r 



98 THE GROUSE IN HEALTH AND IN DISEASE 



daily loss of small grits is considerable, and that this loss is replaced by an 

 equally regular supply picked up day by day upon the sides of moor roads, 

 or in " scrapes," or along the channel of a burn. 



But, in the event of a heavy snowfall it appears very probable that the 

 Control Grouse soon recognise that the loss is exceeding the amount which 

 tirmTof 11 can be ma de good day by day, and that in such a case they can, 

 in some unexplained way, place a check upon further loss. It 

 cannot for a moment be imagined that the bird has any sort of voluntary control 

 over the passage of grits from the gizzard. But it is quite conceivable that 

 the gizzard itself will allow a certain careless loss of any surplus number, 

 especially of the smaller pieces, so long as there is still a sufficiency of larger 

 grits in the gizzard. 



When the supply, however, is straitened, and the bird fails to find more 

 grits to swallow, it may be that less food is eaten as well, and thus the loss 

 of grits is automatically reduced. This is probably the explanation which 

 comes nearest to the truth, and it is a significant fact that a bird not only 

 loses weight, but may actually die when only half of its normal supply of 

 gizzard grits has been lost, and when the dejecta show that this amount of 

 grit is still capable of grinding up the food given to it. 



Under normal conditions the character of the grit required differs 

 with the nature of the food that is being eaten. With hard grain or seed, 

 or with berries containing seeds, it is badly needed, and must be obtained if 

 the food is to be digested. Oats and oat husks are all efficiently dealt with 

 by the quartz grit normally found in a Grouse's gizzard, but large hard seeds 

 are not, and are passed undigested. These seeds, however, are sufficient in 

 themselves to pulp fruits so long as fruits only are being eaten. But as soon 

 as heather or other fibrous vegetable matter is eaten, quartz or other stone 

 grit becomes essential. 



The possibility has been suggested that the replacement of quartz grits by 



hard seeds of fruit, and the passage of the former through the intestine may 



act as a vermifuge. So often has a diet of berries apparently 



Berry seeds n < TT i i i i i 



as a vermi- arrested a case of Helmmthiasis that it is a question to be seriously 

 considered whether enough attention is given to the encouragement 

 of berry-bearing plants upon a moor. In many cases the sheep keep them 

 so closely cropped that except where there are woods or enclosures it is 

 difficult to find a visible trace of them. It would perhaps repay the trouble 



