SIDE I.IGHTS ON BIRDS 



This table affords the means of making some 

 remarkable comparisons. Thus the pheasant 

 and the great black-backed gull have approxi- 

 mately the same weight to carry, yet the latter 

 has a wing-spread more than double that of 

 the former. The guillemot, singular also in the 

 respect that it lays the largest egg in relation to 

 its size, has lib. 12^ ozs. to bear on a wing-spread 

 of 25 i inches, whereas the tern has only 4 oz. 

 to sustain on an expanse of 31 inches. 



It might be imagined that the birds with the 

 widest wing area in proportion to their weight 

 were those of the swiftest flight, but this is by no 

 means the case. Both the guillemots and the 

 pheasants, by reason of their powerful pectoral 

 muscles, and their rapid wing beats, contrive 

 to reach a speed greater than that of the gulls 

 and terns, but, on the other hand, there is no 

 doubt that the wider wing-spread combined 

 with lightness of body, gives the bird an in- 

 finitely greater mastery of the air, and that all 

 the species noted for their graceful evolutions 

 possess these features in a marked degree. 



Beaks. 

 " Practice makes perfect" is a motto which 

 applies not only to the worker but to the organs 

 of his body, the tools with which he works. 

 Organs that are put habitually to the same use 

 tend to change, slowly, imperceptibly, until they 

 become more and more in harmony with the work 

 they have to do. The bird's bill illustrates the 

 principle perfectly, and by merely looking at the 

 bill alone we are able to form some clear con- 

 jecture as to the life, habits, and environment 

 of the bird to which it belongs. 



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