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birds are not swallowed whole, but picked to pieces. Therefore the por- 

 tion of the caterpillar swallowed would be entirely unrecognizable when 

 found in the bird's stomach. Other caterpillars are dissected, as it were, 

 by the bird, and only the internal parts chosen as food. These cannot be 

 identified in the bird's stomach. Orioles, vireos, warblers, titmice and 

 tanagers are among the birds which commonly dissect caterpillars in 

 this way. 



This is not a rare or exceptional habit, nor is it difficult to observe. It 

 seems to be a device adopted by the smaller birds mainly when feeding 

 on the larger caterpillars. These caterpillars are probably too large to 

 be swallowed whole by small birds without causing some inconvenience, 

 so they choose the parts which can readily be digested and reject the 

 others. 



Wilson Flagg says that he saw an oriole in a black cherry tree kill in 

 one minute seventeen caterpillars, and noticed that the oriole did not 

 swallow the insect, but set his foot upon it, tore it asunder and swallowed 

 an atom taken from the inside. " Had he eaten the whole caterpillar," 

 says Flagg, " three or four would probably have satisfied his appetite. 

 But the general practice of birds that devour hairy caterpillars is to eat 

 only a morsel, hence they require greater numbers to satisfy their wants." 



Mr. Mosher records an instance where a red-eyed vireo came into a 

 tree, taking brown-tail moth larvte, swallowing the smaller ones and 

 pulling the larger ones to pieces, afterwards swallowing some of the 

 pieces. He saw it eat fifteen in the eight minutes it was in sight. 



The warbling and yellow-throated vireo have often been observed to 

 do this, though the habit is not constant even with individual birds. 



_ A red-eyed vireo was seen to take a forest tent caterpillar, beat it with 

 his bill, pull it to pieces and eat all the pieces. The next one was treated 

 in the same way, except that he ate the inside only, dropping the skin 

 and head to the ground. 



Another red-eyed vireo was seen to eat seventy-three gypsy moth 

 larva? in forty minutes. The caterpillars were large and he held them 

 with his foot, pulled out certain inner parts and ate them, discarding the 

 rest. 



This a common practice with the chickadees, They hold the larva? 

 with their feet mainly, tearing them open and devouring a portion or 

 all of the internal parts, leaving the head and skin untouched. 



From personal observation and corroborative facts obtained from 

 other observers I am led to believe that this is a habit with many birds. 

 The crows, jays, chickadees and some of the woodpeckers also have the 

 habit of killing caterpillars which they do not eat. Whether the cater- 

 pillars are dropped accidentally or wantonly destroyed in mere sport is 

 not known, but many are certainly killed in this way. 



The habit of the blue jays of pecking caterpillars and dropping them 

 to the ground has been previously noted by Dr. C. M. Weed in the ninth 

 annual report of the Ohio Agricultural Experiment Station in quoting 

 from the observations of Mr. E. V. Wilcox. 



Different species of warblers have also been seen to eat portions of 

 the larger caterpillars, leaving the external parts A black-and-white 

 warbler was seen to beat a forest tent caterpillar on the ground 

 until she had torn it in pieces, when she took the inside parts and flew 

 away to her nest, leaving the remainder on the ground. She did not 

 return for the parts left. 



These things can be learned only by observation, and it will be readily 

 seen that when birds feed in this way it is impossible for one examining 

 the stomach contents to get, by this method alone, an accurate or even 

 an approximate idea of the value of the bird as a destroyer of hairy 

 caterpillars. Birds cannot feed to any extent on hairy caterpillars 

 where such larvae are few, and unless the dissector knows whether such 

 caterpillars were obtainable where his birds were taken, he cannot form 

 an accurate idea of the value of the bird in this respect. 



