Biography 47 



crust but this I have never observed. Knowing the abihty of the 

 bird to go without food for days on end, it is doubtful if this is ever 

 a very serious matter, although it is possible that it may actually 

 happen. 



Snow roosts do make the birds quite vulnerable to attack, espe- 

 cially by foxes. There is always a little breather hole from the birds' 

 heads to the outside of the snow that is often easy to spot. Grouse 

 tracks that end in a slight mound of snow are a sure indication of 

 the birds' exact position. Even a man, if he is skillful, can catch the 

 birds by hand under these conditions. There is good evidence that 

 some foxes learn to catch on to these signs too. 



The proportion of winter roosting beneath the snow varies in dif- 

 ferent years and also with the period of the winter. Winters with 

 little snow will prevent the use of snow roosts to a considerable ex- 

 tent, but other than this limitation of opportunity the degree of 

 snow-roosting depends upon the prevalence of abnormally severe 

 weather, low temperatures and high winds. The first severe storms 

 of the season always induce more snow-roosting than later ones. 

 This appears to be due to the relatively greater change from late 

 fall weather, whereas in the later storms the change in conditions 

 is not as marked and the birds have then become accustomed to 

 the hibernal extremes. 



Gregariousness. The ruffed grouse is not a gregarious bird in the 

 full sense of the word: living in flocks. However, it does exhibit vary- 

 ing degrees of cohabitation with those of its kind. It has already 

 been noted that in the early spring there is a shuffle from the winter 

 groupings to the male and female breeding territories. Thus, in the 

 spring there is an almost complete loss of the gregarious tendency. 

 We have noted two females nesting concurrently within fifty feet 

 of each other on occasion. Two females occasionally lay in the same 

 nest although, so far as we have been able to ascertain, only one 

 bird does the incubating. Aside from these definitely abnormal as- 

 sociations, we may say that the species is solitary throughout the 

 spring period. 



During the summer two males are quite often found together, or 

 a male and female that has no brood. It has already been noted 

 that a male is occasionally found associating with a brood, although 

 this is hardly an example of flocking. Several cases were observed of 



