Introduction. 3 



Judd (75) mentions the case of fche American yellow-bellied 

 woodpecker (Sphyrapicus varius) which has developed a great fond- 

 ness for the sap of trees, in order to obtain which it pierces a 

 system of more or less symmetrically disposed holes through the 

 bark. Here the sap collects and attracts large numbers of insects 

 which are also devoured. In all probability this is an acquired 

 taste, possibly originally gained when tapping in search of insects. 

 Only profitable trees are punctured, such as apple, birch, maple, 

 and a few others. 



En the summer of 1895 nine apple trees about twelve years old, 

 apparently perfectly healthy, were attacked in the autumn by this 

 species, and during the spring and autumn of the succeeding 

 four years they resorted to them regularly. With the aid of power- 

 ful glasses two birds were watched for three hours from a distance 

 of twenty feet. During this time one seized an ant and the other 

 snapped at some insect in flight. One drank sap from the holes 

 thirty times and the other forty-one times. Later one of the birds 

 drilled two fresh holes and the other five. In November, 1900, 

 seven of the nine trees were dead, and the remaining two were 

 dying. Bark from one of the trees, when examined, was found to 

 contain eighty-four drill holes, or an average of six to the square 

 inch. Beetles of the flat-headed borer attracted by the exuding 

 sap, had oviposited in the holes, and thus the work of destruction 

 commenced by the birds was completed by these insects. 



Pycraft (99) mentions the case of the red-headed woodpecker 

 (Melanerpes erythrocepliala) "which, like its congeners, possesses a 

 protrusible tongue ostensibly for the capture of insect prey, yet 

 lives at any rate very largely, on eggs of other birds, even entering 

 hen-roosts in its quest for these delicacies ! Furthermore, and 

 perhaps as a natural sequence, it devours young birds, which are 

 killed by a blow on the head with the dagger-like bill, and through 

 the hole thus made the tongue is thrust for the purpose of sucking 

 out the brains ! It is recorded that, in Ohio, a colony of swallows, 

 represented by some dozens of nests, was so completely raided that 

 not a single young one was reared ! Occasionally, frogs were eaten, 

 perhaps by way of varying the diet. We must assume that this 

 strange departure has been but recently made, for, as yet, the 

 elaborate mechanism characteristic of the woodpecker shows no 

 signs of degeneration." 



As I have elsewhere (30) pointed out, it is with reference to, 

 comparatively speaking, a few species only that so much diversity 

 Of opinion exists. Of the majority of species it is universally agreed 

 that they are beneficial, I have, therefore, not deemed it necessary 

 for the purpose of this investigation, to destroy any of the truly 

 insectivorous species, in order to ascertain more precisely the exact 

 nature of their food. 



