﻿292 Canadian Record of Science. 



Within certain limits, birds feed upon the kind of food 

 that is most accessible. Thus, as a rule, insectivorous 

 birds eat the insects that are most easily obtained, 

 provided they do not have some peculiarly disaoreeable 

 property. It is not probable that a bird habitually passes 

 by one kind of insect to look for another which is more 

 appetizing, and there seems little evidence in support of 

 the theory that the selection of food is restricted to any 

 particular species of insect, for it is evident that a bird 

 eats those which by its own method of seeking are most 

 easily obtained. Thus, a ground-feeding bird eats those 

 jt finds among the dead leaves and grass ; a flycatcher, 

 watching for its prey from some vantage point, captures 

 entirely different kinds ; and the woodpecker and warbler, 

 in the tree tops, select still others. It is thus apparent 

 that a bird's diet is likely to be quite varied, and to differ 

 at different seasons of the year. 



In investigating the food habits of birds, field observa- 

 tion can be relied on only to a limited extent, for it is not 

 always easy to determine w^hat a bird really eats by 

 watching it. In order to be positive on this point, it is 

 necessary to examine the stomach contents. When birds 

 are suspected of doing injury to field crops or fruit trees, 

 a few individuals should be shot and their stomachs 

 examined. This will show unmistakably whether or not 

 the birds are guilty. 



In response to a general demand for definite information 

 regarding the food habits of our native birds, the 

 Biological Survey of the Department of Agriculture has 

 for some years past been conducting a systematic investi- 

 gation of the food of species which are believed to be 

 of economic importance. Thousands of birds' stomachs 

 have been carefully examined in the laboratory, and 

 all the available data respecting the food brought 

 together. The results of the investigations relating to 

 birds of prey, based on an examination of nearly 3,000 



