178 U. S. NATIONAL MUSEUM BULLETIN 211 



Harry S. Swarth (1929) makes the following comments on Ridg- 

 way's type and the status of this form in Arizona: 



It [the type] differs from the mode of the Agelaius of the lower Colorado Valley, 

 to which the name sonoriensis has been generally applied, in having a distinctly 

 heavier, stubbier bill, in which particular it can not be matched in a large series 

 of Colorado River birds. In coloration, however, it is closely similar to some 

 females from the Colorado River, and correspondingly different from the mode 

 of nevadensis and fortis. Altogether, I am disposed to let the name sonoriensis 

 continue to stand for the Colorado River form, and to regard the type specimen 

 as a stray or migrant, a winter-taken bird from beyond the normal breeding range 

 of the subspecies. There has already been such a confusion of the names applied 

 to this race, as well as to the proper type locality, that I am unwilling to suggest 

 a change that might cause further trouble. 



The point I wish to emphasize here is the fact that there are two subspecies of 

 Agelaius phoeniceus breeding in southern Arizona, one occupying the valley of 

 the lower Colorado River and its tributaries as far east as Tucson, the other, the 

 region east from the Santa Catalina and Santa Rita mountains. Breeding birds 

 from Phoenix and Tempe are mostly indistinguishable from Colorado Valley 

 specimens. Breeding birds from near Tucson are intermediate, some of them 

 having distinctly heavy and stubby bills, as compared with the slender-billed 

 western race, but on the whole they are best associated with the Colorado Valley 

 subspecies. 



If we accept the conclusions of van Rossem and Swarth, which 

 seem reasonable in view of our present knowledge, we must revise 

 our ideas of the breeding range of the Sonora redwing. For a number 

 of years in the past this form was supposed to breed in suitable 

 localities entirely across the arid portions of southern Arizona and 

 even in extreme southwestern New Mexico, but now its breeding range 

 seems to be limited to the area cited under "distribution," below. 



DISTRIBUTION 



The range of the Sonora redwing lies in southeastern California and 

 Nevada to western Mexico. It is resident from southeastern Cali- 

 fornia (Indio), southern Nevada (opposite Fort Mohave, Arizona), 

 central-western, central, and southeastern Arizona (Mohave, Wikieup, 

 SafTord); south to northeastern Baja California (Colorado Delta) and 

 northern Sonora. It winters south to southern Baja California 

 (Santiago, San Jose del Cabo), southern Sinaloa (Mazatlan, Escuin- 

 apa), and central Durango (Papasquiero). 



