302 THE BIRDS OF MONGOLIA ETC. 



females were sitting on eggs, and the males could only be seen singly. The 

 young, which are easily distinguished from the old birds by their white 

 underparts, leave the nest at the end of July or beginning of August ; at 

 least, from that time onwards we often met with them. Its range does not 

 extend further north than Kan-su. 



115. Hydrobata sordida, Gould. Oliapha griasnaya. 



We observed H. sordida in winter in Northern Tibet, about the Burhan- 

 Bulda mountains. They kept company with the preceding species at the 

 unfrozen places of the river Nomohun-gol and its tributaries. I myself did 

 not see it at Kan-su; but my companion observed a pair at the river 

 Tetung-gol. 



116. Pterorhinus davidi, Swinh. 



Pterorhirms davidi, Gould^ Birds of Asia^ part xxiii. pL 

 Hey-la-po, Chinese. 



This species, lately discovered by Pere David, was obtained by us in 

 S.E. Mongolia, Ordos, Ala-shan, and Kan-su. It inhabits the thick bushes 

 growing on the mountains, and does not avoid plains, and is tolerably 

 common in the tamarisk-groves of the Hoang-ho valley. In richly wooded 

 localities (like Muni-ul, Ala-shan, and Kan-su) it is sometimes found on high 

 trees, but always prefers the low bushes. It is a very lively and restless 

 bird, always moving about in the bushes, and flying only now and then short 

 distances and from one bush to another. Its flight is similar to that of 

 Rhopophilus pekinensis : the bird moves with a continuous jerky motion, the 

 long tail partially erected. It runs very fast, and often goes from one bush 

 to another without leaving the ground. Its song is really charming, being 

 a loud clear whistle, and can be heard throughout the day, but usually 

 chiefly in the morning and evening. The nest is very carelessly constructed 



