LOCAL VARIATION IN PLUMAGE OF GROUSE 63 



autumn - winter plumage exactly as do the feathers of the lower breast and 

 abdomen. 



This persistence of winter-plumage feathers on the chin, lower breast, and 

 abdomen is common to both cock and hen ; but in the cock they remain, as 

 a rule, until replaced by the following winter plumage, persisting throughout 

 the autumn plumage change ; whereas in the hen they are persistent only 

 to June or July, and are entirely replaced during the autumn change. 

 Even when the autumn plumage is put on, the yellow feathers of the 

 preceding breeding plumage are almost always to some extent persistent, and 

 they are to be found in the chin of the hen bird even though the throat and 

 neck may be unusually red and therefore unusually like those of a cock bird. 



From January to May there is no possibility, as a rule, of confusing the 

 sexes. In June and July confusion is unlikely, but in August and onwards 

 to December the differentiation of the sexes by the plumage is sometimes a 

 difficult thing, and the best guide is the persistence of feathers of the preced- 

 ing plumage such as occurs upon the chin in particular. We must recollect 

 that the dominating plumage of the male is the winter plumage, while that 

 of the female is the summer or breeding plumage. 



In the autumn, especially from September and October onwards, there is 

 the additional difficulty of distinguishing old birds and young. 



. * ^ . . Distinction 



" Young birds in July resemble the adult female in breedins: between 



'"' old and 



plumage in their general colour, but the flank feathers of the adult young 

 plumage begin to appear about this time. By the month of November 

 the young are generally not to be distinguished from the adults." This quota- 

 tion is from Mr Ogilvie-Grant. 



There is one sign of age in the majority of birds in the shooting season, if 

 it has not become obliterated — namely, the mark across the claws of recent 

 shedding. Very often one may find the nails or claws still adhering Qroove 

 to the toes, though ready to drop off, so that a gentle application of on claw, 

 force removes them like small caps, leaving the new shorter claws beneath, each 

 marked b}^ a groove where the old claw was attached. This groove persists 

 often for some little time, and is an infallible sign that the bird is over a year 

 old at least. Young birds of the year do not shed their claws, and therefore 

 never have this groove. 



There is another method of determining a bird's age which is often used as 

 a rough indication upon the moor, namely, to pull out the third primary 



