1428 U.S. NATIONAL MUSEUM BULLETIN 237 part 3 



at ten inches, and several were dropped on the way. In a heroic effort to main- 

 tain a proper balance with a coveted twig while striving to reach its destination, 

 the bird's body was almost perpendicular, its attitude and rapid wing movement 

 reminding one of a hummingbird at a long-necked flower. 



The continual song of the male, from his favorite perch near the nest site, and 

 the fact that the sitting bird, while feeding nearby, is not replaced by its mate, 

 leads to the belief that the female alone attends to the duties of nest construction 

 and incubation. Sometimes, while near the nest, the male breaks into song, not 

 only when standing on the ground but when he is scratching or hopping about in 

 the brush as well. 



In spite of the startling amount of general destruction of eggs, young and nests 

 of birds, presumably by chipmunks, predatory birds, snakes, etc., prevalent in 

 the Lake Tahoe region, no nests of this fox sparrow were molested before the eggs 

 were hatched. This was probably due to the facts (established by careful obser- 

 vation) that incubation commences with the laying of the first egg, and that the 

 sitting bird never goes far from the nest. 



Wright M. Pierce (1921) says that eight nests of stephensi he found 

 in the San Bernardino Mountains 



are all very similar * * *. In size they average, outside depth, 4.5 inches; inside 

 depth, 1.75; outside diameter, 6; inside, 3. Nests are composed of coarse sticks and 

 pine needles, with some fine twigs and weed bark, lined with grass, weed bark, 

 and, at times, mammal fur. The nests on the ground were usually less well made, 

 with more pine needles and leaves, rather than coarse sticks. 



* * * The birds nest, so far as we have found, either on the ground or up in 

 buckthorn bushes. I believe they build more often on the ground, where the 

 nests are very hard to locate, especially, if they are placed under a thick mat of 

 tangled buckthorn. At times they seem to choose the most open sort of location. 

 They just seem to be where they are! My experience indicates that the birds 

 are very close sitters, and three seems to be the usual clutch of eggs. 



Bendire (1889) writes that in schistacea: "Incubation, as nearly as 

 I was able to determine, lasts from twelve to fourteen days; both 

 sexes assist." Apparently nobody has ever measured the incubation 

 period in this species accurately, and considerable disagreement is 

 manifest in the literature on the roles the two parents play in various 

 aspects of the reproductive cycle. It seems unlikely that such basic 

 and ingrained behavior traits should vary between populations of the 

 same species. In the absence of a definitive study, it appears most 

 probable that nest building and incubation are almost entirely if not 

 entirely by the female alone, and that the male remains close by and 

 helps his mate feed the young after they hatch. 



Young. — Linsdale (in Grinnell, Dixon, and Linsdale, 1930) made 

 the following observations at a nest of megarhyncha which, when 

 found on June 16, 



* * * contained two young thought to be about three days old, helpless and 

 downy rather than feathery. The female showed much concern and came within 

 two meters of the observers. The male was indifferent and sang as soon as the 

 observers withdrew. On June 17 the happenings at this nest were watched for 

 most of the day. The female did most of the feeding of young, making trips at 



