38 THE BIRDS OF HELIGOLAND 



to direct its migration-flight in an equally unswerving southerly 

 line. The breeding homes of this bird range through the higher 

 latitudes of northern Asia and European Kussia to Finmark, while 

 in winter it migrates as far south as the Sunda Islands. Collett 

 met with this species during the summer months at the Porsanger 

 Fjord beyond 70 N. latitude; such individuals could therefore 

 migrate from this locality only in a line direct south, inasmuch as 

 the bird has only once been shot in Heligoland in October 1854 

 and has never been observed in Germany. To these Warblers may 

 be added the case of the Northern Nightingale (Sylvia philomela), 

 The most western nesting stations of this bird are found in 

 south Sweden and Denmark, and if it showed the least inclina- 

 tion towards a westward deviation from its southerly autumn 

 course, it would not fail to touch Heligoland, if only in small 

 numbers, every autumn. Quite to the contrary, however, only 

 one instance of its occurrence on the island has ever been recorded, 

 and even that is really of no value to the subject under discussion, 

 inasmuch as the bird in question was caught at the lantern of the 

 lighthouse on the night from the 4th to the 5th of May 1855. 



The area next to be discussed comprises Finland and the more 

 northern parts of European Russia. Here we find the most 

 western nesting stations of the Siberian Chiffchaff (Sylvia tristis), 

 the Yellow-headed Wagtail (Motacilla citreola), the Yellow- 

 breasted Bunting (Emberiza aureola), the Terek Sandpiper (Limosa 

 einerea), and the Red-footed Falcon, the last-named species being 

 met with numerously even as far north as Archangel. The rare 

 appearance of these species in Heligoland, or their total absence 

 from the island, proves that their autumn migration must be strictly 

 confined to a southerly course, since any deviation from such a 

 line of flight to the west could not fail to convey them to Heligo- 

 land in large numbers, as is the case with other species whose 

 breeding homes lie in the same districts. The Siberian Chiffchaff 

 has only once been caught in Heligoland, though it has been seen 

 on two subsequent occasions. Of the Yellow-headed Wagtail I 

 have only taken five young birds in autumn plumage within the 

 last fifty years, and of the Yellow-breasted Bunting during the same 

 period, two young birds in autumn plumage and a female in the 

 spring. The Terek Sandpiper has never been seen in Heligoland ; 

 in Germany and northern France it appears to have been shot 

 only once; while it has been met with in no other districts 

 lying to the west of its breeding stations. The Red-footed 

 Falcon has been shot five times in Heligoland, but invariably 

 in the summer, and under conditions which would lead one to 

 assume that the birds in question would have to be counted among 



