132 BULLETIN 174, UNITED STATES NATIONAL MUSEUM 



eral, alarm calls of the parents had little if any effect upon the 

 squeaking of the nestling, though at one time, July 7, the squeaking 

 seemed to cease for a short interval when the parent gave the alarm 

 notes. For the most part the series of squeaky notes is continuous. 

 It was by hearing these sounds that this nest was discovered." 



Plum,ages. — [Author's note: The young sapsucker is hatched 

 naked, as is the case with other woodpeckers, but the juvenal plumage 

 is acquired before the young bird leaves the nest. The sexes are 

 alike in the juvenal plumage. A young bird, not fully grown and 

 l)robably not long out of the nest, taken June 25, has the black crown 

 largely concealed by the long brownish tips of the feathers, "ochra- 

 ceous-tawny" to "buckthorn brown"; each of the black feathers of 

 the back has a large terminal spot of grayish white, or yellowish white, 

 producing a boldly spotted pattern; the nape and sides of the neck 

 have smaller spots of the same color; the wings and tail are as in 

 the adult fall plumage ; the chin and upper throat are dull white or 

 pale buffy brownish ; the lower throat and chest are pale brownish, 

 broken by crescentic bars of dusky ; and the center of the breast and 

 the abdomen are pale yellow or yellowish white. Changes soon begin 

 to take place, at irregular intervals, during which the sexes begin 

 to differentiate. Young males may begin to show traces of red in the 

 throat patch as early as July; and in August some may have the 

 crown largely crimson ; the black patch on the chest does not usually 

 appear until much of the red has been assumed, but some birds show 

 considerable of both red and black before the end of August. Other 

 young males may not acquire much red before the end of September. 

 Progress toward maturity continues all through fall, winter, and 

 early spring by protracted partial molts; probably most individuals 

 acquire the fully adult plumage by early spring, but I have seen 

 birds that had not fully completed this prenuptial molt by the end 

 of April. 



Young females follow the same sequence of molts but are some- 

 what later in developing the red crown, which apparently is not 

 acquired until October or later. The adult body plumage of both 

 sexes is acquired during winter and early spring. Adults have a 

 partial prenuptial molt about the head and throat early in spring 

 and a complete molt late in summer and fall. In fresh fall plumage, 

 the lighter markings are more or less suffused with yellowish or 

 buffy tints, and the belly is deeper yellow.] 



Food. — ^W. L. McAtee (1911) learned by stomach examinations 

 that the yellow-bellied sapsucker consumed cambium and bast 

 averaging 16.71 percent of its diet. He continues : 



It must be noted also that cambium is a very delicate, perishable material, 

 at certain times no more than a jelly, and thus never receives a percentage 

 valuation in examinations of long-preserved stomachs corresponding to its bulk 



