WiniLs on llic Fliylit uj (iidls and utiier Birds. 425 



{Alauda arvensis) ; in 1871) Kcd-tliroatcd Divers {Colymbus 

 septentrionalis) almost by the million; in 1880 coimtless 

 numbers of the Pied Flycatclier {Muscicapa atricapilla) ; but 

 none of these hosts, so far as was observed, came to England. 

 Other writers besides Herr Gatke have insisted on the impor- 

 tance of wind in its relation to migration, while, by some 

 who have other theories, it has been curiously ignored. 

 By Mr. John Cordeaux its influence was recognized years 

 ago. Writing from the Humber-mouth in 1881, he laid 

 down as an axiom that, "with southerly or westerly 

 winds, not amounting to gales, normal migration [to the 

 east coast in autumn] is the rule, but with winds in the 

 opposite direction the results are very opposite^' ('Third 

 Report on the Migration of Birds,' p. 39). Subsequently 

 he seems to have modified his opinions a little as to 

 direction. 



Although, when I lived at Cromer, my attention, like 

 Mr. Cordeaux's, used to be directed to all kinds of birds, 

 I exercised special supervision on Gulls (Laridge), par- 

 ticularly the Herring and Lesser Black-backed Gulls [Larus 

 argentatus and L. fuscus), the most plentiful and the 

 easiest to watch. I think it will be shown that these Larida^ 

 give a key to what obtains in most other birds, for the wind 

 which suits them, — and I shall show presently that in autumn 

 it is always a contrary wind, — is most acceptable to all species 

 under similar conditions. 



To what extent the LaridoK are really birds of passage 

 over the North Sea it would be hard to say, but it has been 

 over and over again remarked that, as regularly as autumn 

 comes round, great numbers of them, chiefly of the two species 

 just named, are to be seen at Cromer passinff along the shore 

 and always flying west. INIany have been the surmises as to 

 their destination and why they should almost invariably adopt 

 the same course and go in the same direction, and several 

 times 1 have corresponded with Mr. John Cordeaux about 

 this subject. It is fortunate that on the coast of Lincolnshire 

 there should be a naturalist who for a long period of years 

 has made the migration of birds a close study. In 1884 both 



