Probably there are not many other agencies more destructive to timber than this family of beetles. Nor is timber safe even after it has been cut. Logs lying in the mill yard or forest may be ruined in a single season if these creatures are not prevented from depositing their eggs. * * * A very efficient check upon the undue increase of these insects is found in the woodpeckers, especially the two species of Picoides.
Weevils and other beetles and some ants are eaten, as well as a few other insects and spiders. Vegetable food, wild fruits, mast, and cambium amount to less than 12 percent of the food.
While with us, in southern New England, in winter, this woodpecker shows a decided preference for dead white pine trees (Pinus strobus), especially those that have been killed by fire or have been dead long enough for the bark to have partially peeled off. An isolated tree or a group of trees of this type may be visited day after day by one of these woodpeckers, during its stay, with such regularity that many an observer, who has never seen an Arctic three-toed woodpecker, may feel reasonably sure of finding one in such a place, if it has been previously seen there. Its persistent work on such a tree is well described by E. H. Forbush (1927) as follows:
This species very often begins to work on the trunk near the foot of a tree; it sounds the bark with direct blows, and then, turning its head from side to side, strikes its beak slantingly into and under the bark, and flakes it off. It often works long on the same tree and barks the whole trunk in time, only occasionally working on the branches. Thus it exposes channels of bark-beetles and the holes made by borers. When the bird remains motionless, it is well concealed against the blackened bark of the burnt trees. It seems deliberate in its movements and appears to do its work thoroughly, as it often remains five to ten minutes on the same spot and then shifts only a little distance. In early autumn, while the grubs are still at work on the tree, it lays its head against the tree, at times, turning it first to one side and then to the other as if listening.
Grinnell, Dixon, and Linsdale (1930) write of the feeding habits of this woodpecker in the Lassen Peak region:
One of these woodpeckers was watched as it moved slowly up a tree trunk. It stopped to knock off a piece of bark with a sidewise (glancing) blow of the heavy bill. This was repeated several times. Then the bird began to drill in earnest and the tapping could be heard by a person more than thirty meters distant. The blows were delivered rapidly, about two per second. Between three and five minutes were required to bore through the bark, in this instance twenty millimeters thick. Then after a few moments of probing the bill was withdrawn and was seen to hold a white larva which was quickly eaten. * * *
On one tree thirty-five centimeters in diameter an area of bark thirty by sixty centimeters was punctured completely through by twenty-two holes each leading to the tunnel of a wood-borer. * * * The holes were twelve by twelve millimeters across by twenty deep. It appeared to the observer * * * that many of the still living trees in that locality had been saved from complete destruction by the insects, by the activity of this woodpecker.
Manly Hardy wrote to Major Bendire (1895) that, in Maine, “it seems to feed entirely on such wood worms as attack spruce, pine, and other soft-wood timber that has been fire-killed. Specimens are so abundant in such places that I once shot the heads off of six in a few minutes when short of material for a stew.”
Some dead pine trees that had been regularly frequented by these woodpeckers, on the Kennard estate, were cut down; and the birds, seeing their favorite trees gone, continued to search for food on the wood piles made from these trees.
Behavior.—Most observers agree that the Arctic three-toed woodpecker is very tame and unsuspicious, working very quietly on a tree trunk for long periods, without moving about much, and allowing a close approach; perhaps, as it lives most of its life in remote northern forests, where men are scarce, it has not learned to fear human beings. Manly Hardy considered it the tamest and stupidest of the woodpeckers found in Maine. Major Bendire (1895) says: