50 The Natural History of British Game Birds 
but it is the fall of snow followed by a thaw and then by hard frost which causes 
emigration with late Grouse for great distances to where the conditions of life are 
possible. The passage from high to low ground in winter can hardly be called a 
migration, as most of the birds return in spring, but after a big winter movement 
extending to a great distance it is doubtful if many of the wanderers reseek their 
place of birth. Local movements are common in Perthshire and Strathspey. During 
some winters certain low grounds are swarming with birds, which rapidly eat up all 
the food, and take the first opportunity to return to the high hills where fresh food is 
more easily to be found. In consequence, it is found that after the breeding season 
the high beats are much better stocked than the lower ones. 
Again, local migration may be caused by drought, for water is very essential to 
Grouse, and they will desert a moor very soon that does not hold a good supply. All 
the best moors in Scotland are well watered, and owners of dry moors will do well to 
create artificial supplies if they wish to hold their stock. 
All men who think, and have had experience as well, must see that the over- 
stocking of moors is the main cause of the Grouse disease. It is impossible to keep a 
great number of birds or animals in good health if the condition of their food supply 
is insufficient. No moor can carry more than a certain number of Grouse, and when 
this number is exceeded disease, due to an improper diet, is bound to begin, and then 
rapidly to spread. 
As I have often stated, volumes may be written and newspapers flooded with opinions 
as to how to improve Scottish deer and Grouse, but nothing will be done (except locally) 
as long as the individual selfishness of man exists, and that will be to the end of the 
chapter. There are too many conflicting interests to be studied. A landlord who does 
not know the fluctuating conditions of his moor says to his tenant, "You must not 
shoot more than a certain number of brace of Grouse." That is doubtless correct for a 
certain number of seasons. But the tenant, if an intelligent man, has meanwhile been 
improving the moor every year, and one year he obtains a large stock of birds, larger 
than the moor can hold. He is still restricted to his 500 brace, let us say, when 
properly he should kill 1500 brace. The landlord, however, says No, only 500 brace 
are to be shot ; and so when the winter comes those extra thousand or two of Grouse 
must be forced to live on old worn-out heather and other unsuitable food, or starve. 
Thus when spring comes this moor, and probably the adjoining one, where similar 
conditions have prevailed, will be a prey to disease. It seems true that the only 
preventive to the evil is a wholesale slaughter in bumper years. Every Grouse that 
can be killed should be shot before December 10th, and then both the tenant and the 
landlord would ultimately benefit. 
The management of Grouse moors is now so well understood that little need be 
said on the subject. In a really well-kept moor there should be no heather over a foot 
high, except in a few places for shelter ; and it is well to remember that when once the 
moor is brought into good condition only small patches of heather a few yards square 
ought to be burned. This forms numerous and scattered feeding grounds, especially 
for young birds, whilst, at first, these bare places are excellent spots where they may 
sun and dry themselves, a very important point for half-grown Grouse. Plenty of 
