100 BULLETIN 174, UNITED STATES NATIONAL MUSEUM 



measure 26.40 by 18.29, 25.40 by 19.50, 21.84 by 17.78, and 22.86 by 

 16.76 millimeters. 



Yoimg. — Incubation is said to last for 14 aays and to be shared 

 by both sexes. Both parents also assist in the care and feeding of 

 the young. Clarence F. Smith tells me that "the female at one nest 

 made trips about twice as frequently as the male; her visits were 

 about two minutes apart, while the visits of the male were about five 

 minutes." Grinnell, Dixon, and Linsdale (1930) write: 



On July 1, the young woodpeckers, by this time half-grown, were being fed 

 by the parents, mostly by the female. Food was brought at intervals averaging 

 fifteen minutes each. The birds foraged at distances up to a quarter of a 

 mile away from the nest. The female carried away the feces. 



On July 11 the female seemed to be coaxing the young from this nest. 

 When the young woodpeckers stuck their heads out of the cavity, the parent 

 would move away from the entrance and call, although it remained on the 

 tree trunk. When a person shook the stub two of the young birds flew out 

 and went thirty meters before coming to the ground. When placed on a tree 

 trunk the birds could move freely upward or downward. Within a few min- 

 utes one of the young birds could fly so well that it successfully evaded capture 

 by the observer. 



Plumages. — As with other woodpeckers, the young are hatched 

 naked and blind, but the juvenal plumage is acquired before the 

 young bird leaves the nest. The juvenal plumage is much like that 

 of the adult but duller, and the bill is shorter and weaker ; the con- 

 tour plumage is softer and looser; the lower parts are brownish 

 black instead of clear black, and the back is only a little darker ; the 

 white in the primaries is more restricted. In the young male, the 

 posterior half of the crown is largely "vermilion" or "salmon 

 orange" ; these reddish colors are much reduced or entirely absent in 

 the young female. Eidgway (1914) says that the feathers of the 

 hind neck and underparts are sometimes, perhaps on younger birds 

 than I have seen, "indistinctly and narrowly margined at tip with 

 grayish, and the hindneck sometimes indistinctly spotted with 

 whitish." By the middle of September this juvenal plumage, in- 

 cluding the wings and tail, has been replaced by the first winter 

 plumage, which is like that of the adult, except for somewhat less 

 white in the primaries. Adults have a complete annual molt, which 

 begins in July and is generally completed before the end of Sep- 

 tember. 



Food. — The white-headed woodpecker forages for its food mainly, 

 if not entirely, on the trunks and branches of coniferous trees, living 

 or dead. Mr. Skinner writes to me that he has seen it feeding on 

 the trunks of sequoias, sugar pines, and Douglas firs, searching most 

 diligently and thoroughly in the crevices in the bark for insects and 

 their eggs; it generally begins low down on the tree and progresses 

 upward, working pretty well up to the top of the tree before flying 



