SONGLESS BIRDS OF ORCHARD AND WOODLAND. 251 
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, shows 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 larve, sie. 107.—cocoonof cod- 
and various bark beetles and weevils. ling moth, pierced by 
Hardly another bird, excepting the suc- waryere 
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 any 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 work is 
not done for the sake of the sap, if, as 
Fig. 108.—Apple tree Wilson says, it is always performed in 
a the fall, at a time when the sap is not flow- 
ing; possibly the bird takes out bits of the cambium layer ; 
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 entothologist to the United 
States Department of Agriculture, stated that he observed 
the Downy making a number of small, rough-edged perfora- 
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 
