1006 DR. E. A. WILSOX OX THE [Juiie 14,. 



the rule, mul the rule of health becomes almost the exception. 

 It is a very difficult matter, iiuleed, for anyone who has not 

 had the oppoitunity of examining an extensive series of Gi'ouse- 

 skins, in disease as well as in lie^dtii, and covering every month 

 of the year, to come to any true conclusion aljout the moult. 

 Diseased conditions often entirely mask the normal plumage- 

 changes from time to time, and it is far more important to 

 realise this than to examine thousands of more or less healthy 

 birds shot in the ordinary course of events in the shooting- 

 season. A study of alinormal plumage-changes in disesised Grouse 

 is essential if the discrepancies which arise in the moult of 

 what are often wrongly considered normal birds aie ever to be 

 explained. Once this point is grasped tne question becomes much 

 simpler ; and it is because the Grouse Disease Committee has had 

 such a unique opportunity for studying both sides of the question 

 that it has been deemed necessary to enter into these plumage- 

 changes at such length. 



The legs and feet of a healthy bird in April should be getting 

 worn and thinly feathered. If a bird has newly and thickly- 

 feathered legs and feet, it means, almost certainly, that the- 

 " winter " plumage has been put on very late. The healthy 

 Grouse should now be moulting the feathers of the feet and legs, 

 so that bareness or lack of feathers becomes in them a sign of 

 health in April and thickly- feathered legs a sign of sickness; 

 this is the precise contrary of what has almost become pioverbial 

 on the mooi', that bare legs indicate disease ; though for the later 

 autumn months the saying is quite true. 



In il/rt// the preponderance of cock bii-ds found dead, and there- 

 fore of skins of cock birds in the May collection showing ))elated 

 moult, is again a large one. The healthy cock is still in his- 

 much-worn winter-plumage, but on the head and neck some 

 feathers of the new autunni-plumage are l)eginning to make their 

 appearance (Pis. LXXXIIl. & LXXXIV.). 



In June the disease mortidity, due to Stiongylosis, is, as a ride, 

 coming to an end. This at least is true for the adults, but for 

 the young chicks June and July are often fatal months owing to 

 Coccidiosis. Late in June the healthy cock Grouse can at last 

 be said to have changed into his complete "autunni-plumage." 

 The winter- plumage persists only on the abdomen and lower 

 breast, on the actual chin which is blackish, with a few white 

 spots, and on the throat, where a few led feathers still remain.. 

 The mouhiug of the <piills and tail-feathers commences towards 

 the end of the month The lump and back are now completely 

 covered with new black-centred feathers carrying broad-barred 

 bnfi' and black bands and a few have a whitish terminal spot^ 

 similar to that found in the female. 



The head and neck, l)iea.st and throat, are now clothed with 

 broad- liaried buff and black feathers, quite distinct from the more 

 chestnut and more finely black-marked plumage of the winter. 

 It is impossible, in seeing a series of the birds showing this dis- 



