214 STUDIES IN BIRD-MIGRATION 



become inextricably mixed with those of the birds of 

 passage from Northern Europe. 



During these months, especially in September, the 

 Thrush departs in company with various species which 

 have spent the summer in our islands, and its emigra- 

 tions are recorded from all sections of the British coast 

 and from the east and south coasts of Ireland, always 

 during the hours of darkness. The Thrush is, however, 

 emigratory to a lesser degree in the Sister Isle, owing 

 to its havinor a milder climate than that of Great Britain. 



Late in the year, the emigratory movements, which 

 doubtless include many of the recently arrived winter 

 visitors from Northern, and perhaps Central Europe, are 

 dependent on and synchronous with more or less severe 

 weather conditions, and these will be duly treated of 

 under Winter Movements. 



Autumn Immigration and Passage. — There is no 

 evidence whatever of the arrival of the Thrush upon our 

 shores as winter visitor and bird of passage from North- 

 Western Europe until the third or fourth week of 

 September, when it appears with great regularity, in 

 company with the early Redwings, Bramblings, Siskins, 

 Redbreasts, Goldcrests, and sometimes Woodcock, Jack 

 Snipe, and Short-eared Owls.^ 



The immigrations continue during October and to 

 the end of the third week of November, or a few days 

 beyond. During this period there are "rushes" of a more 

 or less pronounced nature to our shores, when for several 

 successive nights Thrushes pour in upon our northern 

 and eastern sea-boards in vast numbers. 



' Prof. Collett, Oversigt af Chrisiiania Omegns ornifhoJogiske Fauna, 

 p. 27, says that the Thrush departs from the Christiania district during 

 September, and continues to do so until the first days of November. 



