332 BOARD OF AGRICULTURE. [Pub. Doc. 



the number eaten, it might be impossible for the man in the 

 laboratory, working without exact knowledge of the con- 

 ditions under which the bird was shot, to do either. Many 

 of the larger caterpillars eaten by the smaller birds are not 

 swallowed whole, but picked to pieces, therefore the portion 

 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 larvae, swallowing 

 the smaller ones and pulling the larger ones to pieces, after- 

 wards 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 larvae in forty minutes. 



