12 THE GROUSE IN HEALTH AND IN DISEASE 



in heather. When placed in the open probably the eggs are 

 liable to suffer just as Plover's eggs did in 1908, and an extra 

 hard frost will sometimes split them. Even very scanty 

 heather-growth retains the warmer air, and so shelters the nest 

 and eggs from frost and winds. Moreover, if sitting has not 

 begun the eggs are generally more or less buried in the material 

 of the nest, so that they are to a great extent protected. 



The effect of frost upon the eggs of Grouse has been fully 

 discussed in the Committee's Report, and an analysis is given 

 of the Reports of nearly 200 observers in different parts of the 

 country. 1 The deductions to be drawn from this analysis, 

 though negative, are nevertheless of considerable interest. 

 They may be summarised as follows : 



1. Frost in the breeding season does not cause universal 



destruction to eggs. 



2. In some cases it seems to do little or no harm, even though 



severe. 



3. In other cases it seems to do more harm even though 



relatively less severe. 



4. The effects of a hard frost in the breeding season are apt 



to be exaggerated especially if from any other less 

 obvious cause there happens to be a shortage of young 

 birds in the shooting season. 



How it happens that eggs in one district seem to be better 

 able to withstand frost than those in other districts must remain 

 a subject for conjecture. Acclimatisation appears a more 

 probable solution than any other, for it is clearly brought out 

 by the Reports that in the more rigorous climates of the north 

 and east the eggs were less effected by frost than in the milder 

 climate of the west. Possibly it may be that in the colder 

 districts instinct teaches the parent birds to take greater pre- 

 cautions, e.g., to nest under the shelter of long heather rather 

 than in open situations. Many cases are recorded of Grouse 

 protecting their eggs from frost by covering them with loose 

 twigs of heather. 



1 Vide "The Grouse in Health and in Disease," First Edition, vol. ii., pp. 132-136. 



