388 BULLETIN 191, UNITED STATES NATIONAL MUSEUM 



lose all fear of the human intruder in their anxiety to defend their 

 young, and Dawson (1923) says: "Not infrequently, if the young are 

 kindly treated, the parent bird will venture upon the hand or shoulder to 

 pursue its necessary oflfices." 



Plumages. — I have seen no very young chickadees of this species. 

 In the Juvenal plumage, which is mainly acquired by the time the 

 young bird leaves the nest, except that the wings and tail are not fully 

 grown, the color pattern is the same as in the adult ; the chestnut of the 

 back, however, is duller, and that of the sides and flanks is duller and 

 paler; the plumage is also softer and less blended. A partial post- 

 juvenal molt, involving the contour plumage and the lesser wing 

 coverts, but not the rest of the wings or the tail, takes place in August; 

 by the first week in September the young bird has acquired a first winter 

 plumage that is practically indistinguishable from that of the adult. 

 Adults have one complete postnuptial molt in August and September. 



The birds show some signs of wear and fading before summer, but 

 assume the darker and more richly colored plumage in fall. 



Food. — Prof. F. E. L. Beal (1907) studied the contents of 57 stomachs 

 of the c.hestnut-backed chickadees, taken in every month except March, 

 April, and May, and found the food to consist of nearly 65 percent of 

 animal matter and 35 of vegetable. Caterpillars constituted 18 percent 

 of the animal food, taken in nearly every month, even in December and 

 January ; the largest amount, 53 percent, was taken in August. Hemip- 

 tera, leafhoppers, treehoppers, and olive and other scales were the most 

 important item of food, amounting to about 25 percent. "Wasps were 

 eaten to the extent of 13 percent of the food, but no ants were found. 

 Beetles amount to less than 2 percent of the food, but nearly all are 

 noxious; weevils appeared in one stomach." No trace of flies or grass- 

 hoppers was found. Spiders amounted to 7 percent for the year but 

 amounted to nearly 16 percent in August. 



"The vegetable portion of the food consists of fruit pulp 8 percent, 

 seeds nearly 20 percent, and miscellaneous matter 7 percent. Fruit 

 pulp was found only in a few stomachs taken in fall and winter and 

 was probably waste fruit. The seeds eaten were mostly those of conif- 

 erous trees." 



Dr. Dickey (MS.) writes: "When they have wearied themselves in 

 taking food from the trunks of trees, they will pass to huge crumbling 

 logs, peck at green moss pads for certain items, and flit into and glean 

 the tangled branches of such shrubs as salal, elderberry, dwarf blue- 

 berry, depauperized paper birch, alders, dogwood, etc.. By mid-March, 

 hordes of small winged gnats arise from the newly unfolding buds of 



