38 The Natural History of British Game Birds 
complete, especially amongst the flank feathers, which often begin to change in pattern 
as early as December. With the renewal of pigment much colour is also added to these 
feathers in the early days of spring, and they present a different and warmer tone in 
March when the spring moult is in full flush. The same may be said of the front of 
the neck and chest, where the summer plumage is attained by a mixed colour and pattern 
change amongst old feathers and an accession of new ones. So that, on the whole, it 
may be said that the female gets its breeding plumage by a half moult, and a half pattern 
and colour change. We must not, however, lose sight of the fact that female Grouse 
and other birds vary enormously in individual constitution, and that some being more 
vigorous than others will attain their breeding dress wholly by means of a moult. Mr. 
Ogilvie Grant, who has made a close study of the species, asserts that every female 
attains the whole of the summer dress by means of a moult, but though this may be 
regular, I am not at all convinced that it is the invariable rule. 
Until 1909 naturalists do not seem to have devoted much time to the study of 
the summer plumage of the Red Grouse, probably owing to the difficulty of obtaining 
specimens. Mr. Ogilvie Grant, in his excellent little book on the Game Birds (p. 29), 
considers that the Red Grouse, being an insular form, living in warmer latitudes where 
a white winter dress is unnecessary, has gradually dropped the spring moult necessary 
to his northern relation, the Willow Grouse. And in the main he is right ; but not 
completely so. He states definitely, moreover, that the male breeds in the "winter dress," 
suggesting that there is no accession of new feathers similar to the summer dress of 
the Willow Grouse, and in this he is incorrect. 
Some years ago the proprietor of a deer forest, who was anxious to exterminate the 
Grouse on a certain hill, allowed me to shoot three pairs in May for my collection. I confess 
that parts of the plumage of the male puzzled me, and I was in doubt whether the 
brilliant dress was altogether the result of repigmentation or fresh moult. Some new feathers 
were coming in and others were nearly complete on the neck, and this made me think 
that Mr. Grant's view of the winter-summer dress without additional feathers could not 
be maintained. An opportunity for thorough investigation of the question did not occur 
till 1909, when I applied to certain friends to help me to solve the question. Through 
their generous support I have had over fifty freshly-killed cocks sent to me between 
February 10th and July 1st. To show how difficult it is to get specific information on 
a simple phase in the life-history of one of our commonest birds, I may mention that 
not one of my correspondents or their keepers, who had spent their lives on the moors, 
could state definitely whether the cock Grouse had a breeding plumage, or even a summer 
moult, or not. A typical answer was that of Mr. R. Rimington-Wilson, who writes : 
" I have spent my life on the moor edge, and I am ashamed to say I do not know." 
The result of my examination of these cock birds is as follows : — 
From March 1st until March 24th not one new feather is found in the winter plumage 
of eight cocks from Yorkshire, Elgin, Inverness-shire, and Perthshire, but as the month 
advanced the comb was much developed, and a richer red colour suffused all the red 
feathers of the plumage, which also achieved a brilliant gloss. A considerable pattern 
change was also noticeable. The access of colour is due to repigmentation, consequent 
on the birds getting into a high condition as the snow melted. The first bird to prove 
