller branches for the fruits which form the food 

 for these ungainly creatures. But let us consider the 

 commoner of our North American birds with reference 

 to their food and see if there are similar reasons for 

 their variety of form. 



The birds of prey, with their long, hooked bills, sharp 

 trdons, and powerful wings fitted for the pursuit of birds 

 and small mammals, are doubtless familiar to everyone. 

 So necessary is this type of bill and foot for a carnivor- 

 ous diet that tw'o totally unrelated groups of birds, the 

 hawks and the owls, having the same feeding habits, have 

 developed such similar structures that for many years 

 they were classified together as forming the Order 

 Raptores, when, as a matter of fact, the owls are nuich 

 more closely related to the whip-poor-wills. 



One group of the common perching birds, the shrikes, 

 which have taken up a carnivorous diet, have likewise 

 developed hawklike bills, although their feet are still 

 of the ordinary perching type. The buzzards, on the 

 other hand, which have degenerated from the carnivor- 

 ous diet to one of carrion, wdiile retaining the strong 

 hooked bill for rending flesh, have lost the powerful 

 talons and the accompanying strength of limb, so that 

 now they even spring from the ground with difficulty. 



But if one examines more closely such a group of birds 

 as the hawks, all having the same type of food, one dis- 

 covers dii¥erences of form of body according to their 

 method of securing their prey. There are. for example. 



A I'liaj-DlLl.l'D GREBE 

 The grebes dive for their fish and pursue them under water. Their 

 powerful legs, with large lohed toes, are placed so far back that, 

 although they are most graceful on the water, they are practically 



