62 Mr. W. R. O. Grant on the 
the ‘Field’ (21st Nov., 1891, and 9th April, 1892), I pointed 
out that the true sexual differences in the plumage of the Com- 
mon Partridge (Perdix perdix) had been entirely overlooked, 
and that the chestnut horseshoe mark on the breast, generally 
supposed to be a distinctive character between the male and 
female, was of little or no value, being largely developed in 
the great majority of young female birds of the year. The 
only reliable character for distinguishing the sexes was to be 
found in the markings of the lesser and median wing-coverts. 
The longitudinal buff shaft-stripe in these feathers is well 
defined in both sexes, but the females have the ground-colour 
blackish transversely barred with buff, while in the males 
(except in the feathers of the first plumage) these markings 
are always absent, and the whole feather is sandy buff, finely 
mottled and vermiculated with blackish, and blotched with 
chestnut on one or sometimes on both webs. Very young 
males in the first plumage resemble the female, but the 
chestnut-blotched lesser wing-coverts of the adult plumage 
are among the first to appear, so that one can easily distin- 
guish the two sexes at a very early period of their existence. 
During the preparation of the twenty-second volume of the 
‘Catalogue of Birds,’ I have been enabled, through the kind- 
ness of numerous friends, to add enormously to our series of 
British game birds, so that, at the present time, the British 
Museum series of Perdix perdix and Lagopus scoticus are 
fairly complete. In the present note I wish to submit some 
extremely interesting and important facts concerning the 
latter species, the like of which, so far as I am aware, are 
without parallel in ornithology. My present remarks are the 
result of nearly a year’s careful study of the changes of 
plumage in the Red Grouse, during which I have gradually 
obtained from various sources the necessary specimens repre- 
senting the different male and female plumages throughout 
the entire year. 
When | first examined our very incomplete series, I had 
little doubt that my present conclusions were correct, but the 
chain of evidence was then too incomplete to speak with the 
absolute certainty I can at present. 
Mr. J. G. Millais (Game Birds and Shooting-Sketches, 
pp. 69, 70 [1892]) gives a most excellent and complete 
account of the various changes of plumage undergone by the 
Ptarmigan (L. mutus) during each month of the year. ‘These 
changes are of three kinds :—firstly, those caused by three 
distinct partial moults, which occur in spring, autumn, and 
winter in both male and female; secondly, those produced by 
a change of pattern in the feathers themselves, which is 
