RED GROUSE 
species known to occur in the grouse. The latter, as already stated, is the 
cause of one of the two principal diseases. The more slender tape -worm 
{Hymenolepis microps) is also said to some extent to be associated with 
disease and, like the large species, inhabits the duodenum or upper end 
of the small intestine, sometimes in incredible numbers. It disappears 
during the winter-months. Three round worms also exist in grouse, and 
one of them {Trichosoma longicolle) inhabits the duodenum and may prove 
of importance, as it is allied to a form which lives in the human appendix, 
and is at times the cause of appendicitis. Besides the worms, there are 
seven protozoan parasites living in the intestines or in the blood of grouse. 
Most are harmless, but one, a coccidium, already referred to, is the cause 
of disease in young grouse. 
Finally it may be worth mentioning that there is a wide-spread popular 
belief that diseased grouse can be recognized by their beak, colour of their 
plumage and by the lack of feathers on their feet. As regards the former it 
may be stated at once that the colour of the plumage has nothing to do with 
the diseased state of the bird and is purely individual. The feathering of 
the feet is another matter. During the autumn moult every healthy bird 
moults the feathers of the legs and feet between June and August, but birds 
in a diseased state with the moults all retarded may be found moulting their 
leg-feathers between January and March, in which case it is a sure sign of 
disease. 
Hybrids . — ^The red grouse occasionally crosses with the black grouse, 
and much more rarely with the ptarmigan. Hybrids with the former 
species are probably always the result of a union between a blackcock 
and a hen grouse. The males are large and very handsome birds, 
showing very clearly the characters of both parents, the tail being more 
or less forked, and the toes feathered at the base and naked and combed 
at the extremity. 
Apparent hybrids between red grouse and ptarmigan, of which I 
have examined several, are occasionally obtained on the high grounds in 
Scotland in company with birds of the latter species. They show the 
characters of both species, and appear in winter to assume partially the 
white plumage of the ptarmigan. The feeding-ranges of the two species 
practically touch, and there is therefore no reason to doubt that a stray old 
cock grouse inhabiting the higher parts of the moors may occasionally 
pair with a hen ptarmigan. 
W. R. OGILVIE-GRANT. 
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