54 The Natural History of British Game Birds 
Goniodes tetraonis and Nirmus cameratus. In the ileum were found five specimens of the larger and 
more common tape-worm of grouse, Davainea calva ; in the duodenum numerous specimens of the 
minute threadlike cestode Hymenolepis tetraonis. The caeca were literally teeming with millions 
of the extremely small and slender round worm Strongylus pergracilis. The blood contained, in 
addition to putrefactive bacteria and to the larva? of Filaria smitki already mentioned, large 
numbers of Leucocytozoon lovati, a protozoal organism quite recently discovered by Drs. Selio-mann 
and Sambon in the red grouse. 
"The bird in question was picked up alive by a retriever, and sent to us as suffering from 
'grouse disease.' It was somewhat emaciated; the plumage was dull, the feather stockings were 
partly rubbed off, the combs were pale. The lungs showed very slight, if any, congestion, the liver 
was dark round the edges and rather softer than normal, the spleen seemed normal, the preventri- 
culus was somewhat congested, but the caeca and intestines were normal in colour and appearance. 
The bird was a cock, and the testicles were fully developed. This grouse was evidently dying of an 
acute disease. The tape-worms it harboured were certainly not the cause. Both Davainea calva 
and Hymenolepis tetraonis may be found in far greater numbers in apparently healthy birds. The 
same may be said of Strongylus pergracilis, though Cobbold, who discovered this entozoon, 
believed it to be the cause of the grouse epizootic he investigated in 1872. Like Davainea calva, 
Strongylus pergracilis is found almost in every bird. In the present instance, though extremely 
abundant, it appeared to have caused no appreciable lesion. The caeca seemed perfectly normal. 
As to the microfilaria;, they have no pathogenic importance. 
" Dr. Sambon is inclined to consider the Leucocytozoon as the most probable cause of the bird's 
condition. Since the discovery of this parasite by Dr. Seligmann and himself, he has found it in 
three other birds, including the one here mentioned. The leucocytozoa have a very complicated 
and as yet very imperfectly understood life history. Like the malaria parasites of man, they present 
an alternation of generations, together with a change of hosts. The ' vegetative ' or asexual cycle 
of Leucocytozoon lovati occurs in the blood and bone marrow of the grouse ; the sexual cycle, 
according to Sambon, is probably spent in the body of the grouse fly (Omillwmyia lagopodis), a 
parasitic fly of the family Hippoboscidce, which appears to be strictly limited to the red grouse." 
The Grouse Disease Committee issued an interim report in the autumn of 1908. 
Their observers stated that during 1905, 1906, and 1907, no instances of death from 
the acute pneumonia form had been noticed. All birds sent to them in 1908 died 
as the result of internal parasites. 
The usual length of flight is about half a mile to a mile. When about to alight 
Grouse look about to see if any of their kindred are to be seen, and call to them, 
and if the survey is satisfactory, they quickly swoop round and pitch beside them. 
Single males nearly always give a little rise in the air at the last moment and flutter 
to the ground, uttering their cheery cry. The point of alighting is usually a rising 
knob from which a good view to the front may be obtained. Here they sit and watch 
for a few minutes, and if they see a move in the " butts " ahead they will generally 
break back on being flushed. I have known Grouse come into a shooter's butt and 
settle round his legs. Scared by a hawk a covey of Grouse came into my brother's 
butt during a drive in Aberdeenshire, and refused to leave. As a rule Grouse on flat 
moors or sloping hillsides go straight ahead and are not difficult birds to shoot, but 
when curling through a pass and "falling" into the next valley they are among the 
most difficult birds to hit in existence. I never think of this without calling to mind 
a wholesome anti-conceit tonic I received one day at a certain pass at Corriemuckloch 
in Perthshire. In the previous drive I had only missed one shot, getting twenty-two 
birds, and was feeling just as a man does under such circumstances. In the next 
