184 BULLETIN 16 2, UNITED STATES NATIONAL MUSEUM 



chiefly with narrow, dusky terminal bands, and often tipped, on the chin 

 especially, with white. It should be observed that parti-colored feathers 

 basally or terminally white, may be assumed at this moult on the internal bor- 

 ders of the sternal baud, just as in juvenal dress, the abdominal wedge, flanks, 

 legs, and feet, retaining as a rule the white feathers of the winter plumage. 

 The white remiges and their coverts are always retained and often much of 

 the rest of the wing plumage, the median rows of coverts being the ones re- 

 newed if any are. The tail-coverts may be renewed, but the fourteen black 

 rectrices remain. 



Dwight says of the next molt : 



Even before the nuptial dress is fully acquired the postnuptial moult sets 

 in, beginning a little prior to the postjuvenal and resulting in an intermediate 

 plumage partly white and partly reddish brown which may hardly be told 

 from that of young birds at the same season. It should be observed that 

 the moult of the remiges now includes the two distal primaries which are re- 

 tained in young birds. Adults, however, seem to be somewhat grayer with 

 finer mottling or vermiculation, the throat being of a deeper red-brown with 

 less barring than that of young birds. Practically young and old, both males 

 and females, are all indistinguishable except by inconstant differences when 

 clothed by the preliminary winter dress, but their age and sex may usually 

 be told by the left over tell-tale feathers of an earlier plumage. 



A supplementary molt early in fall, September and October in 

 Alaska, completes the change into adult winter plumage. Females 

 are indistinguishable from first winter birds, the feathers of the 

 crown being basally gray, whereas in the adult male these are basally 

 black. Winter adults in high plumage often have a decidedly rosy 

 tint, which soon fades in the dry skin. 



Food. — During summer ptarmigan feed on the tender leaves and 

 flower buds of the willows, birches, and alders, with a fair per- 

 centage of berries, such as mountain cranberry, crowberry, blue- 

 berries, arbutus, and kinnikinnick. They also eat what insects they 

 can find. Turner (1886) writes: 



During the winter these birds subsist on the past year's twigs of the willow 

 and alder or other bushes. I have cut open the crops of many of these winter- 

 killed birds and found them to contain only pieces of twigs about one-third 

 of an inch long, or just about the width of the gape of the posterior, horny 

 part of the bill, as though this has been the means of measurement in cutting 

 them off. The flesh at this time is dry and of a peculiar taste. In the spring 

 the Ptarmigans congregate in great numbers on the willow-bushes and eat 

 the tender, swelling buds. The flesh then acquires a bitter, but not unpleasant, 

 taste. As open weather advances they find berries that have remained frozen 

 the entire winter, and tender grass shoots, and later, insects. The young are 

 insectivorous to a great degree in their youngest days. They consume great 

 numbers of spiders that are to be found on the warm hillsides. 



Dixon (1927) sent the stomach of a 5-day-old chick to Washington 

 for examination; it contained 17 yellow caterpillars, 1 spider, 15 



