The Food of Birds. 107 



upon a single day's food, or even less, for each bird, we 

 see that these robins were eating at an average rate of at 

 least twenty-six grasshoppers or crickets a day, for seven 

 months, giving us a minimum total of 5,500 Orthoptera 

 for the year. 



Only one per cent, of the food was spiders. Thousand- 

 legs were eaten by eight of the birds, and by these in merely 

 trivial quantity. 



Coming now to the fruits, we find that tame cherries, 

 blackberries, raspberries, currants and grapes, excluding 

 wild fruit of all descriptions, make about one-fourth of the 

 food of the species for the year, the wild fruits making 

 another tenth. In the absence of the latter, the robins 

 would doubtless attack the garden fruits more vigorously.* 

 Concerning these general statements, the all-important 

 question is, of course, the sulficienc}^ of their basis. 



Granting that the observations have been exactly made 

 and correctly generalized, how far may the conclusions 

 reached be expected to hold good in the future? These 

 conclusions actually rest upon the food of a hundred and 

 fourteen birds for probably about half a day each. Can 

 we safely reason from these to the food of the thousands 

 and hundreds of tho\isands of robins of the state, day after 

 day, the whole season through? 



In a paper published last winter in the Transactions of 

 the Illinois Horticultural Society, I made the following 

 reply to substantially the same question : — 



''If the same species will eat substantially the same food, 

 year after year, in the same situation, then, of course, a 

 good deal may properly be inferred from comparatively 

 few data ; but if the food varies widely, either arbitrarily 

 or under slight changes of condition, then we can infer but 

 little. Upon this fundamental question I have two sug- 

 gestions to make. 



"First, if several species allied in structure, occupying 

 the same territory at the same time, living side by side, 



*No man should needlessly sacrifice a wild cherry-tree or a fruiting 

 vine or shrub of any kind. Ordinary common sense would teach the 

 preservation of as much of ihe worthless natural food of frugixorous 

 birds as possible, as a diversion from the cultivated fruits of the orchard 

 and garden. 



