ARCTIC THREE-TOED WOODPECKER 111 



young female is similar to the young male, but there is no distinct 

 yellow patch on the crown, only scattering yellow feathers in vary- 

 ing amounts, often few or none at all. This plumage is worn through 

 the summer and early fall; the first winter plumage, which is prac- 

 tically indistinguishable from that of the adult, is apparently not 

 fully acquired until November or December. Adults have one com- 

 plete annual molt, beginning in August. 



Food. — More than three-quarters of the food of both species of 

 three-toed woodpeckers consists of the larvae of wood-boring beetles, 

 mainly Cerambycidae and Buprestidae. Referring to the former, 

 Prof. F. E. L. Beal (1911) says: 



Stomachs containing 15 to 20 of these grubs are very common, and one held 

 34. Probably the stomach is filled several times each day, and it does not 

 seem unreasonable to assume that a bird will eat 50 of these insects every 

 24 hours for 6 months and at least 25 daily for the other half of the year. 

 At this rate one bird will annually destroy 13,675 of these destructive 

 grubs. * * * 



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 wood- 

 peckers, 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 wood- 

 pecker 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 iso- 

 lated 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 motion- 

 less, 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. 



