28 



BULLETIN OF 



Massachusetts Board of Agriculture. 



BIRDS AS DESTROYERS OF HAIRY CATERPILLARS. 



By E. H. Fohbush, Ornithologist to the Board. 



*t,- i ne * SP e in !L day ' lon £ ^ ears a S ' a vireo sang in a sunny, swampy 

 thicket. Suddenly the bird ceased its song, leaned forward, ran along 

 the limb, picked a large caterpillar from a twig, pecked it a little, 

 swallowed it and resumed its song. 



A small boy, a witness of the act, followed the bird closely, and saw 

 that during each intermission of the song it was occupied either in 

 catching caterpillars or other insects on the twigs and leaves, or in pur- 

 suing flying insects through the air. 



Previous to that day birds had interested the writer principally be- 

 cause of their beauty and song, but this incident opened a new field for 

 study, the pursuit of which has since convinced him that birds as a class 

 excel all other animals as destroyers of those insects which feed upon 

 vegetation, and that the species of plant-feeding insects which escape 

 decimation by birds, at one time or another, are very few as compared 

 to the total number of such species in existence. 



In such research as the writer has been able to make in agricultural, 

 ornithological and entomological literature it has become noticeable 

 that certain insects are supposed by many writers to be protected by 

 prickly hairs or spines from the attacks of birds. 



This astonishing error, for which there is really very little excuse, 

 has been repeated, in one form or another, by writer after writer during 

 the present century, and is still persisted in. No less an authority than 

 the late Prof. C. V. Riley, for many years entomologist to the United 

 btates Department of Agriculture, has assisted in the promulgation of 

 this belief. The most positive statements have been made to the effect 

 that birds do not eat hairy caterpillars, although here and there an ex- 

 ception to the rule is named. Among the earliest of these statements 

 now at hand is one from a writer in the " Annales de lTnstitut Horticole 

 de Iromont,;' vol. 5, p. 311, published in Paris in 1833. 



In discussing the opinion promulgated by the Natural History Society 

 °l , {j . ol ' ht f ' that the diminution of fruits is on account of the diminution 

 ot birds, he places the caterpillar of the gvpsy moth at the head of the 

 list ot injurious caterpillars, saying, "that above all it is very essential 

 that it be destroyed." He says further that as these caterpillars are 

 armed with long hairs the birds guard well against bringing them to 

 their young and that in twenty years of observation he has not seen a 

 single example. He also states that these insects when in the chrysalis 

 are not sought by birds. 



Statements like the above have been received without question, and 

 the inferences and conclusions drawn by the earlier writers appear to 

 have been accepted and promulgated by others. In recent years, how- 

 ever, more accurate knowledge seems to have been gained by a few 



