SONGLESS BIRDS OF ORCHARD AND WOODLAND. 251 



r^TT^^Z 





Dr. Rufus H. Petit, entomologist of the Michigan Experi- 

 ment Station, says that in almost every case where cocoons 

 of this insect were concealed under flakes of bark the birds 

 had found them. " Such pierced cocoons," he says, "are the 

 common thing in our orchards, especially where they have 

 been above the snow line."' Fig. 107, 

 which is drawn from a reproduction of 

 his photograph, shoAvs the inner surface 

 of a flake of bark, the remains of a 

 cocoon attached, and the hole made by 

 the bill of the bird, 



A large part of the food of this Wood- 

 pecker, while in the orchard, consists 

 of wood-boring beetles, their larva?, 

 and various bark beetles and weevils. 

 Hardly another bird, excepting the suc- 

 ceeding species, can compete with this in destroying borers, 

 such as the round-headed apple borer, that infest fruit trees. 

 In securing these insects it never does the trees an}^ percep- 

 tible harm. In many cases it perforates the bark of apple 

 trees with small, roundish holes, less than an inch apart, 

 disposed in parallel horizontal rings. Nuttall says that these 

 holes are made for the purpose of drink- 

 ing sap from the trees. But this Avork is 

 not done for the sake of the sap, if, as 

 Wilson says, it is always performed in 

 the fall, at a time when the sap is not flow- 

 possibly the bird takes out bits of the cambium layer ; 



Pig. 107. — Cocoon of cod- 

 liu},'' moth, pierced by 

 Woodpecker. 



Pig. 108. — Apple tree 

 borer. 



ing 



Wilson believed it was delving for insects ; but whatever the 

 reason, the trees so perforated seem to be invigorated rather 

 than injured by the process, which is not the case with trees 

 similarly attacked by the true Sapsucker. The holes made 

 by the Sapsucker are different in shape, being square rather 

 than round. 



Townend Glover, formerly entomologist to the United 

 States Department of Agriculture, stated that he observed 

 the Downy making a number of small, rough-edged })erfo ra- 

 tions in the bark of an ash tree, and found that wherever the 

 bark had been thus injured the young larva of a wood-eating 



