1328 U.S. NATIONAL MUSEUM BULLETIN 23 7 past 3 



On May 23, Male 1 acquired a mate. She built one nest, deserted it, and was 

 finishing another when on May 28 copulation occurred. Female 1 must have 

 begun incubation May 31, judging by the date her eggs hatched. Meanwhile 

 the neighbor on the east, Male 7, had acquired a mate. She started her nest 

 May 30. That same evening, Male 1 'attacked' her. * * * Male 7, which 

 until then had been singing regularly but not forcefully, chased Male 1, then 

 began to sing loudly from conspicious perches, patrolling his area as do males 

 during incubation. The next evening, Female 7 was attacked again by Male 1. 

 Then each time she flew, she was pursued by both males. Finally Male 7 began 

 to chase the intruder, but could not drive him back to his own area. At 9:10 p.m., 

 over one and one-half hours after the dispute had begun that evening, Male 7 

 began to patrol his territory, which now, owing to his intensified behavior, merited 

 the term in all its connotations, and incorporated into his patrol a high aerial 

 pole, from which he sang loudly. (Since there are no tall trees at Mountain 

 Village the aerial poles near the Trading Post were favorite singing perches.) 

 There followed a 'singing contest' between the two males. This lasted until 

 9:45 p.m., some time after other birds had quieted down for the night. During 

 the contest, Female 7 trilled and postured vigorously but her mate was too pre- 

 occupied to pay any attention to her. The next evening, June 1, the performance 

 was repeated, and Male 1 flew at Pair 7 whenever they attempted copulation, 

 preventing the mating not only psychologically but also physically, at least as 

 long as I watched. By the next day the situation had returned to normal: each 

 male sang from his respective territory. Pair 7 must have succeeded in copulat- 

 ing, for the female finished her nest June 1, laid her first egg June 3, and all eggs 

 hatched June 19. 



Nesting. — At Mountain Village I first saw nest building 11 days 

 after the average date for arrival of the males and only 3 days after 

 the average day date for arrival of the females. The intervals be- 

 tween arrival and nest building at College are closely comparable: I 

 first saw a female building on May 20, 12 days after the average date of 

 arrival for males and 3 days after average arrival date of the females. 

 At both localities the interval between arrival of the female and the 

 start of nest building lasted only 2 or 3 days, as contrasted with the 

 corresponding interval of 1 to 2 weeks for Puget Sound sparrows at 

 Friday Harbor. The time spent in building is also shorter. At 

 Mountain Village four GambeFs sparrow females spent 2 to 4 days in 

 building. At College one female was first seen building on May 21, 

 and again on May 24. She laid her first egg May 26. It will be 

 remembered that both Nuttall's and Puget Sound sparrows spend 

 from 7 to 9 days building the first nest of the season. 



Eggs.— Gambel's sparrows lay the first egg from to 3 days after 

 the nest is finished. I have two records of females that worked on 

 their nests the same day they laid the first egg of their clutch. For 

 seven females seen while building, the average interval between the 

 date they were last seen building and the date they laid their first 

 egg was 1 day. The corresponding interval for nuttalli is 3.6 days, 

 for 2>ugetensis, 2.6 days. 



