214 BULLETIN 16 2, UNITED STATES NATIONAL MUSEUM 



water in a pond; it would be interesting to know how the mother 

 transported her j^oung to the shore. 



Eggs. — The eggs are indistinguishable from those of the rock 

 ptarmigan. The measurements of 51 eggs average 41.9 by 30 milli- 

 meters; the eggs showing the four extremes measure 44.5 by 29.5, 

 44 by 32, 39 by 30, and 40 by 29 millimeters. 



Food.— A. L. V. Manniche (1910) says: 



Their principal food consisted of buds and short bits of stalks of Salix 

 arctica. According to Dr. Lindhard's analyses stomachs of Ptarmigans shot 

 at this season also contained leaves of Dryas ootopetala and crowns of leaves 

 of Saxifraga oppositifolia. 



In stomachs of shot young ones I found remnants of plants as well as of 

 insects. The old birds in summer also partly feed on insects. 



Behavior. — The same observer writes: 



In fine weather these hardy birds did not seem inconvenienced by the 

 temperature frequently as low as some 40° below zero. But it was hard for 

 the ptarmigans to support their lives during severe snow-storms and when 

 the earth was covered by thick, evenly lying crusted snow. 



At sunset they flew to the rocks and remained there over night. In the 

 heavy snowmasses on the leeside of the rock they digged holes some 20 centi- 

 meters deep, just large enough for the body of the birds, and here they spent 

 their nights apparently without ever altering position judging from the 

 manner in which the excrements were deposited. When several ptarmigans 

 had spent a night in company, their holes were always placed within a rather 

 narrow circumference sometimes nearer and sometimes at a longer distance, 

 but never quite close to each other. The ptarmigans would also often spend 

 their nights in narrow ravines in the rocks filled up with snow. 



Sometimes I found my old foot-prints taken possession of by the ptarmigans 

 as night-quarters. They were by night not seldom frightened out of their 

 holes of polar foxes and erimines. which could be easily seen on new fallen 

 snow. I found, however, in no case, signs that ptarmigans were caught in 

 this way. 



When a female ptarmigan was going to fly up, she would raise the feathers 

 on the back of her head to a pointed crest and lay the tips of her wings on 

 the upper rump uttering a suffocated clucking, that could best be compared 

 with the call of FrlvgiUa montifringilla ; at the same time she would execute 

 some courtesying movements with her head and the forepart of her body. 



Just after a heavy snow-storm, that, covered all the earth evenly with snow, 

 the ptarmigans would prove extremely shy. For a few moments at a time 

 they would settle on summits of rocks or stones, that reach over the snow, and 

 then, by a rapid soundless flight, disappear around corners of rocks through 

 deep ravines or out over extensive plains. When the ptarmigans after some 

 hours had found places with food, they would again become tranquil. 



Winter. — It seems to be well established that this and other true 

 rock ptarmigan are migratory. Mr. Manniche (1910) says: 



In the absolutely dark season ptarmigans or foot-prints of them were nowhere 

 found in spite of numerous researches on different places, and there can be 

 no doubt, that tins species for some three months leaves this part of North- 

 East Greenland. 



