358 THE STRUCTURE AND LIFE OF BIRDS cuHapP. 
the ocean till they reach the West Indies. Even 
then, it is said, they will sometimes pass the first 
islands they reach and press on to more distant ones. 
From Nova Scotia to Hayti, the nearest West 
India Island available, is over 1,700 miles. Either, 
then, they fly at an almost incredible pace, or else 
they remain upon the wing an almost incredible time. 
But though it is easy to say that such a feat is 
incredible, it is very difficult to get over the evidence. 
One witness after another declares that he has seen 
flocks of them flying southward, several hundreds of 
miles to the east of the Bermudas, on which islands 
they alight only if the weather is unfavourable! 
The Beam-wind Theory. 
Several very good observers, among them Herr 
Gatke himself, are of opinion that migratory birds 
dislike flying with a tail wind, ze. with the wind 
directly behind them, and that what they prefer is 
a beam wind, ze. a wind striking them upon the 
shoulder. A comical explanation of this supposed 
fact used to be given—that a wind from behind 
ruffled up the bird’s feathers. But as he is moving 
with the wind, and necessarily at a greater pace, since 
in addition to that of the wind he has the velocity 
due to his own efforts, this explanation will not hold. 
Besides this, keepers of Homer Pigeons seem all to 
agree that their birds make much better times when 
1 See The Naturalist in Bermuda, by H.M. Jones, p. 72; and 
North American Birds, by Baird, Brewer, and Ridgway, vol. i. 
p- 140, 
