36 BOMBAY DUCKS 



birds. Most of the fowls of the air are able to boast 

 of a caudal appendage of sorts. Some possess resplen- 

 dent tails the products, we are told, of sexual selection, 

 the admiration of the ladies for that which is beautiful. 

 In very many cases the tail acts as a rudder or steering 

 apparatus to its possessor during flight. 



This is well seen in the king-crow, the swift, the swal- 

 low, and, indeed, in most fly-catching species. The tail 

 feathers of the woodpecker are very stiff and are of 

 great use in helping the bird to maintain its position 

 on the trunks of trees. In nearly every case the tail 

 is of use during the flight of its possessor. Nine birds 

 out of ten spread out their caudal feathers when they 

 take to their wings. The feathers of a bird's tail are 

 arranged so that the tail is almost impervious to air. 

 They are, moreover, provided with powerful muscles, 

 so that when the bird flies they can be spread out in the 

 shape of a fan with a curved surface, the concavity being 

 underneath. This is especially well seen in the flight 

 of a dove or a kite. Nevertheless, the tail is not indis- 

 pensable to a flying bird. 



I once cut off, quite close to their bases, the tail feathers 

 of a pigeon ; the bird flew quite easily after the opera- 

 tion. The motion of the wings was perhaps rather more 

 rapid, and the flight generally more laboured ; nor did 

 the bird steer itself so well as usual. Therefore, the tail, 

 although both an ornamental and useful organ, is by no 

 means indispensable to a bird. As has before been 

 remarked, the caudal appendage is one of the few 

 luxuries which Nature allows her children. 



In the case of some animals, the use of the tail is not 



