8 WOODPECKEBS IN RELATION TO TREES. 



injuries are offset by beneficial activities of the birds will be discussed 

 later. 



HOLES MADE IN DIGGING OUT INSECTS. 



As a rule the holes made by woodpeckers when digging out insects 

 are not large, and there is every reason to believe that most of them 

 heal quickly without noticeably disfiguring the exterior of the trees. 

 They cause distortion and staining of the wood, however, as do all 

 injuries to the cambium. These defects often resemble those which 

 result from sapsucker work, but they generally occur in otherwise 

 unsound trees and are much less numerous and important. However, 

 wounds made by woodpeckers when digging out borers deeply buried 

 in the wood, by reason of their larger size, often result in bleaching 

 the wood (see PL III, fig. 6), a feature rarely observed in connection 

 with the smaller sapsucker pecks. 



Our two largest species of woodpeckers, the pileated and the 

 ivory-billed, dig great pits or furrows in living trees or split off large 

 chips. Plate III, figures 1 to 5, illustrates large wounds made by 

 pileated woodpeckers. F. M. Chapman says: "I have seen an open- 

 ing made by a pileated woodpecker in a white-pine tree 12 inches 

 long, 4 inches wide, and 8 inches deep, through perfectly sound 

 wood to reach the larvae at work in the heart of the tree." 1 These 

 large woodpeckers occasionally riddle trees which show no signs of 

 insect attack, but this is so unusual as not to warrant hostility 

 toward these fine birds, wliich are disappearing only too rapidly as 

 man encroaches upon their domain. 



All woodpeckers chip off considerable wood from dead trees and 

 branches to secure the insects therein. In spite of the good done 

 by destroying these insects, in some countries woodpeckers are held 

 in disrepute because they reduce the quantity of firewood, a view 

 not likely to be adopted in the United States. 



Indeed, the offices of woodpeckers in capturing the various wood- 

 boring insects may be likened to those of the surgeon who removes 

 diseased parts from the human body. Not only do we deem the 

 surgeon's achievement praiseworthy, but we pay him well for doing 

 it. We should maintain the same attitude toward the woodpeckers, 

 surgeons to our trees. Practically all the compensation they demand 

 is the privilege of excavating nests and sleeping shelters in trees. 



EXCAVATION OF NEST AND SHELTER CAVITIES. 



There are 24 species (and several subspecies) of woodpeckers in 

 the United States, and although most of them usually select dead 

 stubs or limbs or partly decayed trees in wliich to make their nests, 



■ Chapman, F. M., Color Key to N. A. Birds, p. 14S, 1903. 



