THE WEIGHT OF GROUSE 143 



assimilation ; (2) by the production of toxins in the alimentary canal, 

 many of which are absorbed by the blood ; and (3) by (but this is 

 a minor matter) the worms absorbing, living on and growing on 

 food which in their absence would have served to nourish their 

 host. 



(c) Coccidiosis, especially in young birds, causes excessive emaciation 

 and frequently death. 1 



It would be interesting, were it possible to collect sufficient figures, to compare 

 local variation in the average weight of healthy males or females with 

 local differences in the height above sea-level, the rainfall, the character variations 

 of the subsoil, or the prevalence of disease. For this purpose it would 

 be reasonable to take wide natural divisions such as those which are plotted 

 out for meteorological records, in preference to artificial divisions such as county 

 boundaries and political districts. In attempting this, however, it must be 

 remembered that for a number of years it has been the practice to introduce 

 birds from one part of the country to another, perhaps a hundred miles or 

 more away. This practice makes it difficult to trace true local variations either 

 in size or in other characteristics. It is true that particular districts have 

 been credited with the production of birds distinctly above the average in size 

 and weight. Midlothian, Caithness, and the west coast of Scotland each claim 

 to produce Grouse of a high average weight. 



To establish this a much more extensive series of weights should be 

 taken than has hitherto been possible. So far as the Committee have been 

 able to ascertain, it is difficult to say with certainty that any one district 

 produces birds of a definitely larger type than any other. The result of the 

 evidence collected is given in the form of a Table on p. 144. 



1 Vide chap. xi. pp. 252 et geq. 



[TABLE. 



