84 HIRUNDO RUSTICA. 



When we take a broad view, and survey the world, things bear a 

 different aspect. Nay, we may see migration perhaps beyond — in the 

 Universe, in comets, stars, &c. Not, however, to soar too high, and keeping 

 to birds, my view is that they Uve in a groove, and have Httle vohtion 

 allowed them. The forces which surround them are enormous. No doubt 

 it is a " reign of law." 



In addition, it may be said that perhaps few species are never touched 

 by migration — certainly few in the British Isles. To one accustomed to 

 repose immediately under an old rookery, to whom the punctuality of the 

 morning departure and evening return is well known, to whom the midnight 

 '' caw '' of the disturbed inhabitants, mingled with the dreary sound of the 

 rustling branches, speaks (in his half-awakened state) within, of the storm 

 raging without, to whom the arrangements of the birds in their nursery bring 

 back the almost forgotten days of his own childhood — to such a one, perhaps, 

 a migrating Rook seems almost as improbable as a migrating Dodo. Yet 

 Mr. J. H. Gurney says, in ^ The Field,' Feb. 19, 1876, p. 212 :—^^ Flocks of 

 migrating Rooks annually arrive on the coasts of Norfolk from across the 

 German Ocean during the months of October and November. In the early 

 part of November 1875 I observed that these autumnal flocks were unusually 

 large and numerous, mingled with a considerable proportion of Jackdaws. 

 These flocks gradually became dispersed, and by the end of the year had 

 ceased to be sufficiently numerous to attract attention. Probably many of 

 the birds which composed them may have passed out to the southward." I 

 have seen enormous streams of Rooks migrating from the mainland to the 

 island of Mull ; but the coast of Scotland is not very far distant. 



That wind is the chief factor in migration, is, I think, confirmed by 

 Mr. E. W. H. Holdsworth, in his article '' on Ceylonese Birds " (P. Z. S. 

 1872, p. 408). /'The migration of birds within and into Ceylon takes place 

 at the changes of the monsoons. At the first indication of the N.E. monsoon 



