120 U. S. NATIONAL MUSEUM BULLETIN 217 



Alaska. The opening of the birch leaves was about two weeks later 

 than usual at Fairbanks. On the Kobuk Kiver at Kobuk Village the 

 snow was still deep on May 25 and the streams, just beginning to flow, 

 had yet to break open the ice on the river. Here the white-crowned 

 sparrows were in small groups, but a few appeared to be paired. 

 Seventy miles north, in the upper ISToatak Valley I saw these sparrows 

 in small groups, with some apparent pairs. 



When we reached Anaktuvuk several days later, the first arrivals 

 of white-crowned sparrows had been reported on May 20, three or 

 four days later than the mid-date for the preceding 3 years. If this 

 small delay in observation represented delayed migration, it was not 

 apparent in the behavior of the birds, which took territory, sang and 

 nested according to their regular calendar schedule. 



Barbara Oakeson (1954) found that male white-crowned sparrows 

 became numerous at Mountain Village, Alaska (on the lower Yukon 

 River, lat. 62°07' N.) , before the females did. Of the specimens taken 

 at Anaktuvuk in May there were 20 males and 5 females. Eleven of 

 the males in which the greatest length of testes was measured ranged 

 in this character between 6 and 9 mm. Six males measured in early 

 June ranged in length of testes from 8 to 10 mm. It appears that at 

 Anaktuvuk, as Mrs. Oakeson found at Mountain Village, male white- 

 crowned sparrows arrived on the breeding grounds in numbers before 

 the females. One female was taken at Mountain Village earlier than 

 any male, so the precedence of males is not exclusive but rather a 

 majority. Further, in the arriving males at Anaktuvuk the testes 

 have not reached full size. The development of eggs also had not 

 progressed beyond 5 mm. diameter in the latest female taken during 

 May, and it is apparent that both male and female birds complete 

 their physiological preparation for breeding after arrival on the nest- 

 ing grounds. 



In connection with these comments upon gonadal development it is 

 important to note that Mrs. Oakeson studied only white-crowned 

 sparrows which showed by their behavior that they had settled at 

 Mountain Village to nest. The locality is in the peninsula of the 

 Yukon Delta only 40 miles from the coast of Bering Sea. At Anak- 

 tuvuk we have not so carefully distinguished that the white-crowned 

 sparrows examined had settled for nesting. But these sparrows are 

 rare on the arctic coast of Alaska and there was no noticeable con- 

 centration of incoming birds in numbers nor were flocks larger than 

 small groups observed. Since only about 100 miles of possible nesting 

 territory for white-crowned sparrows exists north of Anaktuvuk the 

 population examined is at or close to its breeding ground and in this 

 respect comparable to the birds studied by Mrs. Oakeson. 



In early June, many Gambel's sparrows were singing, having al- 



