i897-] Pai^mkr. — The Migration of Birds. 17 



August, though perhaps all are not necessarily passing beyond 

 the British area. Both these classes of emigrants probably 

 are increased in numbers by birds of the same species which 

 pass the summer further north than the British Isles, and 

 which, having reached our shores as immigrants, are also 

 moving southwards along our coast line. 



September witnesses the height and the close of the emi- 

 gration of the bulk of the smaller British summer visitors. 

 Over forty of these are recorded as moving off in this month, 

 and about the same number of partial migrants. There are 

 often tremendous rushes of migratory birds towards milder 

 climates in this month, due to outbursts of ungenial weather. 

 The partial migrants are much on the move in October. 

 Emigratory birds are observed passing southwards, and feeding 

 as they go, during the daytime ; but their oversea flights 

 are usually undertaken at night. 



After the middle of November, and through the winter 

 during cold spells, movements of a different nature take 

 place, due to severe weather. Birds specially affected then go 

 either to warmer districts within the British Isles, or to more 

 southern regions. When frost sets in, particularl}^ if there is 

 snow^ and sleet, it causes an immediate rush to the coast, and 

 especially to the western coast of Ireland, where amilder climate 

 almost always prevails, even when there is very cold weather 

 in other parts of the British Isles. If the cold is severe and 

 prolonged, the isles off the south-west coast of England and 

 Ireland are sought. Occasionally, as in December, 1882, these 

 usually safe retreats failed the refugees ; the hard}^ Snow 

 Bunting perishing with the rest. The species which appear 

 especially susceptible to cold, either constitutionally or from 

 deprivation of food (most probably the latter), are the Missel 

 Thrush, Song Thrush, Redwing, Fieldfare, Blackbird, Green- 

 finch, Linnet, Starling, Eark, Water Rail, Eapwing, Curlew* 

 Snipe, and Woodcock. Cold weather migration is performed 

 in both the day and night time, the more extended flights 

 appearing to be taken in the night. 



The earliest spring migrants are recorded in February, 

 when such partial migrants as the Pied Wagtail and Eapwing 

 return to the Orkneys and other northern stations, and 

 certain rock-breeding seabirds revisit their nesting haunts. 



