THE BIRDS OF MONGOLIA ETC. 107 



« 



numerous towards the middle of that month, but are only singly distributed 

 in Kan-su, at the sources of the Tetunga. 



We found them wintering at Lake Hanka, on the open parts of 

 the river Sungatch, in small numbers ; but in spring, late in March and 

 early in April, they are very plentiful, but always in small flocks of from five 

 to twenty birds, and never mixed with other species. 



The autumnal migration from Ussuri country occurs in September and 

 October ; and in the latter month we often saw flocks of these Ducks on the 

 Japanese Sea; and in December some wintering ones came under our 

 observation at the port of St. Olga. 



276. Mergus merganser, L. Crahal holshoy. 



During the spring migration in March and April we noticed some 

 specimens at Dalai-nor, on the 14th of February atTsaidam, early in March 

 at Koko-nor, on the Buhain-gol, and in April in Kan-su, on Buguk-gol. 



On its autumnal migration this species was observed only on the river 

 Tola, near Urgey, in the first half of September. 



At Lake Hanka it arrives early in March. The principal migration, 

 however, takes place at the end of that month and early in April ; and by 

 May not a single specimen is to be seen there. When migrating they 

 usually form small flocks together with other species. 



In its habits it is very shy, and therefore difficult to shoot. 



277. Mergus serrator, L. Crahal cllinnohvostoy. 



Is scarcer even than the preceding species, having been observed by us 

 in Mongolia only on Lake Dalai-nor. 



In Kan-su, also, only one young one migrating has been obtained ; and 



Q 2 



