196 THE AMERICAN MUSEUM JOURNAL 
observation. Indeed a ther- 
mometer would doubtless 
have proved the necessity 
of the bird’s presence if its 
eggs were not to be cooked 
by the noon-day rays of a 
July sun. 
Passing by the groups ar- 
ranged along the side of the 
hall, each one of which has a 
biologic story of its own, we 
journey from the Atlantic to 
the Pacific and find the case 
of the skimmer practically 
repeated by the black-necked 
stilt in the San Joaquin Val- 
ley group. Here again is a 
conspicuous black and white 
parent, while the downy 
young wear an admirably 
disguising costume, which 
persists even to the plumage 
of flight worn by the half- 
grown stilt which is squat- 
ting in the vegetation at the 
water side. Note also in this 
group how effectively the 
color of the downy black 
tern in the foreground blends 

WHITE-TAILED PTARMIGAN IN SUMMER PLUMAGE 
its wearer with the details of 
A portion of the Arctic-Alpine group. The 
female ptarmigan is protectively colored; she 
will allow herself to be touched before deserting 
the nest contains a further illustra- 
its nest. 
This San Joaquin group 
tion of protective coloration 
in the cinnamon teal and ruddy duck. When molting, these birds, in 
common with grebes, murres and other diving birds, lose all their wing 
quills simultaneously and are consequently flightless until new ones are 
acquired. Apparently, therefore, to aid in their concealment during this 
comparatively helpless period, the males shed the more striking portions 
of their distinctive plumage which is replaced by a dull, neutral-tinted 
plumage like that of the female. This is worn only until they reacquire 
