DIET 221 



for this may possibly be found in the variation in abundance and availabihty of foods or in 

 the presence or absence of highly desirable substitutes. Thus one finds that thornapples. im- 

 portant in New England and New York, apparently are not much taken according to Pennsyl- 

 vania reports. Conversely, in the states to the south of New York, where oak (particularly 

 scrub) is more abundant, acorns are commonly ]jreferred to beechnuts, which with us are a 

 much more important food. Even such stand-bys as the cherries lose their significance in 

 Virginia and Wisconsin and are re])laced by greenbrier and clover, both of which while pje- 

 sent are taken to only a limited degree in New York. 



There is real significance in the number of widely distributed plants, which for one reason 

 or another rank high as grouse foods in various regions. Physiologically and psychologically, 

 the grouse seems well able to adapt itself to a wide variety of foods. 



Food of thk Yoiing 



Variations in the food of chicks over the sunnner months is portrayed in figure !!!. Al- 

 though, when adult, the grouse is |)rimaril\ a jdanl eater, a striking characteristic of its 

 food habits is the reliance of the chicks upon injects during the fir.*t week or ten days of 

 their existence. Analysis of the food of .S40 specimens, representing ihe iirood period, in- 

 dicates that 70 i)er cent of the fond of the first luo weeks is insects, in contrast to 30 per 

 cent during the ihird and fourth weeks. By August ihe prnportiori h;i< dro|)pe<! to only 

 5 per cent. 



Possibly attracted 1)\ mo\cinint. the chick iiia\ lake an ant or a spider a.« its first morsel 

 of food. These are likely to be picked up within three to six hours after hatching. Ants 

 remain the most common insect food for .several months. 



As the chicks mature, their utilization of plant foods increases markedly, until by the 

 end of August it approaches that of adults. 



During the sunmier it is normal for crops to be filled with a mixture of plant and animal 

 material. Only nine birds were collected, all before the 1.5th of June, which had fed ex- 

 clusively on insects. In contrast, seven had fed on plant material alone and 6.5 others con- 

 tained only a trace of animal matter. None of these vegetarians were collected before the 

 middle of June, and more than one-half were taken during August. 



As the chicks turn their attention to plants, a lendenc\ to sample man\ kinds but to con- 

 centrate on a few becomes apparent. Sedge seeds together with strawberries make up 26.5 

 per cent of the June plant foods and with blackberries 5o..5 jjer cent of the Julv fare. In August 

 dependence on staples is still more pronounced, blackberries and cherries constituting 65 per 

 cent of all plant food. At this time of year they pay more attention to herbs, such as violets, 

 and to smaller seeds, as those of sedges, than do the adults, but e\en young chicks will oc- 

 casionally take items more characteristic of the food of their parents. Thus, a chick taken July 

 6, had eaten four whole oak buds and the remains of several others were in its stomach. 

 Chicks like the adults sometimes take a considerable variety, as indicated by a late July bird 

 from Essex County which had eaten 1.500 sedge seeds, 44 capsules and 637 seeds of violets, 

 eight fruits of pin cherry, five of viburnum and a few seeds of 11 other species of plants, 

 as well as a snail and 11 different kinds of insects. 



Principal Chick Foods 



Among the plants the really important sources of food for young grouse are sedges, rasp- 

 berries and blackberries, strawberries and cherries. Apparentlv patronage of these four 



