160 



AMERICAN I'ORESTRV 



Photograph by Cordelia J. Stanwood. 



LITTLE TREE DOCTORS 



Hairy woodpeckers just from the nest. They seem possessed 

 with a mania for destroying forest insects and larvae and are 

 indispensable to the scheme of forest protection. 



large enough to attract our notice. Then come the breed- 

 ing birds, searching the trees all summer for food for 

 their insatiable young, and with autumn comes another 

 imtnense migration of hungry birds, penetrating all the 

 forests and searching for what the summer birds have 

 left. 



Thus is exerted the regular repressive influence of 

 birds upon the enemies of trees, and if there are birds 

 enough, and all the other forces of repression work in 

 harmony, insect pests do no appreciable injury, the 

 trees flourish and the forest remains in full leafage and 

 fruitage. 



Too well, however, we know that this is not ever\'- 

 vvhere and always the case. There are pests introduced 

 from foreign shores that seem to be invincible. There 

 are local outbreaks of native pests that the birds seem 

 ])owerless ot check, and sometimes these irruptions as- 

 sume alarming proportions. Such infestations, how- 

 ever, may often be traced to a prior scarcity of birds, 

 and when such invasions occur, they are almost cer- 

 tain to be followed by an increase of birds drawn from 

 the surrounding country. Such augmentation of the 

 feathered tribes often has been known to check a great 

 invasion of insects, for it is one of the functions of birds 

 to jT;athcr swiftly from far and near, like winged police- 

 men of the air, to quell such disturbances. 



How a scarcity of birds may result in the destruction 



of foirests is told by Wilson Flagg in the annual report 

 of the Massachusetts State Board of Agriculture for 

 1865. In 1798 the forests in Saxony and Brandenburg 

 were attacked by lepidopterous borers that killed the 

 trees. The calamity became so general that expert for- 

 esters and naturalists were employed by the regency to 

 inquire into its cause. They reported that the unusual 

 and extraordinary increase of these insects was due to the 

 absence from the forests for several years of certain 

 Woodpeckers and Titmouses. 



An increase of birds is followed always by a decrease 

 of insects on which they feed. 



Mr. B. A. Arnold told me that in the summer of 1913 

 a spruce moth became so abundant on parts of Mt. Desert 

 Island that the people began to fear the total destruction 

 of the spruce woods. He had noticed that numerous red 

 squirrels were destroying eggs and young birds, and 

 therefoire on his own estate, situated on a peninsula, 

 almost an island, he had shot all the squirrels. As a re- 

 sult of this the birds on his place increased largely. In 

 a short time the trees were cleared of both caterpillars 

 and moths by the birds, which fed them to their young ; 

 while on the mainland, where squirrels were still numer- 

 ous and birds were few, the devastation of the trees con- 

 tinued. 



Woodpeckers are indispensable in the forest. Old "Mr. 

 Peckerwood" is a tree doctor. He performs surgical 



Photograph by Cordelia J. Stanwood. 



YOUNG FLICKER EXPLORING ITS FIRST TREE 



It will be relentless in its search for the enemy and merciless 

 when the enemy is found. 



