268 FIELD ZOOLOGY. 



best to appear well before some maiden blackbird. In 

 some species of birds, the tail is more expressive of the 

 emotions of the bird than is any other organ of the bird. 

 The stiff feathers of the tail are called rectrices. 



In birds, as in all classes of animals, there are facts 

 expressing gradations of development. We speak of the 

 birds of highest nervous development as the highest 

 family of birds. Nor is this fact without its accompanying 

 facts of classification. These are also the birds in which 

 we find the altruistic instincts best developed, in which we 

 find fatherhood no longer deprived of its share in the 

 interests of the offspring. Again, in the highest class of 

 birds, we touch most closely the life of the human family, 

 where, oftentimes, the bird is willing, if we will let it, 

 to work in happy partnership with man, both reaping 

 legitimate gain from the same region. In this class of 

 birds, we find some that are able to pit their shrewdness 

 against the shrewdness of man, and in eight times out of 

 ten come out ahead; for example, the English sparrow. 



The Wing. 



The wing is the organ of flight par excellence. It 

 has furnished to the human race the inspiration to "go 

 and do likewise" from the days of Darius Green to the 

 Wrights and the host of other present-day aviators. 

 The albatross and the gulls are almost tireless on the wing. 

 It is true for the bird in general that it seems to be in more 

 stable equilibrium when off its feet, either in the air or the 

 water, than while it is perching or walking, probably due 

 to the fact that the base within which the center of 

 equilibrium then lies is so broad, the wings being set 

 quite a good deal forward of the feet. The quadrupeds 

 below birds go on all fours, with the head little raised above 



