268 ALLEN'S NATURALIST'S LIBRARY. 



parts to which form an individual belongs. In the average 

 female in full breeding dress the upper-parts may be described 

 as black, each feather being rather widely margined, barred, 

 and marked with orange-buff (pi. iii. fig. i). The protection 

 afforded by this plumage is so perfect that, when the bird is 

 sitting on its nest among heather and dead grass, it may easily 

 remain unobserved, though only a few yards distant. 



"This plumage, however, varies much in different individuals, 

 birds from the west of Scotland, Yorkshire, and Ireland having 

 the orange-brown bars much brighter and wider than in the 

 more finely mottled and darker specimens generally charac- 

 teristic of the east of Scotland. 



" B. Feathers of the Sides and Flanks. 



1 ' By the first week in May the summer plumage of the female 

 Grouse is fairly complete, and many of the finely mottled 

 rufous and black autumn flank-feathers are replaced by widely, 

 and often irregularly, barred buff and black feathers, similar to 

 those of the chest. It must be particularly noted that in none 

 of the many females examined, in breeding plumage, were 

 the whole of the autumn flank-feathers cast or changed in the 

 summer moult, a large proportion being retained, unchanged 

 in colour, till the next (autumn) moult. The summer flank- 

 feathers are produced in two ways, either by a gradual re- 

 arrangement and change in the pigment of the autumn feathers 

 (pi. iii. figs. 6-8) or by moult (pi. iii. fig. 9). In some birds 

 the whole of the alteration in the plumage of the flanks is pro- 

 duced by change of pattern in the old autumn feathers, in 

 others the change is entirely produced by moult, while some- 

 times both methods are employed by the same individual. 

 In the former case, the first indication of the coming change 

 may be observed in the beginning of November, or even 

 earlier, when many of the flank-feathers show traces of an 

 irregular buff stripe or spot near the terminal half of the 

 shaft (fig. 7). As the birds only change about half their flank- 

 feathers, these buff marks are only to be observed on such as 

 are destined to undergo alteration of pattern, which, roughly 

 speaking, means every second or third feather. The buff spot 

 gradually enlarges and spreads along the shaft, then becomes 

 constricted at intervals, and breaks up into patches, which 



