28o THE MIGRATION OF BRITISH BIRDS 



winter flights of the Snow Bunting, for instance, we never 

 observe any of their effects in the extreme west of Eng- 

 land. Birds of various species may literally swarm along 

 our eastern coasts ; all winter migrants from the Con- 

 tinent, yet the more inland districts are not affected. No 

 matter how abundantly the Hooded Crow may pour 

 into the districts of the Wash, we never see a corre- 

 sponding increase of Hooded Crows say in the neighbour- 

 hood of Sheffield, not 80 miles away, and where the 

 species is very rare. Wading birds, Ducks and Geese, 

 may oscillate between the Continent and our eastern 

 sea-board, but the movement is purely local, confined to 

 the feeding grounds of those individuals of the species 

 that frequent the districts affected. To all these local 

 misrrants the route must be familiar ; but there is not 

 the slightest trace of any attempt to increase or prolong 

 that route into other areas. Birds may seem to be 

 flying this way and that, entirely at the mercy of the 

 elements, but there can be no doubt whatever they 

 know perfectly well where they are going — they are 

 following familiar routes to other and more open haunts, 

 anticipating a storm perhaps by hours, or retreating 

 from a frost that has suddenly sealed their feeding 

 places. Spasmodic much of this winter migration may 

 be, fitful as the meteorological changes that initiate 

 it, but unquestionably in conformity with order and 

 law. 



Every observer of birds must have often remarked 

 the effects of an unusually severe winter upon them. 

 Species will then come near to houses or visit localities 

 where they are never seen under ordinary circumstances. 

 I have known Red Grouse, when the moors have long 



