154 THE BIRDS OF MONGOLIA ETC. 



21. Circus spilonotus, Kaup. 



Has been found by us in great numbers on Lake Dalai-nor and in the 

 Hoang-ho valley, in marshes overgrown with reeds, where it also nests. In 

 other parts of Mongolia, where there are no marshes, the Harrier is very rarely 

 to be seen. In Kan-su it does not breed; but in the end of September we 

 noticed here several migrating specimens. Again, we met with it as wintering- 

 in the marshes of Tsaidam, as well as on the northern bend of the Yellow 

 River and in S.E. Mongolia ; in the two latter localities it keeps in the larger 

 patches of grass, especially in Lasiagrostis splendens. 



Circus spilonotiis most probably does not winter at Koko-nor, but arrives 

 there in spring, about the end of March. It is remarkable that we have 

 never seen, either in Mongolia or Ussuri country, the common or even the 

 Marsh-Harrier ; neither has it been observed on the Amur, but is occasionally 

 met with on the other side of Lake Baikal ; and according to Swinhoe it has 

 also occurred on the coast of China proper. Although female and immature 

 specimens of the two latter species are very hard to discriminate on the wing 

 from the present one, still I think that if the common Harrier occurred there 

 I should have obtained at least one specimen during my stay of three years 

 in Mongolia and two years in Ussuri country. 



22. Strigiceps cyaneus, L. Lun polevoy. 



Has been found wintering in Tsaidam and the Zahar country. At Dalai- 

 nor it was met with in rather small numbers during the spring, and has not 

 been observed in the Hoang-ho valley. 



On a small marsh at Ala-shan we found, in the beginning of June, a nest 

 constructed in some very thick reeds, as is usually the case with this bird. 

 The nest contained two partly incubated eggs, of a somewhat dirty white 

 colour: largest diameter I'''73, smallest diameter 1'''38. 



Once only we observed it in Kan-su, during the autumnal migration, in 



