BIRD GUARDIANS OF THE TREES 



161 



operations that save the trees. When the leopard moth 

 was introduced into this country from Europe, it seemed 

 at first as if it were destined to destroy all our trees, but 

 as time went on, we found thtt it killed no trees except 

 ill and near the cities, where the ubiquitous English 

 Sparrow had largely driven out other birds ; in the coun- 

 try, where native birds were numerous, the ravages of 

 this moth soon were checked. In city after city its 

 wood-boring larvae killed first the smaller branches, then 

 the larger ones, and finally many trees died from its at- 

 tacks. Many ancient trees in historic parks, like Boston 

 Common and the grounds of Harvard University in Cam- 

 bridge, have been cut down or rooted out because of this 

 and other tree pests, but in the rural districts the larvae 

 of the leopard moth now do little injury, and in the woods 

 they are hard to find. Woodpeckers search for them, dig 

 into their holes, drag them out and wax fat upon such 

 sustenance. The Downy Woodpecker, the Hairy Wood- 

 pecker and the Flicker all seem possessed with a mania 

 for killing these and many other destructive wood-bor- 

 ing larvae. Better equipped than a telegraph lineman for 

 climbing; supported by a spurred tail; provided with 

 hooked claws for clinging to the bark ; hammer-headed, 

 chisel-beaked, and armed with a tremendously long, 

 strong, lance-pointed, barbed, extensile tongue, the 



PViotograph by Cordelia J. Stanwood. 



THE GREAT HORNED OWL 



This bird protects young trees by killing mice and rabbits. It 

 is a premium ratter. 



Photograph by C. W. Leister 



A FAMILY OF CHESTNUT-SIDED WARBLERS 



They feed on insects that injure woodland trees, and so perform 

 a real service for humankind. 



Woodpecker drills through the wood directly into the 

 spot where the borer lies hidden, pushes in the tip of 

 his barbed tongue, spears the victim and whips it quickly 

 into his open beak. The wonder of it all is that "Dr. 

 Peckerwood" knows just where to operate. He needs 

 no X-ray of stethoscope to determine the seat of the 

 trouble. In summer he may hear the borer working in 

 the wood, but in winter, when both insects and trees 

 are frozen, when there is no possibility of any sound 

 to guide him, the tree doctor always operates just where 

 the hibernating, motionless insects lie snugly hidden in 

 their cells. We can only surmise that he locates them 

 l)y tapping with his bill, and that his auditory nerves 

 are so sensitive to the slight differences in sound vibra- 

 tion that he knows exactly where to drive his tunnel. In 

 any case, be the enemy a few wood-boring ants collect- 

 ed at different points along their channels, or the larvae 

 of moth or beetle, the little tree-surgeon unhesitatingly 

 drills right to the spot. Cocoons hidden under the bark 

 are pierced in the same way. It is as if the eye of the 

 Woodpecker could see through bark and wood, and his 

 perseverance in digging out the enemy never fails. Even 

 the Sapsucker, execrated as he is for destroying or dis- 

 figuring certain trees, is of some service. In the year 

 1911 a bark beetle had attacked the pine forests of the 

 coast region of South Carolina and many trees were de- 

 stroyed. In the autumn large numbers of Yellow-bel- 

 lied Sapsuckers came down from their northern homes 

 and worked upon the pines attacked by these beetles. In 

 the autumn of 1912 I examined many of these trees. 

 Those that had been worked by the Sapsucker had re- 

 covered, while those that it had not drilled were dead 

 or dying. The bark of the healthy trees showed many 

 scars where the Sapsuckers had drilled through to reach 

 the beetles. 

 Insects are by no means the only enemies of the trees 



