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 
