DIRECTION OF THE MIGRATION FLIGHT 25 



Heligoland than that of any other of its ninneroiis visitors. A 

 mere surface glance at the map shows, in the most striking manner, 

 how manj' large rivers, in addition to the Ural chain, this bird 

 has to cross, almost at right angles, in the course of its journey 

 from Datiria to Heligoland every autumn. 



Direct observations in Heligoland, either from watching the 

 flight of passing migrants by day, or noting their call-notes during 

 the night hours, have established the following main results in 

 regard to the direction of the migration flight, viz., that in autumn 

 the migration proceeds from east to west, and in spring in the 

 opposite direction. Further, that in the cases of all the species and 

 individuals noted on the island, these courses are rigidly maintained 

 during the passage, and such rare deviations as do occur never 

 extend bej'ond one or two points of the compass. 



Not all birds, however, reach their winter destinations by an 

 autumn j^^^ssage proceeding in this simple westward direction. 

 Many, on the other hand, are sooner or later obliged to turn south- 

 wards, in order to reach the lower latitudes in which their winter 

 quarters are situated ; in the case of some species the original 

 westerly direction of flight is maintained throughout the whole of 

 the immense stretch of road from the eastern countries bordering 

 the Amoor river to the west of Spain, and it is not until they reach 

 the latter district that such birds turn to the south for the purpose 

 of crossing the Mediterranean near Gibraltar ; others, whose breeding 

 homes lie further north, turn to the south in England, either to 

 pass across the Channel into France, or to reach Spain via the Bay 

 of Biscay; while still others, originating from the far north of 

 European or Asiatic Russia, turn southwards even still farther north 

 m Upper Scandinavia. It might perhaps be supposed that it was 

 the sight of the sea which induced birds thus to alter the direction of 

 their migration flight, were it not that the hosts of wanderers change 

 their course long even before reaching the sea ; the Hooded Crow, for 

 instance, does not get to the western parts of England, but turns to 

 the south as soon as it reaches the central portions of that country. 



Besides Buzzards, Starlings, Larks, Swifts, Plovers, Curlews, 

 and Geese, the numberless bands of Hooded Crows which for 

 the most part fly during migration at a very low elevation, most 

 clearly demonstrate the western direction of the autumnal migration. 

 The breeding area of this species extends eastwards as far as 

 Kamtschatka. According to observations of Eugen von Homej'er, 

 carried on for a large number of years, the flights of these migrants 

 arriving in Poiiierania come from the east and travel onwards in 

 a westerly direction. Such of the wanderers as pass the night in 

 Holstein arrive in Heligoland about eight in the morning. From 



