182 BULLETIN 16 2, UNITED STATES NATIONAL MUSEUM 



" garnet brown," while the deeper colors are " warm blackish brown " and 

 "blackish brown (1)." 



The measurements of 250 eggs, in the United States National Mu- 

 seum, average 43 by 31 millimeters; the eggs showing the four ex- 

 tremes measure 48 by 31.5, 46.5 by 34, 39 by 30, and 39.5 by 28 

 millimeters. 



Young. — Mr. Conover says in his notes : 



Newly hatched young were first found on June 22. The incubation period 

 seems to last about 22 days. A nest found on June 2 with 11 eggs had 12 on 

 June 3, and on being visited on June 25, it was found to be empty. The chicks 

 are very precocious. One day a hen was flushed from a nest containing two 

 eggs and eight youngsters still damp. Hardly had she left when every downy 

 chick scrambled weakly from the nest and attempted to hide in the grass. The 

 minute they were replaced, out they would go again, until finally they became 

 tired out and stayed in the nest. Toward the end of June broods were con- 

 stantly encountered about the tundra. Both parents were always with them 

 and the cock was especially combative, although discretion always got the 

 better part of valor. The young after running a few feet would suddenly dis- 

 appear, whereupon the hen would join the male in threats and attempt to lead 

 one off. It was amusing to imitate the peeping of a chick and watch the cock 

 go into a frenzy, ruffling himself up, making short dashes here and there, and 

 in unmistakable language telling you just what he was going to do if you didn't 

 get away from his children. After a few minutes of this, both birds would be 

 worn out and would retire a short way to watch for your next move. By July 

 22 the young were about a third grown and had begun to shed their first brown 

 primaries and grow their new white ones. The adults were then in the midst of 

 shedding their toenails. 



Dixon (1927) noticed that the family party traveled as follows: 



First came two or three chicks in the thick grass, then the mother surrounded 

 by the other chicks ; the cock sometimes led and at other times brought up the 

 rear. I timed them and found that they covered a lineal distance of 45 feet in 

 five minutes. Following this there came a period of rest of five minutes, during 

 which the mother hovered her brood of young. We never saw the cock hover 

 the young; but when one of the chicks became entangled in a network of twigs 

 he was right there and helped it get free. By noon the ptarmigan family had 

 wandered out in the low bushes 100 yards from where they had hatched. The 

 chicks were now nearly 24 hours old, and all of them were strong and lusty, 

 each able to run about with agility and to secure food for itself. At Copper 

 Mountain, about 4 o'clock in the afternoon of July 12, a family of Willow 

 Ptarmigan came feeding along through the dwarf willows near camp. There 

 were six young about the size of quail. The cock kept a lookout for enemies 

 from elevated positions while the hen herded the young along through the 

 willows. The hen kept up a running conversation with the young as did also 

 the cock. This liaison note was a loud ke-onck, repeated at intervals of from 

 five to ten seconds. The cock's call was somewhat coarser than that of the hen. 

 I had difficulty in hearing the thin peeping of the chicks at a distance of fifty 

 feet, but it served to keep them together. The young were very active, jumping 

 up into the willows and catching insects over a foot off the ground. 



Plumages. — In natal down the young willow ptarmigan has a large 

 patch of " burnt sienna," bordered with black, on the center of the 



