vir FLIGHT 249 
How, then, did the idea originate that the tail 
was not employed as a rudder? It was owing, I 
believe, to the fact that a bird who has lost his tail 
still manages to direct his course without great 
difficulty. A Rook whom one of the many tussles 
that go on in a rookery has left tailless is not a ship 
without a helm. He can steer, but, as far as I have 
observed, he cannot rest between the strokes of his 
wings. The tail is a valuable parachute, and, bereft 
of that, he must not loiter. His loss, too, reduces his 
power of stopping suddenly. Moreover, steering is 
not necessarily perfect steering, and I have no doubt 
that a tailless swallow misses many gnats which he 
might otherwise have caught. 
Two things are quite clear, then: (1) the tail is 
a rudder ; (2) there is some other means of steering. 
I-think I have seen gulls when flying fast adopt 
another method which is in its nature the same— 
let down a foot on the side towards which they wish 
to go. More often they kick vigorously when they 
make a sudden turn, or when they are about to settle, 
working the feet together, and not alternately as they 
do in swimming. Clearly, steering by means of the 
feet must be limited to web-footed birds. 
There is another plan very different from those we 
have mentioned. If he wishes to steer to the left, the 
bird flings himself on his left side, his left wing point- 
ing downward and his right upward. The onward 
course of the fore part of his body is retarded by his 
outspread wings, the hinder part moves more quickly, 
and this causes him to describe a curve. So far, it is 
simple enough, but when we come to inquire how the 
