THE BIRDS OF HELIGOLAND 247 



the note, ' Many pilaris,' not only under the dates 20th, 24th, and 

 30th December, but also as late as on the 8th, 12th, 13th, and 28th 

 of the following January. February appears to be the only month 

 of rest for this species, and even then a sudden frost and heavy 

 snowfall may drive southward such flocks as have still lingered 

 in the north. 



The return passage begins in March; and, strange to say, flights 

 of hundreds of birds are still regularly met with in the course of 

 May, hopping about for half the day on the grass plains, and 

 continuing their journey in the evening. 



The movements of this Thrush seem to be as unrestrained in 

 respect to the time of day as they are in regard to the seasons. 

 Like other Thrushes, the birds prefer the night for their passage, 

 but they also arrive at all times of the day in flocks consisting of 

 twenty, fifty, but mostly of hundreds of individuals. 



The arrival of a migratory host of such dimensions in dull and 

 misty weather presents a curious scene. At a height of about 

 three hundred feet the birds cannot be seen under such conditions, 

 only their harsh rattling cries are audible through the dense clouds 

 of mist. All of a sudden the foremost members of the drove 

 become visible, dropping almost perpendicularly. These are followed 

 in quick succession, and in a similar manner, by the rest of the 

 flock, all alighting on the same spots as those which preceded them, 

 so that for several seconds a cascade of living birds is presented to 

 our view. 



No doubt a similar precipitation, even if only of solitary indi- 

 viduals, also takes place at night ; for on one occasion at least, one 

 of these Thrushes had the misfortune, in the dark, to impale 

 itself on the lightning conductor of the lighthouse, and that 

 with such force that the point of the rod which had penetrated 

 the breast projected several inches on the other side beyond its 

 back. 



The Fieldfare breeds in large numbers in Scandinavia, and 

 stragglers are met with as far as south Germany. Seebohm found 

 the bird on the Jenesei above 70 N. latitude, while Dybowsky has 

 met with it on Lake Baikal and in Daiiria, so that its breeding 

 range undoubtedly extends from Norway in the same latitudes 

 through Asia, at least as far as the Lena. 



