2 A HISTORY OF BIRDS 



By the accident of birth, so to speak, the career of the bird 

 was determined by the shape of its fore-h'mbs. Though in 

 course of time circumstances deprived these of all importance 

 in certain species, so that they eventually became reduced to 

 mere vestiges, as in many living birds, or even suppressed en- 

 tirely as in the extinct Moas, the mammals, on the other hand, 

 have in no case suffered a similar loss ; but the hind-limbs, by 

 way of contrast, have in not a few cases similarly vanished. 



In birds the fore-limb has in all cases served as an organ of 

 flight ; even where this member has been reduced to the merest 

 vestige, it is clear that the modelling thereof is that of a wing. 

 In the mammal, on the other hand, the fore-limb presents the 

 most varied forms. Similarly, in the case of the hind-limb, 

 that of the bird presents a wonderful uniformity of structure, 

 being always used for the carriage of the body when on terra- 

 firma, but this is far from true of the mammal. 



Notwithstanding the unquestionable uniformity of structure 

 which birds present, this is apparent only when the fundamental 

 structure is considered in relation to that of other groups. To 

 the ornithologist birds display a marvellous range of variation, 

 and in so far as coloration is concerned this is undoubtedly 

 true. From the aesthetic point of view birds hold an unique 

 position, and fill a place in the world that adds more than is 

 generally realised to its charm and habitability. They seem 

 to display a joyousness in existence, an intensity of emotion, 

 that is infectious ; though, it is needless to remark, this mani- 

 festation is not a universal characteristic of the group. 



The factor which, more than any other, has secured for 

 birds the high place which they hold in the affections of men, 

 is unquestionably that of flight. Thereby they ever keep 

 themselves, as it were, before the public, and give life and beauty 

 to the world around them. And this is true more especially of 

 such species as seek their daily bread in the open, on the wing, 

 or indulge in aerial evolutions apparently out of the sheer ex- 

 uberance of spirit. There must be few who have not gazed 

 with admiration at the hovering feats of the Kestrel, and still 

 fewer who have not felt moved at the wild, screaming flights of 

 a flock of Swifts at dusk, while the marvellous spiral evolutions 

 of the Skylark, accompanied by outpourings of song, have in- 

 spired some of the finest poets who have ever lived. 



