NUTT ALL'S WHITE-CROWNED SPARROW 1317 



Of 32 broods of Puget Sound sparrows followed in 1936, 19, or 59 

 percent were fledged. Of S broods of Gambel's sparrows at Mountain 

 Village and 12 broods at College, 6 and 9 or 75 percent were suc- 

 cessfully fledged. This suggests the interesting possibility that the 

 northern breeding grounds may actually be safer than coastal Califor- 

 nia for raising young. The very fact that Gambers sparrows main- 

 tain their numbers by raising only one brood is also indicative of the 

 relatively lower nestling mortality. 



Fall and Winter. — An arbitrary division between fall and winter 

 does not accord either with the climate of coastal California or with 

 the phases of the annual cycle in NuttalTs sparrow. A more mean- 

 ingful designation of the time between breeding seasons would be the 

 "base level," when territorial and sexual behavior decline to a low 

 level but do not quite disappear. This period begins with the post- 

 nuptial molt in late July or early August and ends with the surge of 

 territorial and sexual activities the following January. 



The quotations that follow from Blanchard (1941) describe the 

 behavior of Nuttall's sparrows on the University of California campus 

 at Berkeley, Calif. 



My banded pairs (of adults) remained on their breeding areas through the fall 

 mid winter. Mates foraged and perched together and followed each other about, 

 uttering the ecp which serves as the location note. Both sexes sang sporadically, 

 and an occasional territorial dispute involved forceful singing and chasing. The 

 instinct to patrol the area was absent or nearly so, however, and several of the 

 pairs were joined by flocks of immatures and, rarely, by mateless adults. These 

 newcomers were treated with such complete tolerance that only the most careful 

 observation could detect a certain aloofness as well as a certain dominance in 

 the established pair. 



When the adults begin their postnuptial molt in late July and early 

 August, they become so secretive and silent that it is nearly impossible 

 to find even those banded birds whose forage routes one knows well. 

 Trilling and posturing, chasing and fighting cease. Singing usually 

 stops also, although I have one record of a loud and complete song 

 from a heavily molting male. 



Even though external signs of territorialism are suspended during 

 the molt, a definite interest in the breeding area must persist in both 

 male and female, as the following accounts show: 



On August 14, 1935, I trapped an adult male about a mile north of the campus. 

 Its tail was barely an inch long and its wings were still in the process of molting. 

 I put the bird in a darkened cage and took it by car to the campus, where I 

 banded and released it in an area at that time unoccupied by Nuttalls; the area 

 was later taken over by a pair and therefore must have been suitable. On 

 August 31 I found the male back on the spot where I had trapped it. Three 

 days later I retrapped it and found that the tail had not yet reached full length 

 and the feathers of the pileum were still in sheaths. 



