10 THE GROUSE IN HEALTH AND IN DISEASE 



of a heavy snowfall while the birds are sitting does not appear 

 to produce the number of unhatched clutches of weather- 

 bleached eggs which might be expected. Sometimes, no doubt, 

 matters reach the limit of endurance when, urged by the pangs 

 of hunger, the hen is forced to wander away in search of food 

 and grit, and on her return finds all trace of her nest buried 

 beneath a smooth, white drift. Even in this case all is not 

 lost ; the snow fortunately does not lie long in the months of 

 April and May, and in due time she recovers her nest and 

 resumes her domestic duties. It is recorded that in 1908, 

 on a Midlothian moor, a heavy snowfall during laying-time 

 covered the nests to a depth of 9 inches for a period of ten days ; 

 many eggs were lost, some even being laid on the top of the 

 snow ; in many cases the hen bird returned to her nest after 

 the snow had gone and laid more eggs beside those which had 

 been covered some of these birds hatched out every egg. 

 Other cases have been reported where the eggs were covered 

 with snow for so long that their colouring matter had dis- 

 appeared, and yet they produced a healthy brood. 



From observations made upon Grouse in captivity it appears 

 that during the period of incubation the hen will often leave 

 her nest for several days at a time, for no apparent reason, 

 and will return again and hatch out the whole clutch this 

 power of absenting herself without disaster to her eggs must 

 under natural conditions stand her in good stead when the 

 severity of the weather makes the task of incubation unendur- 

 able ; but it is only in the earlier part of the sitting season 

 that her absence is unattended with risk, for once circulation 

 has commenced in the embryo chick the eggs must not be 

 allowed to become cold. Only when the hen is forced to leave 

 the nest on account of heavy rain is there a danger of her 

 deserting the nest permanently three days of incessant wet 

 will suffice for this. 



Another danger to which the eggs of Grouse are liable 

 is that of being destroyed by frost while the hen bird is off the 

 nest. This danger is greatest during the period before the 



