No. 4.] BIRDS AND CATERPILLARS. 333 



The caterpillars were large, and he held them with his foot, 

 pulled out certain inner parts and ate them, discarding the 

 rest. This is a common practice with the chickadees. They 

 hold the larvae 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 caterpillars are dropped accidentally or wantonly destroyed 

 in mere sport is not known, but many are certainly killed in 

 this way. The blue jays' habit 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 obser- 

 vations 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 

 im})0ssible 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 cater- 

 pillars. 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. 



Birds materially restrict the Increase of Hairy 

 Caterpillars. 

 The writer has earnestly endeavored to determine to what 

 extent birds control the increase of hairy caterpillars. The 

 result of the investigation is not as yet conclusive, but much 

 can be deduced from the array of facts presented. 



