Vol. XXIV, pp. 163-164 June 16, 1911 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



A NEW BLUE GROSBEAK FROM CALIFORNIA. 

 BY JOSEPH GRINNELL. 



Early in 1910 an expedition was sent by the Museum of 

 Vertebrate Zoology of the University of California to the lower 

 Colorado valley, in California and Arizona. While working up 

 the extensive collection of birds obtained, my attention was 

 arrested by the appearance of the blue grosbeaks from that region. 

 Their bills are uniformly very much larger than those of the 

 form previously familiar to me and occurring in summer on the 

 Pacific slope of southern and central California. Examination 

 of specimens and literature shows that the large-billed form is 

 the one already designated and that it is the bird of western 

 California that needs to be named. 



Guiraca caerulea salicarius subsp. nov. 



CALIFORNIA BLUE GROSBEAK. 



Type. — No. 3276, Univ. Calif. Mus. Vert. Zool. ; Santa Ana River 

 bottom, near Colton, San Bernardino Co., Calif.; July 21, 1908; C. H. 

 Richardson, Jr., collector. 



Diagnostic characters. — Similar to Guiraca caerulea lazula, of Arizona 

 and Mexico, in coloration and general size, but bill much smaller and 

 proportionally less tumid, that is, outlines straighter; compared with 

 Guiraca caerulea caerulea of the South Atlantic States, blue color of the 

 male paler throughout, bill smaller, and wing and tail longer. 



Measurements of type. — Wing, 90.7 mm. ; tail, 72.6; tarsus, 20.0; culmen, 

 15.0; bill-from-nostril, 11.4; depth of bill at base, 11.9; gonys, 9.5; 

 greatest outside width of corneous portion of lower mandible, 10.4. 



Habitat. — In summer, the Lower Sonoran zone of central and southern 

 California west of the Sierran divide; in winter, unknown. 



Remarks. — This form was characterized, but not named, by Ridgway 

 (Birds N. ct Mid. Am., I, 1901, p. 610). It is paralleled in many other 

 passerine genera of the southwest, and since the characters are conspicu- 

 ous to the trained eye and are fairly constant, the only wonder is that the 

 race has not been provided with a name before. 



27— Proc. Biol. Soc. Wash., Vol. XXIV. 1911. (163) 



