THE BIRDS OF HELIGOLAND 241 



comprehensive information as to the meteorological conditions at 

 the time of observation. For, as has been already fully discussed 

 in the section on ' Atmospheric Conditions which influence Migra- 

 tion/ the appearance of particular birds in greater or less numbers 

 in particular places and at particular times is most intimately con- 

 nected with the local atmospheric conditions which prevail at the 

 time being. 



This bird is caught here only in small numbers ; it frequents 

 principally open fields and grass-plots, and hence approaches the 

 throstle-bush only in rare and exceptional cases. 



Its autumn migration commences later than that of the Song 

 Thrush, the first individuals rarely arriving before the middle of 

 October. Its movements, too, are less influenced by the weather 

 than those of the last-named species. The migration lasts through- 

 out the whole of November ; smaller companies may also be met 

 with as late as December e.g. in 1886, on the 20th, 21st, and 22nd 

 of that month. 



The Redwing breeds from the centre to the extreme north of 

 Scandinavia, and within the same parallels of latitude as far as 

 eastern Siberia. Towards the east, however, its numbers undergo 

 considerable diminution. 



68. Dark Thrush [BLASSE DKOSSEL]. 

 TURDUS FALLENS, Pall. 1 



Turdus Pollens. Naumann, xiii. 289. 



Dusky Thrush. Dresser, ii. 71. 



Merle blafard. Temminck, Manuel, iii. 97, iv. 605. 



I am noting this species mainly on the authority of Claus 

 Aeuckens, he having, on the 3rd of June 1881, seen an example of 

 it at a distance of from eight to ten paces. He had time enough 

 to observe the bird to his entire satisfaction ; but, unfortunately, 

 not having a gun with him he was not able to secure it. Aeuckens, 

 who, as a careful and reliable observer probably stands second 

 to none on this island, described the bird so accurately that 

 not the least doubt remained as to its species. He was further 

 convinced of his conclusions on my showing him the skin of one 

 of these birds. The bird, moreover, has been met with pretty 

 often on the continent, and, a few years ago, was caught as near as 

 Holstein, so that its appearance in Heligoland need not be a matter 

 of great surprise. 



1 Turdus obscurus, Gmelin. 

 Q 



