1920] 



Swarth: Revision of Avian Genus Passerella 



111 



Creek, etc.). Each of these three areas includes places that were 

 favorite collecting grounds of certain persons (Santa Monica Moun- 

 tains: J. E. Law, L. E. Wyman, W. B. Judson, H. S. Swarth; Pasa- 

 dena: J. Grinnell, F. S. Daggett, H. S. Swarth; Claremont: W. M. 

 Pierce), and the series of Passerella are results of years of collecting 

 at these points. I believe, therefore, that these series may be taken 

 as fairly indicative of average conditions within the areas where 

 they were obtained. As to the characteristics of the three areas, the 

 Santa Monica Mountain region is widely different from the other 

 two, while the Pasadena and Claremont regions are essentially alike. 

 The part of the Santa Monica Mountains that is here included is a 

 spur extending eastward from Santa Monica Caiion about fifteen 

 miles. These hills are low, nowhere reaching an elevation of 2000 

 feet, densely brush covered, with very little large timber and very 

 little water. The mountains of the Pasadena and Claremont regions 

 are of a different character, much higher and more rugged, with 

 deep canons containing large streams of water, and with an abundance 

 of timber. 



Table 3. — Winter distribution of the subspecies of Passerella iliaca at three neighboring localities in 

 the San Diego region (see map, fig. I). Specimens listed were collected between October 15 

 and March 15. 



There are certain features in the distribution of Passerella in the 

 three sections that are at once apparent (see table 3) : the preponder- 

 ance of schistacea in the Claremont region, the restriction of hrevi- 

 cauda to the Santa Monica Mountain region, the scarcity of anj^ 

 subspecies of the Unalaschensis group in the Santa Monica Mountain 

 region, the preponderance of insularis in the Pasadena region, and 

 the preponderance of sinuosa in the Claremont region. 



