72 BIRDS IN THEIR RELATIONS TO MAN. 



canker-worms seventy-five per cent., other caterpillars twenty 

 per cent., and vine-chafers five per cent. Four red-headed 

 woodpeckers had eaten fifteen per cent, of canker-worms, 

 while a single golden-winged woodpecker had eaten only ants. 

 No canker-worms were found in one mourning-dove and two 

 quails. 



Summarizing the above results into one general statement, 

 it is found that one hundred and forty-one specimens be- 

 longing to thirty-six species were studied. "Twenty-six of 

 these species had been eating canker-worms, which were 

 found in the stomachs of eighty-five specimens, — that is to 

 say, seventy-two per cent, of the species and sixty per cent, 

 of the specimens had eaten the worms. Taking the entire 

 assemblage of one hundred and forty-one birds as one group, 

 we find that thirty-five per cent, of their food consisted of 

 canker-worms." 



A comparison was made, in the case of the robin, cat-bird, 

 black-throated bunting, and indigo-bird, of the food in this 

 orchard and that of the species during May under ordinary 

 circumstances. These results showed that there was a gen- 

 eral diminution of vegetable and miscellaneous food in the 

 orchard specimens to compensate for the increase of cater- 

 pillars. 



"Three facts," says Professor Forbes, "stand out very 

 clearly as the result of these investigations : 



" (1) Birds of the most varied character and habits, 

 migrant and resident, of all sizes from the tiny wren to the 

 blue-jay, birds of the forest, garden, and meadow, those of 

 arboreal and those of terrestrial habits, were certainly either 

 attracted or detained here by the bountiful supply of insect 

 food and were feeding freely upon the species most abundant. 

 That thirty-five per cent, of the food of the birds congregated 

 here should have consisted of a single species of insect is a 

 fact so extraordinary that its meaning cannot be mistaken. 

 Whatever power the birds of this vicinity possessed as checks 



