BIRD ANATOMY 



By Sidney M. Bird 



Birds are highly specialized creatures and therefore 

 possess, in their physical construction, many arrangements 

 that are both unique and wonderful examples of fitness and 

 adaptability. Limited space compels us to select only the 

 most common examples that may be briefly described, be- 

 ginning with the bill. 



This instrument is hand and mouth in one. As hand, it 

 takes, holds and carries food or other substances, and in 

 many cases feels; as mouth it tears, cuts and crushes, acting 

 as both lips and teeth, neither of which birds possess. The 

 general shape of the bill may be likened to a cone. This 

 shape gives the greatest strength combined with the greatest 

 delicacy. The end is fine, to pick up the smallest objects, 

 the base stout, to manipulate the largest. Both mandibles, or 

 jaws, are movable, as opposed to all mammals, which move 

 only the lower jaw. Its variations in construction are ex- 

 treme but always perfectly adapted to each bird's particular 

 needs. 



The sparrows and finches with their short, heavy, sharp- 

 edged bills are able, with incredible rapidity, to shell the 

 smallest seeds. All are familiar with the formidable hook- 

 like structure of the hawk and eagle. The sandpipers, 

 woodcocks, etc., have a long and slender bill, soft and pliable, 

 scarcely more than skin stretched loosely over a long bony 

 framework. The sense of touch is highly developed in the 

 bills of these birds, enabling the woodcock, for example, to 

 instantly detect a choice morsel underneath the surface of 

 the mud when it comes in contact with the random thrust of 

 the bird's bill. 



The woodpecker has a hard, sharp pointed bill with a 

 spring-like arrangement at its base which may be to prevent 

 the "jar" giving the bird a headache. The ducks have a 

 sieve-liked arrangement similar to and operating in the 

 same way as a miner's sluice, the water washing and sep- 

 arating the mud from the food particles. So we might 

 continue, but the above examples show the specialization 

 and versatility of this organ. 



The eye of the bird is a delicate, rather complicated 

 but highly efficient organ. It far exceeds the unaided eye of 

 man in both scope and delicacy, and its ability to focus 

 rapidly and accurately is developed to a marvelous degree. 

 Observe an eagle or a hawk soaring aloft until it seems but 



