18 THE GROUSE IN HEALTH AND IN DISEASE 



The more usual procedure is that the abdominal patch of autumnal plumage 



is lost during incubation, and is then quickly replaced by a renewal of the 



autumnal feathers when the spring plumage is also beino- shed. 



Peculiar . .... . 



growth on There remains, however, in the majority of birds, a very quaint 



abdomen. 



growth of belated spring plumage, consisting of buff and black- 

 barred feathers in two lines down each side of the centre of the naked 

 patch, as though, for some occult reason, the intention to grow "spring- 

 plumage" feathers upon this area had never been altogether lost. This 

 peculiar persistence of belated intention shows itself as a patch of yellow 

 feathers made up of the two lines of feather growth in the midst of a much 

 broader area of the autumn red pigmented feather which one would expect 

 to find all over the abdomen (PL xiv,). It is conceivable that a small 

 persistent remnant such as this, having no obvious connection with the 

 surrounding plumage at the time, or with the habits of the bird, or with 

 the seasons, may yet have something to do with the third or lost " eclipse " 

 plumage which is still to be found in the grey plumage of the Ptarmigan, but 

 is almost completely lost in the case of the Red Grouse. 



In July the summer plumage of healthy hens is much worn out, 

 frayed at the edges, and very definitely faded, and the feathers are already 

 dropping out. On the chin, throat, and fore-neck, new red feathers of 

 the autumn plumage, looking rich and dark, are already making their 

 appearance. The back is as it was, but faded, and the flanks are still con- 

 spicuously broad-barred with buft' and black ; but the abdominal l)are patch 

 is now growing new autumn plumage feathers with great rapidity from the 

 centre outwards. The primaries and secondaries have now commenced to 

 moult. There may be in July, in the hen, as many as six or eight old 

 primaries in each wing with frayed tips, still to be renewed. 



Precocious young birds of the year can still at once be distinguished from 

 hens in moult, because in the former the dark red-brown black-lined autumn 

 Distinction plumagc is ou the flanks, while the broad-barred bufi" and black, and 

 between rather worn-out chicken feathers are in the centre of the abdomen. In 



young and 



old birds, ^^j^g adult the distribution is reversed. The broad-barred buff and 

 black feathers of the spring plumage are on the flanks, and the redder fine-barred 

 autumn plumage is appearing in the centre (compare PI. xii.. Figs, a, c, g, h, 

 k, and n, with Fig. d.). In skin No. 284 there seems to be an unusual compromise 

 in a very backward hen, owing to disease. The compromise is between the 



