THE WILLOW GROUSE AND PTARMIGAN. 29 



plete by the end of April or beginning of May; also a distinct 

 autumn plumage, which is retained till the following spring. 



To put it more concisely, both male and female have two 

 distinct moults during the year, but in the male they occur in 

 autumn and winter, and in the female in summer and autumn ; 

 the former having no distinct summer, and the latter no dis- 

 tinct winter, plumage. 



In the Willow Grouse and Ptarmigan there are three distinct 

 changes of plumage in summer, autumn, and winter in both 

 male and female alike, the winter plumage being white in all. 



The Red Grouse is considered by most ornithologists 

 merely an insular form of the Willow Grouse, and consequently 

 one might naturally suppose that as the British species does 

 not turn white in winter, such protective plumage being un- 

 necessary in the localities it inhabits, the winter moult has 

 been gradually dropped. Now this is the case with the female 

 only, and we find the male, for no apparent reason, changing 

 his newly acquired buff and black autumn plumage for a winter 

 one of chestnut and black. Further investigations may lead 

 to some explanation of this strange anomaly, but at present we 

 know of none. 



Adult Male.— Autumn Plumage. — After the breeding-season a 

 very complete autumn moult takes place, the quills, tail, and 

 feathers on the feet being entirely renewed. In most examples 

 the feathers of the upper-parts are black, margined and irregu- 

 larly barred with tawny-buff, and in most cases the bars cross 

 the feathers more or less transversely (PI. II., Fig. 4), but in 

 some they are more or less concentric and parallel with the 

 marginal band, giving the upper-parts a scaled appearance. 

 (PI. II., Figs. 6 and 7.) The feathers of the chest are rather 

 widely barred with buff or rufous-buff and black (PL II., Fig. 1 1) 

 and some of the flank-feathers are more narrowly barred with 

 the same colours. The rest of the under-parts vary according 

 to the type to which the individual belongs, being chestnut, 

 black, or white-spotted, or a mixture of all three. In a bird 



