54 THE GROUSE IN HEALTH AND IN DISEASE 



Grouse, including five hundred and forty adult birds of both sexes and forty 



chicks and pullets. These, however, cannot be taken all together in one 



series. It is essential, for purposes of comparison, that the male 



Method of 



studying birds in their two plumages should be taken separately in two lots, 

 and the females in a similar manner. Therefore the skins have to be 

 divided as follows : 



No. of skins. 



Male birds in winter plumage . . . . . .241 



Male birds in autumn plumage . . . . . .120 



Female birds in autumn plumage . . . . .108 



Female birds in summer plumage . . . . 71 



Immature birds of the first six months .... 40 



The largest series of skins is therefore that of the male birds in winter 

 plumage, and it so happens that this set, both as regards sex and plumage, 

 is best adapted by its general uniformity to give some result when arranged 

 map-wise over a large outline of Scotland and England. 



An analysis of the greater part of the collection of skins is given in 

 the Table on p. 55. 



Having thus arranged the skins into lots which are sufficiently uniform 

 Results of * a ^ ow f comparison, and having arranged one of these lots, the 

 com- cocks in their winter plumage, for instance, according to the localities 



parison. 



from which they were obtained, it becomes possible to make the 

 following deductions : 



(l.) That the general uniformity is very much more marked than might have 

 been expected considering the character for variability which has 

 always been attributed to the bird; the variability is lost in the 

 mass, though it is visible in individuals. 



(2.) That, allowing for a good many exceptions, there is certainly a greater 

 tendency to blackness in the birds of the northern Highlands 

 than in those of the south. Or, one may say that in passing 

 from the north of Scotland southward and westward, there is an 

 increasing tendency to the bright red and dark red types of Grouse, 

 which culminate in the very characteristically bright red bird of Wales 

 and of the Midlands of England, in which the predominating colour 

 of the feathers of the breast and under parts generally is red with 



