THE ORNITHOLOGIST. 



Vol. I. APRIL, 1896. No. 2. 



ON THE EFFECT OF WESTEELY WINDS ON THE 

 FLIGHT OF GULLS (LABIDM) AND OTHEK 

 BIRDS.* 



By J. H. Gueney, F.L.S. 



In all birds it appears that wind, or trie force of wind, is 

 the prime mover in flight — that is to say, the action of the 

 wings is greatly regulated by the direction and velocity of 

 the wind, though, joined to this, the actual motive power is 

 gravitation to the earth's surface. If there is absolutely no 

 wind a bird cannot fly its fastest ; its flight is, on the contrary, 

 often somewhat listless, and locomotion probably becomes 

 laborious. It follows that it is easier for a bird to make head- 

 way where there is some slight opposition — to fly against a 

 gentle wind rather than with it. The truth of this hypothesis 

 has not been recognised by many writers, but it may be 

 especially tested on the coast of Norfolk. This juts out into 

 the North Sea like a great rounded peninsula, and just in the 

 middle of the bend lies the little town of Cromer, where, or in 

 its neighbourhood, most of the following observations have 

 been made. From its position Cromer is peculiarly adapted 

 for watching the direction and effect of wind and all the 

 autumnal migratory movements of the lower-flying birds, so 



* Reprinted, with author's revisions, from " The Ibis," for October, 1895. 



