LOCAL CONDITIONS AND HEALTH OF GROUSE 297 



(6) Strongylosis is probably caused by insufficient or inferior 



food during the months of February to April rather 

 than by any particular weather conditions at the date of 

 the attack. Insufficient food causes the winter feeding 

 areas to be restricted, and so the ground becomes 

 heavily contaminated with the Strongyle worm. 

 Weather conditions may indirectly affect the case, 

 but to what extent cannot be stated with certainty. 

 Heavy snow would doubtless be beneficial by covering 

 certain feeding areas and keeping them uncontaminated 

 until the snow has melted ; on the other hand, it would 

 tend to further restrict the feeding areas so long as it 

 lay on the ground. It has been thought that heavy 

 rain might be beneficial as a means of purifying the 

 ground, but experiments have proved that the larvae 

 of this worm seem to flourish best in damp surroundings. 

 Frost and dry cold may do something to suspend the 

 vitality of the larvae for a time, but drought is the only 

 climatic condition which appears to do it any per- 

 manent harm. 



(7) Coccidiosis as a disease in Grouse chicks has only recently 



come under investigation, and the study of the subject 

 is attended with much difficulty. From experiments 

 in the laboratory it has been found that the Coccidium 

 develops most rapidly under conditions of warmth 

 and drought, and it is certain that in the hot, dry 

 summers of 1908 and 1911 there was a marked loss of 

 Grouse chicks. In the former year the cause of such 

 loss was apparently undetermined, or at least only 

 suspected, but in 1911 Grouse chicks, picked up dead 

 on the moors, were found to be heavily infected with 

 coccidian cysts. 



(8) The foregoing Reports have established a clear connexion 



between a good heather year and a healthy stock the 

 following spring. 

 It may be thought that the foregoing observations are of 



