168 University of California Puhlications in Zoology [Vol. 21 



of Passerella. Such variation in most eases takes the form of inter- 

 gradation toward megarhyncJius, sometimes in slight degree, occasion- 

 ally to an extent that makes the placing of the individual specimen 

 a matter of arbitrary decision. It is noteworthy that the birds from 

 Snow Mountain, the southernmost known breeding station of hrevi- 

 cauda, have the bill perceptibly larger than in the Yolla Bolly birds, 

 to the northward. The latter thus appear to show in some degree 

 intermediateness toward megarhyncJius. In but a few cases, among 

 winter birds, is there any occasion for confusion with stephensi. In 

 faded and worn plumage there may sometimes be difficulty in deciding 

 between these two subspecies, but there are no fresh-plumaged birds 

 at hand that are at all equivocal. 



In addition to the normal variation just described, there is one 

 specimen at hand (coll. W. L. Dawson, male, "Santa Barbara Co., 

 Cal.," November 22, 1913) that shows a noteworthy trace of albinism. 

 It has a pure white area on the forehead, extending from eye to eye, 

 from the base of the bill backward to a maximum width of six milli- 

 meters. On the left side it includes the lores and extends below the 

 eye over the cheek. This white marking is of interest througli its 

 appearance of being an unusual extension of the two whitish spots 

 between eyes and nostrils, present to a greater or less extent in prac- 

 tically all fox sparrows. 



The series of breeding birds at hand sheds little light upon the 

 dates of arrival and departure of this subspecies upon its nesting 

 ground, for they are all midsummer specimens. The winter birds 

 from Marin County were taken on dates ranging from September 23 

 to April 29. Specimens collected by Mailliard on September 23 were 

 believed by him to have been raised possibly at the spot where they 

 were taken (Mailliard, 1912, p. 63), a supposition that has not as yet 

 been verified. One specimen at hand from Nicasio, Marin County 

 (Carnegie Museum, no. 29698), bears the date of "June" 28. The 

 label now attached to this skin is obviously not that of the original 

 collector. In all probability a mistake was made in copying, so that 

 this skin can not be admitted as evidence of the breeding of hrevicauda 

 at this place. 



From southern California by far the earliest fall migrant is 

 Bowles' specimen from Little Pine Mountain, Santa Barbara County, 

 taken August 30. From the Santa Monica Mountains there are speci- 

 mens from October 4 to January 19, but there is little doubt that the 

 birds arrive earlier and depart later than is indicated by these dates. 



