94 THE GROUSE IN HEALTH AND IN DISEASE 



of the crop are always found to be dry. This may be sufficient to prove 

 that the bird does not drink when the crop is full, but does not dispose of 

 the possibility of its drinking during the long periods of the day when the 

 crop is empty. Then, again, cases are quoted of moors which carry a large and 

 flourishing stock of Grouse where the ground is by no means well watered. On 

 one of the best stocked Grouse moors in Britain, the only water comes from 

 about a dozen springs and one deep burn which runs through the middle of 

 the ground. Grouse are seldom observed to resort to the burn, and it is 

 difficult to see how several thousand birds can all water at the springs. While it 

 cannot be said that this entirely disposes of the water drinking theory, it seems 

 to justify the view that Grouse are not dependent upon a large water supply. 



How far dew forms a substitute for water is a matter which the Committee 

 consider of great importance, and one to which they have given considerable 

 attention without arriving at any results sufficiently definite to be worth 

 reporting. There is a curious lack of information available regarding the fall 

 of dew, the districts in which dew is most prevalent, etc. There is probably 

 a close connection between dew and the infection of Grouse by the nematode 

 worm Trichostrongylus pergracilis. In view of the fact that the larvae of 

 this worm can only climb the heather shoots, or indeed exist on them, when 

 they are slightly damp, the Committee believe that this is one of the questions 

 which might be further investigated with advantage. 1 



PART IV. GRIT 

 By Dr H. Hammond Smith and R. H. Rastall 



The health of Grouse and of other game-birds is greatly dependent on 

 the nature of the grit they take to assist in the assimilation of their food. 

 Necessity During the autumn of 1906 the Committee made a collection of the 

 of grit, grits from the gizzards of Grouse and other game-birds. This 

 collection formed the subject of a paper read by Dr Hammond Smith at 

 Collection a meeting of the Zoological Society in May 1907. These grits were 

 Com 6 by obtained from the gizzards of Ptarmigan from Ben Mohr in Sutherland- 

 mittee. shire ; Grouse from Ross-shire, Inverness-shire, Aberdeenshire, and 



1 Vide chap. x. pp. 228, 233. 



