FOOD OF WOODPECKERS. 



(Picidaj.) 



INTRODUCTION. 



During the last few decades much interest has been aroused in the 

 preservation and extension of forest areas within the United States, 

 and large sums of money have been spent on our National Forests. 

 Meanwhile scientists have been studying means to combat the insect 

 enemies of forests, which in some cases have threatened the total 

 destruction of large tracts. There is probably no species of land 

 plant that has not at least one insect enemy, and the trees of the forest 

 furnish food and homes for legions. In the Fifth Report of the United 

 States Entomological Commission over 400 species of insects are 

 reported to feed on the oak, and the opinion is expressed that this 

 number is far below the total. In the same work about 80 species 

 are said to feed on the elm, 170 on the hickory, 41 on the locust, 100 

 on the maple, 105 on the birch, 186 on the willow, and 165 on the 

 pine; and in each case the list is confessedly incomplete. 



On this point Dr. Hopkins has said: 



The results of investigation lead to the conclusion that the annual loss from insect 

 work on forest trees, and their crude or finished products, amounts to at least 

 $100,000,000. 



No period in the life history of a tree is exempt from insect attack, and every part, 

 from the smallest roots to the terminal buds, leaves, flowers, and fruit, may be infested 

 by one or many species. The seed in the ground, the tender shoots of both roots and 

 stems, and the young seedling to the matured tree, may be attacked by special ene- 

 mies which injure or destroy different parts of the entire plant. In fact, living, dis- 

 eased, dead, or decaying, a tree may be the home of hundreds of species and thousands 

 of individuals of insect life. 1 



Wherever the Dendroctonus beetles have been found in standing timber, the work 

 of woodpeckers has been more or less common, and in some trees quite a large percent- 

 age of the beetle broods has been destroyed by the birds. The evidence gathered in 

 Maine a few years ago indicates quite conclusively that the birds were rendering a 

 most valuable service as a natural check to the multiplication and destructive work of 

 the eastern spruce beetle. The work of birds is common in sections where species 1 

 [Dendroctonus brevicomis], 9 [D. monticolx], and 10 [D. ponderosas], and other western 

 species are prevalent. Yet birds evidently render the greatest service where but few 

 trees are being killed, since their concentrated work may prevent an abnormal increase 

 of the beetles; but where many hundreds or thousands of trees are being killed, the 

 limited number of birds can have little or no effect. Therefore, while the birds are 

 among the foresters' valuable friends, they can not, even with the utmost protection, 

 always be relied upon to protect the forest from its enemies. 2 



1 From manuscript of lecture on Forest Insects and Their Destructive Work, by Dr. A. D. Hopkins, in 

 charge of Forest Insect Investigations, Bureau of Entomology, U. S. Dept. Agric. 



2 Hopkins, A. D., Bull. 83, Bureau of Entomology, U. S. Dept. Agric., Part I, pp. 27-28, 1909. 



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