Food and Water 113 



variation in different areas to make such a ranking of much value. 

 However, it is apparent that some are of greater utility than others. 

 The question of palatability is discussed later. Suffice it here to say 

 that if adequate quantities of these twenty-five groups are readily 

 available, the food situation on a grouse range is not likely to be a 

 limiting factor. Figure 8 shows the months during which these foods 

 are of primary importance (solid bar) and of secondary importance 

 ( dashed bar ) . 



THE TWENTY-FIVE PRIMARY GROUSE FOODS IN 

 THE NORTHEAST 



The BmcHES (Betula) 



Species utilized: yellow birch {B. lutea), black or sweet birch 

 (B. lenta), paper birch {B. papyrifera) , giay birch (B. populifolia) , 

 river birch {B. nigra), listed in approximate order of importance 

 (see Plate 20C). 



Seasonal importance: most important as a winter and early-spring 

 food, reaching the height of utilization in February and March; 

 taken in increasing quantities from late September on to the mid- 

 winter peak, and in rapidly decreasing quantities after midspring. 



Parts used: Almost entirely leaf buds; slight use of catkins and 

 seeds. 



Geographical importance: Northern New England, New York and 

 Pennsylvania constitute the region of greatest use of birch. The 

 range south of Pennsylvania and in southern New England pro- 

 vides little of the three more valuable birch species and reflects 

 this deficiency in low utilization records. The gray birch, most preva- 

 lent in southern New England, is relatively unimportant as a source 

 of grouse food. 



The birches, particularly yellow, black, and paper, are one of the 

 groups of trees and shrubs which through their readily available and 

 palatable buds enable the grouse to survive the rigors of winter in 

 the northern portions of its range without difficulty. Utilization 

 within the genus is partly determined by availability, partly by selec- 

 tivity. Yellow and black birches, and to a slightly lesser degree paper 

 birch, are highly palatable. Their use by grouse is mainly determined 

 by their abundance and distribution. Gray birch, and probably river 



