SUPPRESSION OF PESTS BY BIRDS McATEE. 423 



wren feeding on the caterpillars. The maples in front of the house have been 

 filled with warblers, all of which were very busy with the trunks and branches, 

 and yesterday I noted five varieties. 



On May 26 she states : 



We have practically no forest tent-caterpillars in town. They hatched in 

 large numbers, but the cold evidently killed many and the birds appeared to 

 nave cared for the remainder. 



Even so tenacious a pest as the gipsy moth is not always proof 

 against losses due to birds. E. H. Forbush states 25 that — 



Instances were recorded during the State [Massachusetts] campaign against 

 the gipsy moth, from 1S90 to 1895, where small isolated moth colonies appeared 

 to have been suppressed and even annihilated by birds. A serious outbreak 

 was discovered in Georgetown, Massachusetts, in 1899. It had been in ex- 

 istence for a long time, but its spread had evidently been limited by the great 

 number of birds that were feeding there on all forms of the moth. Several 

 months later the State abandoned the work against the moth and little hope 

 was entertained that anything more than a severe check had been given the 

 insect in Georgetown. Nevertheless, in the six years that have since elapsed 

 comparatively few moths have been found in that locality. The most feasible 

 explanation of this seems to be that up to 1906 the birds have kept the numbers 

 of the moths below the point where they can do appreciable injury. 



It has frequently been remarked that few birds attack any stage 

 of the tussock moth (Hemerocampa leucostigma) , but the English 

 sparrow, the Baltimore oriole, and yellow-billed cuckoo are known 

 to eat the larva, and the hairy woodpecker, according to Dr. E. 

 Sterling, of Cleveland, Ohio, sometimes is an extremely effective 

 enemy of the tussock moth or, as he calls it, the New Haven elm-tree 

 caterpillar. Doctor Sterling says: 20 



In the summer of 1880 the elms along Euclid Avenue, especially in my vicinity, 

 were attacked by the " New Haven elm-tree caterpillar." Fearing a repetition 

 of their trouble, numbers of us fought the cocoons in the fall and destroyed 

 thousands, but when winter set in tens of thousands still remained on the outer 

 branches beyond reach. About the 1st of December a pair of hairy wood- 

 peckers (Dryobatcs villosus) made their appearance and fed daily on the grubs; 

 in the course of that month and the next over a dozen of the birds were added to 

 the number and by their industry on this particular pest attracted the attention 

 of all who passed. Suffice it to say that when March came not a cocoon was 

 to be seen in those places where the branches were literally white with them 

 before, and more, this is the last we ever saw of the New Haven visitor. 



The tent-caterpillar, the gipsy moth, and tussock moth larvae all 

 belong to the class of hairy caterpillars which were formerly thought 

 to be practically immune from attacks by birds. But this idea has 

 long been disproved, and instances like the ones above quoted con- 

 vince one that hairy caterpillars are by no means distasteful to birds. 

 Two other cases may be cited in which infestations of hairy cater- 

 pillars have been subdued by birds. 



* Useful Birds, p. 70 [1907]. 



* Insect Life, III, p. 295, 1891. 



