62 Mr. W. R. O. Grant on the 



the 'Field' (21st Nov., 1891, and 9rh April, 1892), I pointed 

 out that the true sexual differences in the plumao-e 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 ])erdix 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 gi-adually 

 obtained from various sources the necessary specimens repre- 

 senting the different male and female plumages throughout 

 the entire year. 



When 1 first examined our very incomplete series, 1 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 [1592]) gives a most excellent and complete 

 account of the various changes of plumage undergone by the 

 Ptarmigan {L. mutus) during each month of tlie 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 



