OLD CROW 



189 



males were larger than on April 11. The testes had not reached half 

 their maximum length when these initial steps toward pairing were 

 in progress. 



Specimens taken on April 17 and 20 were stained with crowberry 

 {Empetrum) and these berries were found in the crop of one bird. 

 At this time the snow had cleared from about 40 percent of the steep 

 southeastern slope, but was continuous on the less steep and less sunny 

 areas. 



On May 10, a windy day, only one male rock ptarmigan was seen 

 at about 2,500 feet. On May 25 three collapsed ovarian follicles and 

 a brood patch in a female specimen showed that it had laid three 

 eggs, the first on May 23. Only 10 percent of her white contour 

 feathers and white primaries remained. A male companion had a 

 few speckles on the crown and one on the back replacing not more than 

 5 percent of the white feathers, and its eye comb and testes were the 

 largest noted. It is interesting that the female, although in the course 

 of an intensive program of Q,gg laying, was nevertheless marked as 

 "medium" fat, which is about as fat as ptarmigan are found. The 

 very considerable extra metabolic expenditure of laying was well 

 covered by the food supply, leaving no sign of nutritional strain to 

 suggest that the bird was under stress. This is in accordance with the 

 appearance of unhurried actions of the female rock ptarmigan during 

 the breeding season in arctic Alaska. 



On ]\Iay 26 two rock ptarmigan were seen as they stood on ex- 

 posed rocky points at an elevation of 2,500 feet, in the statuesque pose 

 which males take during nesting season. At this time and on June 9, 

 other male rock ptarmigan stood on occasional eminences high in the 

 first and second mountains at the conspicuous posts from which they 

 signal their nesting territory. The testes of specimens taken at these 

 times were smaller than the maximum size observed about May 25 

 but dark feathers had only covered the head and a few spots on the 

 neck and body. 







Measurements (Mm.) 



Plumage 











Change (%) 



Dale 



Social Behavior 



Testes 



Ova 



Male Female 



Apr. 11 



flocks disintegrating 











Apr. 17 





3x4, 3x4 

 6x8, 5x7 



1.6 





 



Apr. 20 



pairing 



6x5, 7x5 



2 



Trac 



May 22 



cf signals, 9 laying 









May 25 



cf signals, 9 laying 



11x18, 11x17 

 11x16, 9x13 



123 



1 95 



May 26 



cf signals, 9 laying 



11x18, 9x14 





1 



June 4 



cf signals, 9 incubating 



11x13, 9x12 





5 



June 9 



c? signals, 9 incubating 



11x14. 5, 10x13 

 11x13. 9x13 





5 



' Three collapsed ovarian follicles. 



