BIRDS AS CONSERVATORS OF THE FOREST. 24 1 



a remarkably constant element of the food of most species of woodpeckers, which 

 from their peculiar physical conformation are able to secure them though concealed 

 in the solid wood, and in this way protected from the attacks of other birds. 

 Stomach examinations show that with some species very few days pass when they do 

 not get at least one meal of this kind of food. Besides these larvae many adult 

 beetles of the same families are also taken, as well as others which prey upon trees, 

 such as the engravers (Scolytidae) and some of the leaf-eaters (Chrysomelidae). 



The ants are another family of insects that prey upon trees and do great dam- 

 age. When a tree has been damaged by woodboring larvae, and these have been 

 destroyed by woodpeckers, a colony of ants will generally occupy the vacant burrow, 

 which they at once enlarge and extend till in course of time, as the colony increases, 

 the whole trunk is riddled. Upon these the woodpeckers bring to bear the same 

 tactics that were used in dislodging the woodboring grubs. The ants are dug out 

 and devoured, and examination of the stomachs of many individuals of several 

 species of these birds shows that they constitute a very considerable element of 

 their food. Many stomachs contained nothing else, and, like the woodboring grubs, 

 they form an almost daily article of diet. They are eaten in all stages — eggs, 

 larvae, pupae, and adults, and all of these forms may sometimes be found in a 

 single stomach. 



Besides the direct injury which the ants cause to the trunks of trees, they are 

 indirectly responsible for a good deal of mischief to the foliage done by the plant- 

 lice (Aphides), which they distribute and protect. The relation of the ants to the 

 plant-lice is quite like that of a dairyman to his cows. In fact, a French writer 

 upon popular natural history has spoken of the ant as "the little black milkmaid, 

 who pastures her green cows in the meadow of a rose leaf." This is a graphic, if 

 somewhat fanciful, picture of the relations of ants and plant-lice, but unfortunately 

 the black milkmaid does not limit her pasture to the rose leaf meadows. There are 

 comparatively few plants which do not suffer to some extent from the ravages of 

 plant-lice, and many forest trees seem to be especially subject to their attacks. 

 Ants protect these lice from harm, and when the plant on which they are feeding is 

 exhausted, carry them to fresh pastures and in some cases actually build shelters 

 over them. Besides destroying the ants the woodpeckers eat many of the plant-lice. 



Bark-lice, or scales (Coccidae), are also eaten quite extensively by the smaller 

 species of woodpeckers, and as these creatures are very difficult to distinguish after 

 they have been partially digested, it is probable that more of them are really 

 taken than are credited to the birds. Many insects' eggs are eaten by the smaller 

 woodpeckers, more especially those of the tent caterpillars (Malacosoma), which are 

 found during the fall and winter months. 

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