Shelter 93 



toward evening. The variations in use of other types are less notable. 

 A rise in use of conifers toward evening is contrary to the previous 

 season's trend. 



Summer adjustments complete the shifts in daily cover type use. 

 Slashings show a notable increase in use intensity from morning to 

 night. Mixed woods has a high use intensity at midday with 

 markedly lower use in the early day and again towards evening. 

 This is complementary to the trend in use of overgrown land, which 

 is high in morning and evening and low at midday. In summer, the 

 use of conifer woods is not important. 



The reasons for these movements from one cover type to another 

 during the day are linked with the birds' habits, although often 

 conditioned by the weather. Thus the habit of feeding in early 

 morning takes the bird from its night roost, usually conifers or mixed 

 woods except in summer, into the types that furnish food, usually 

 the deciduous types. However, if the weather is inclement, this nor- 

 mal habit will likely be altered temporarily; the bird either gets 

 some food in its protection cover or delays feeding for some hours, 

 or even days, until tlie weather is better. The requirements for sun- 

 ning, dusting, drumming, and nesting similarly stimulate quick 

 movements from one cover type to another for the purpose of the 

 moment. To provide adequately for these vai-^ing needs within easy 

 daily range, the range must provide not only the needed types of 

 cover, but also have them interspersed intimately enough for ready 

 accessibility. Upon these needs must be built any effective plan for 

 range management. 



THE EFFECT OF SLOPE ON SELECTION OF 

 COVER BY ADULT GROUSE 



Slope bears numerous relations to cover and to the acceptability 

 of cover under various conditions. The steepness of a slope may 

 impede the bird's mobility, or aid it. When on level ground, a grouse 

 moves about on the basis of its horizontal flight capability. With 

 increasing steepness of slope, it requires more power to go uphill 

 and maintain speed and less power to go downhill; that is, it loses 

 speed when ascending, and gets additional velocity when "power 

 diving." Whether a bird desires to go uphill or down when on a 

 given slope may depend considerably on the location of cover types. 



