65 



STRAY NOTES ON GEOUSE AND THE GROUSE- 

 DISEASE. 



So many able scientists and experienced observers have 

 discussed the subject of grouse-disease, and promulgated 

 theories (many of them at variance, and none apparently 

 conclusive), that the writer hesitates to express any opinion 

 as to its exact origin. One circumstance, however, appears 

 to be invariable, and to be the inevitable precursor of disease, 

 viz., a heavj" stock of grouse. I have never myself known of 

 an irruption of disease except after more or less plentiful 

 periods, though it may occur. Certainly it is the inevitable 

 consequence of an undue plenty ; the cycles are almost regular 

 — plenty and scarcity in constant sequence, though the 

 periods of each vary. 



Different areas of moorland vary greatly in their power of 

 sustaining a head of grouse. Thus, on a hill range in Perth- 

 shire or Aberdeen, every acre may accommodate (say) two or 

 three grouse, while in the lowlands, or in Northumberland, 

 one grouse to three or four acres may be a full stock. But 

 each moorland area has its fixed capacity, and, whatever the 

 local maximum may be, when it is exceeded disease is the 

 inevitable result. 



This variation in grouse-productive or sustaining power is 

 exemplified in the north of England by the immense head 

 of game which in some years is attainable in North 

 Yorkshire and the adjoining moors of Durham. The deep 

 peat deposits and rich heather of Teesdale in Yorkshire, and 

 of the "Weardale hills in the adjacent county of Durham, are 

 vastly more prolific of gi-ouse than are the more alluvial moors 

 of Northumberland, extending northwards along and across 

 the Scottish border. In these latter districts the heather is 



