The Audubon Societies 321 



observers that they do"; still, there must be other causes for their departure 

 in the fall, though just what these are is not definitely known. The more we 

 learn al)()ut the food-habits of birds, the nearer we may come to the truth, 

 because food is the first chief necessity for the existence of any organism. 



The food of most birds \aric's sonuwlial with the seasons, and with the 

 locality where they are indi\iduall}' distributed. In general, any single species 

 seems to have a preference for certain kinds of food, and usually this prefer- 

 ence is governed by some special adaptation for getting particular foods. 

 Although a Downy Woodpecker in one locality might happen to sample a mul- 

 berry in July, it would be odd enough to think of Downy Woodpeckers every- 

 where living on mulberries, because Woodpeckers, as a family, are fitted with 

 special tools for getting boring-insects and larvae from under the bark of trees. 



It would be even more difficult to imagine Warblers and Vireos chisel- 

 ing for food, as the Woodpeckers do, although both of these families of birds 

 seek their food on and about trees or shrubs. Neither one, however, eats fruit 

 with much more relish than the Woodpeckers, at least in localities where 

 insect-food to their liking is abundant. Indeed, I have watched a variety of 

 seed- and insect-eating birds regale themselves in midsummer upon mul- 

 berries and cherries, but never once have I chanced to see a Vireo or a Warbler 

 touch these fruits. A Red-eyed Vireo of my acquaintance visited a dogwood 

 bush regularly until it was cut down, and most industriously nipped off the 

 small, dry, purple berries. Very likely, other Vireos may relish a change from 

 their accustomed diet of insects; I do not happen to know, which is all the 

 more reason that I should watch Vireos, and Warblers as well, in different 

 places and at different times of the year. A great deal remains to be discov- 

 ered by the patient observer. 



And this leads to the suggestion that we begin our study of birds this fall 

 by taking up the different kinds of food available for them in our own vicinity. 

 In order to really get at something definite, we would do w^ell to catalogue 

 these foods in a simple way as follows: 



In filling out this table, it would be a help to classify the dift'erent foods by 

 describing their condition at the time they are eaten by birds. Thus, under vege- 

 table food there are buds, blossoms, leaves, seeds and fruits in great variety; 

 under insect food, eggs, larvae, pupae and adult insects, while under animal 

 food, there are immature and adult worms, mollusks and sand-fleas, etc.; 

 among invertebrate creatures, besides field-mice, gophers, moles, prairie-dogs, 



