206 
BIRDS OF NEW MEXICO 
was very amusing. They stayed exactly as they were at her first note 
and held the pose for it seemed a minute until the mother gave a satis¬ 
fied little cluck; then they went on with their feeding, none of them 
either before or after the alarm paying the slightest attention to me, 
seeming to depend utterly on the mother’s watchfulness” (1927, p. 145). 
Testimony as to the efficacy of their protective coloration is given by 
Mr. W. C. Bradbury and his party of would-be photographers who have 
had the birds vanish almost before their eyes (1915, pp. 216-218), and 
by remarkable photographs of almost invisible brooding birds on the 
nest. As the birds live wholly on mountain slopes exposed to hawks 
and eagles their lives depend on this “obliterative” coloration developed 
in conjunction with slow movements. In spring and fall, as Abbott 
Thayer states, “the birds pass through a long intermediate stage, when 
they are curiously and ever-varyingly pied with white and brown 
or gray . . . the extraordinary slowness of the two seasonal color- 
changes, “covering the periods of snow patched ground between the 
snows of winter and the bare ground of summer” (1909, chap. 7). On 
September 20, 1921, in northwestern Alaska when Mr. Alfred Bailey 
found just a faint trace of snow on the ground and the Ptarmigan which 
were changing to the white winter dress were very conspicuous on the 
brown tundra, they would “usually alight in patches of ‘Alaska cotton/ 
a grass with cotton-like tufts which effectually concealed them” (1926, 
p. 121). This raises an interesting question—a bird’s sense of its own 
protective coloration as a biproduct of natural selection. How neces¬ 
sary is it to make protective coloration protect, to save the life of the 
bird? 
When studying the Alaska Willow Ptarmigan, Mr. Joseph Dixon had 
many interesting experiences. The cock, which seems to be an excep¬ 
tion not only to other ptarmigans but to most cocks of the grouse family, 
we are told shows a strong attachment for the young, assisting in 
taking care of them and displaying as great solicitude for their 
safety as the female. A brooding female discovered when off the 
nest, “sneaked along, with body, head and tail all low to the ground. 
. . . The behavior of the male was entirely different. He strutted 
about with tail sticking out stiffly behind. The head was carried erect 
and his neck was extended. The vivid coral red comb over each eye 
was carried erect and was conspicuous to a distance of about fifty feet. 
He kept hiding by running behind trees, but when a little way off he 
would mount a tundra tussock or rock and give his coarse warning 
cackle.” His combs, held erect in alarm, when he was at rest were 
relaxed and not nearly so noticeable. 
When coming upon an old hen and her brood, Mr. Dixon says, “I 
rushed after the young, trying to catch one. Just as I was about to 
grab a chick, a willow bush in front of me exploded and the cock ptar- 
