172 University of California Publications in Zoology [Vol. 21 



evidence that the species was nesting in the mountains where it was 

 taken, though no more of the birds were seen. If I am correct in 

 ascribing this specimen to monoensis, it may indicate that the sub- 

 species occupies a rather extensive summer habitat on the summits of 

 certain of the desert mountains. However this may be, the only 

 breeding specimens at hand that appear to be unequivocally of the 

 race monoensis (aside from the one exception above noted) are all 

 from a relatively limited region about Mono Lake. Specimens from 

 Mammoth, immediately to the southward, appear to be niariposae, 

 as are the birds still farther south on the east slope of the Sierras 

 (see p. 175). Furthermore, between Mono Lake and the Panamint 

 Mountains lie the White Mountains with the very different subspecies 

 canescens. It is hardly reasonable to suppose that the latter race 

 would be thus interposed between the known habitat of monoensis at 

 Mono Lake, and an outlying colony such as seems to be indicated 

 by the Panamint Mountains specimen. Altogether, the capture of 

 the latter is an extremely puzzling oecurrence. 



While engaged in this study of Passerella, I took occasion to request 

 Mr. Donald D, McLean to collect for the Museum specimens of fox 

 sparrows from the vicinity of his home, hear Coulterville, Mariposa 

 County, California. There were but few of any of the subspecies at 

 hand from the Sierra Nevada foothills, and he had told me that there 

 were many "thick-billed sparrows" in that region during the winter 

 months. To my surprise, of the nine birds of this type that he sent 

 in, collected during December and January, eight proved to be m.ono- 

 e7isis. Coulterville is at the west base of the Sierra Nevada, almost 

 due west of Mono Lake, though, of course, with the whole width of 

 the mountain chain between the two points. There is a specimen of 

 monoensis at hand taken in Yoseniite Park, October 1, and four others 

 from Horse Corral Meadow, in the mountains of Fresno County, 

 secured between September 19 and 23, indicating that the subspecies 

 spills over the crest of the Sierras on to the western slope in the 

 migration from the summer home. If the main winter habitat should 

 prove to be in the western foothills of the Sierra Nevada as is indi- 

 cated by the Coulterville birds, it would imply a rather remarkable 

 migration route — almost due east and west, rather than north and 

 south. 



There are a few scattered winter birds at hand from points in 

 Los Angeles County, including Santa Catalina and San Clemente 

 islands, all taken west of the desert divides. Extreme dates of capture 



