38 THE GROUSE IN HEALTH AND IN DISEASE 



November ; probably always leads to some loss of 

 weight in either sex. 



(d) Courtship, in the male always apparently a cause of 



loss of weight : in the female, owing to increased 

 rest, with some change in the general metabolism 

 and extra opportunities for feeding prior to 

 incubation, seems to lead normally to a very 

 considerable increase of weight. 



(e) Egg laying and incubation, gradually lead to a loss 



of weight, which becomes more marked when the 

 hen has had the care of a family of chicks. These 

 cares, notwithstanding the abundance of summer 

 food, often result in producing the lowest possible 

 weights in hens, such loss of weight being in some 

 cases due to an attempt to rear a second brood. 

 During the hen's incubation the cock recovers 

 his weight, because the food supply is rapidly 

 improving, and because his energies are no longer 

 exhausted by courtship. 



(/) A shortage of good food in a bad winter must often 

 be responsible for a great reduction in weight. 

 Similarly the abundance of food in summer, 

 autumn, and early winter must serve to counter- 

 act some of the other causes of loss of weight. 

 It would be interesting, were it possible to collect sufficient 

 figures, to compare local variation in the average weight of 

 healthy males or females with local differences in the geo- 

 graphical situation, climate, height above sea-level, or the 

 character of the subsoil. Particular districts have been credited 

 with the production of birds distinctly above the average in 

 size and weight. Midlothian, Caithness, and the west coast of 

 Scotland each claim to produce exceptionally heavy Grouse. 



To establish this a much more extensive series of weights 

 should be taken than has hitherto been possible. So far as the 

 Committee have been able to ascertain, it is difficult to say 

 with certainty that any one district produces birds of a definitely 



