46 



the fact that the Northern Bluethroat migrates at any rate in 

 spring in a very narrow column or columns, and bearing but 

 little relation to the extent of the winter quarters and breeding 

 range ? Shall we not also be much safer in assuming that the 

 large numbers occasionally noted on the island late in May are 

 individuals breeding in the far north ? We should expect those 

 whose nesting homes lie in the most southerly portions of the 

 breeding range to have already commenced operations by May 

 26th. Even in the Petchora valley, Messrs. Seebohm and Harvie 

 Brown note that the Bluethroat arrived in this northern locality 

 quite a week earlier. Again, the winter quarters of the Blue- 

 throat in north-eastern Africa are very much more confined in lati- 

 tudinal extent than are the breeding grounds in northern Europe, 

 so that there must be considerable spreading of the flocks, and, 

 consequently, no rigidly adhered to, south-to-north direction of 

 flight during the spring migration, if conducted either in many 

 narrow, or in one broad column. To the writer there seems to 

 be little doubt that the Bluethroats calling at Heligoland during 

 May form a succession of flocks travelling in a narrow flight over 

 a customary route to breeding grounds in the north of Scandinavia 

 and Lapland, and that their non-appearance in certain years is 

 due to a deflection of the stream which may readily miss so tiny 

 an area as the island, or even break the journey at other points. 

 The fact of individuals so rarely occurring in intermediate 

 localities, though surprising in itself, is much less difficult of 

 comprehension on this theory. Herr Gatke himself perhaps 

 gives a clue to this mystery in his charming opening words, 

 referring to the progress of migrants, where he speaks of our 

 " sharing in their joy when some high mountain valley offers a 



portion some temporary rest and refreshment " (p. 3). 



But the paucity of observers in southern Europe must by no 

 means be overlooked in accounting for the absence of spring 

 visits of this species. 



As before noted, Herr Gatke does not devote much space to 

 the consideration of the autumnal flight of migrants which pass 

 from north to south. In addition to the Bluethroat, however, he 

 refers to a few other birds. Amongst the latter is the Eed- 

 throated Pipit, a species breeding abundantly above the Arctic 



