NUTT ALL'S WHITE-CROWNED SPARROW 1301 



In the three races I have seen, nest building is solely by the female. 

 The following description for Nuttall's sparrow applies to Puget 

 Sound and GambeFs sparrows as well. Such racial differences as 

 exist involve the length of time the female takes to finish the nest and 

 the interval between fledging the first brood and starting the second 

 nest. 



In Nuttall's sparrow the first hints of nesting are the male's "sseep" 

 note, which may precede nest building by as much as 8 days, and the 

 interest the female shows in nest material. For a week before she 

 begins to build she may pick up straws and then drop them. During 

 this period she may also utter the characteristic "eep" location note 

 which she subsequently uses during nest building and incubation. 

 She may protest if one approaches the future site of the nest. Several 

 days or a week after these behavior elements have appeared sep- 

 arately, they merge and intensify into coordinated activity, and she 

 begins continuous work on the nest. Her mate perches nearby and 

 utters the "ssseep call note, which may stimulate her to build. The 

 details of a single morning's work of one Nuttall's sparrow female are 

 as follows: 



On March 11, which was the second or third day she had worked on 

 the nest, I watched her from 8:00 to 11:30 a.m. At 8:15 she carried 

 material to the nest, and from then until 11:30 built almost continu- 

 ously, making 135 trips with material, stopping only three times and 

 then only for a moment to feed. Almost all the material was gathered 

 within a few yards of the nest; it consisted of dead twigs and leaves, 

 strands of dry grass, pine needles, small green plants, and fresh grass 

 stems. Dead leaves and dry grass were brought most often. She 

 brought only three twigs, all within the first hour. After every few 

 trips she could be heard fluttering in the nest, probably molding the 

 cup. This female spent parts of the next three days in building, but 

 never worked as continuously as on March 11. By March 15 the 

 nest appeared complete. 



Nest-building in Nuttall's sparrow begins a few days before copu- 

 lation, when trilling and posturing are reaching the climax. The 

 number of days spent in building the first nest of the season was from 

 7 to 8 or 9 for the five nests found just as the female was starting work. 

 Three were worked on during parts of 7 days, one during parts of 8 

 days, and one 8 or 9 days. If a clutch or a brood of nestlings is 

 destroyed, the female starts a new nest within a few days and may 

 complete it in 5 or 6 days. 



Eggs. — The color of the eggs has been described variously as "pale 

 greenish-blue, spotted and splashed with liver-brown" (Davie, 1883) 

 or "a handsome light green or bluish-green shade, * * * heavily 

 dotted, spotted, blotched or clouded with reddish-brown" (Dawson, 



