238 



THE GYPSY MOTH. 



could see her go and come for at least a thousand yards. 

 She flew about twenty-five yards from the earth, going 

 straight from the locality in which her nest was situated to 

 the locality from which she procured the food. Other small 

 birds have been known to fly an equal distance to secure 

 food for their young. 



The distribution of caterpillars by birds goes to prove the 

 rule that nature does not usually work for the extermination 

 of species. AYhile the birds are very useful as assistants in 

 the work of extermination by destroying the gypsy moths, 

 they hinder the work to some extent by distributing the 

 laryee and the female moths. 



Ko appreciable distribution of caterpillars by birds will 

 occur, however, except when caterpillars are present in large 

 numbers, for then only will birds go to a distance to secure 

 caterpillars as food for their young. Probably no other 

 form of dissemination of caterpillars by birds will materially 

 extend the moth's distribution even under the most favorable 

 conditions. Wherever the caterpillars are present in large 

 numbers in a settled country, they will be carried much far- 

 ther and scattered abroad more widely by man and domestic 

 animals than by birds. In woodlands remote from civiliza- 

 tion, birds might be the principal factor in diffusing the 

 moth to a short distance from badly infested spots, but the 

 distribution of the moth in such places is not of so much 

 moment as in cultivated and settled regions. If the moth 

 were allowed to increase and spread over the whole State, 

 we may infer that all possible distribution by birds would 

 be of little importance as compared with the good they 

 would do in checking the increase of the moth. 



In towns where the moths are few and where most of them 

 have been already destroyed, and especially in small isolated 

 colonies, birds are very useful allies in the work of extermi- 

 nation. In such localities they take the caterpillars only 

 when they come in their way, and rarely carry them to their 

 young unless the nests are quite near the infested spot. 

 Undoubtedly in many such cases birds have contributed as 

 much toward the extermination of the moth as have the men 

 employed in the work of extermination. Where the cater- 

 pillars are few, therefore, birds render efficient assistance in 



