256 SIBERIA IN EUROPE. CHAP. xx. 



Heligolanders with whom I conversed agreed in corrobo- 

 rating, may to a large extent account for the fact that the 

 rare stragglers recorded as visiting Heligoland and other 

 countries are for the most part birds of the year on 

 their first autumn migration. It is not to be wondered 

 at that on their first journey they should frequently stray 

 from the direct course. Probably the mortality amongst 

 birds of the year is very great, especially amongst those 

 who take the wrong road on their first migration. The 

 yellow- browed warbler (Phylloscopus superciliosus, Gmel.) 

 breeds in immense numbers on the Arctic Circle in Siberia. 

 The main line of migration of this as well as of several 

 other species of birds breeding in the same district is east- 

 wards, passing through North China and conducting them 

 to South China, Burmah, and the eastern portion of India, 

 where they winter in abundance. Several birds, some nearly 

 allied, and one congeneric, migrate west instead of east 

 from the same breeding-grounds, and with these a few yellow- 

 browed warblers appear annually to mix and find their way 

 to Europe, passing Heligoland in small numbers nearly every 

 autumn. Probably most of these wanderers perish during 

 the winter, as they have been observed in spring on Heli- 

 goland only once every few years. This charming little 

 bird has once been recorded from the British Islands. I 

 saw one or two during my short stay on Heligoland, and 

 was fortunate enough to shoot one. For nearly a week, 

 whilst I was visiting this interesting locality, the weather 

 was unfavourable. There were scarcely half-a-dozen birds 

 on the island. I used to take a constitutional with my gun 



