LIFE AT HIGH ALTITUDES HINGSTON 343 



tain is absolutely barren, yet the animals manage to pick up some 

 food. When snow is on the ground they dig through it to the vege- 

 tation. The Tibetans said that they scraped up roots. I have seen 

 them eating the fresh dung of a pony which had been well fed on 

 grass and grain. In April, when the grass is just commencing to 

 appear, the sheep struggle hard to obtain food. With their fore feet 

 they dig into the soil and shuffle aside the superficial sand in order 

 to get at the buried blades. When food is scarce, the ponies do like- 

 wise. I have seen them cutting up the ground w^ith their hoofs in 

 order to expose the hidden roots. Also they w^ade into icy lakes, 

 wdiere they feed on the water weed that grows up from beneath. 

 The mules and donkeys will sometimes eat quantities of yak dung, 

 which does not seem to do them any special harm. The pikas show 

 an excellent example of husbandry. They store up quantities of 

 seeds in their burrows to serve as a winter supply of food. 



The bills of certain birds seem specially suited for penetrating 

 frozen soil. This is of importance for the insectivorous species, 

 since in Avinter, when the ground is hard, all insects are hibernating 

 underneath stones or in the superficial layer of the earth. Compare 

 the bill of the chough, an inhabitant of high altitudes, with that of 

 its allies, the rook and crow. The chough's bill is proportionately 

 longer and sharper and better fitted to penetrate the frozen soil. It 

 is also used as a kind of lever with which the bird upturns the lumps 

 of dung in order to reach the good things underneath. The ground 

 chough is a delightful Tibetan bird of a sandy color that harmonizes 

 with the soil. It is about the size of a lark, but is supplied wdth a 

 long and poAverful bill, slightly curved like that of a chough. Now 

 this bill fulfils an important purpose. The bird is an insect feeder, 

 and must find great difficulty in securing food during the cold 

 months of the year. All insects are then in a state of hibernation. 

 But the ground chough can dig them from their places of retirement. 

 We may often see the bird boring in the soil, driving its stout bill 

 into the hard plateau until it finds the insects hidden underneath. 

 Unless it had this special instrument of excavation it could scarcely 

 exist through the winter months. 



The larks supply another example. In India there are two kinds 

 of Calandra larks : One the Eastern Calandra lark, which lives on 

 the plains; the other the long-billed Calandra lark, which occupies 

 the plateau of Tibet. They are powerful birds of heavy build, and 

 utter a loud call note when in flight. Compare the bills of these 

 two species. That of the plain bird is comparatively small, about 

 four-fifths inch in length. That of the Tibetan bird is distinctly 

 longer, its length being ll^ inches. The longer bill of the Tibetan 



