Nov:, 1922 DISTRIBUTION OF MOLOTHRUS ATER IN CALIFORNIA 207 
following localities: Imperial County: Calexico, Bard, Lano, Potholes, Pilot 
Knob; Riverside County: Mecca, Neighbors, Riverside; San Bernardino County: 
Lavic, Yermo, Victorville, Colton; Inyo County: Death Valley, Panamint Moun- 
tains, Independence, Shoshone; San Diego County: San Diego, National City, 
Borego Springs, Vallecito; Orange County: Anaheim Landing; Los Angeles 
County: Baker, Los Angeles, El Monte, Pasadena; Ventura County: Oxnard; 
Santa Barbara County: Goleta. 
Remarks: Broadly speaking, the life zone occupied by obscurus is Sonoran, 
with centers of abundance in the Lower Sonoran Zone along the Colorado River, 
at desert oases, such as Mecea, and in the irrigated sections of the Imperial Val- 
ley. The race is probably resident over its entire California range; certainly 
so in the southern part of the State. Specimens from the northern part of the 
San Diegan District are intermediate toward californicus. 
Molothrus ater artemisiae Grinnell 
Nevada Cowbird 
Range in California: In summer, the east-central section of the State, from 
Death Valley, the Panamint Mountains, and Independence, north to Mono lhake ; 
also the northeastern section, in the Modoe region. In migration, and in winter, 
widely distributed over most of the State. Record stations outside the normal 
breeding range are: Los Coronados Islands (Lower California), September 5; 
Farallon Islands, June 2; Borego Springs, April 30; Neighbors, October 14; 
Yermo, June 7; and Mount Bullion, December 27. The record from the Sacra- 
mento Valley cited by Baird(') may pertain to this form or to californicus. Of 
the 49 specimens examined, 26 are from the following California localities: Los 
Coronados Islands (Lower California); San Diego County: Borego Springs; 
Riverside County: Neighbors; San Bernardino County: Yermo; Inyo County: 
Furnace Creek Ranch, Death Valley, Panamint Mountains, Independence, Laws; 
Mono County: White Mountains, Mono Lake, Oasis; Modoc County: Alturas; 
Mariposa County: Mount Bullion. 
REMARKS: As a breeding bird, the Nevada Cowbird is much more widely 
distributed zonally than either of the other forms occurring in California, since 
it ranges from Transition (Alturas), through Upper Sonoran (Mono Lake and 
Owens Valley), to extreme Lower Sonoran in Death Valley. Moreover, this 
race is distinctly migratory, whereas obscurus and californicus appear to be 
nearly or entirely resident. The sporadic occurrences during the summer at 
Yermo and on the Farallones can be most logically accounted for by considering 
these individuals as late or strayed migrants. 
A certain amount of intergradation takes place between artemisiae and 
obscurus in Death Valley, the Panamint Mountains, and Owens Valley, par- 
ticularly in the southern part. In addition, certain rather small examples of 
artemisiae from Mono Lake are undoubtedly accounted for by an infusion of 
obscurus blood. However, the blending of the two races is by no means the 
gradual one which is generally found in the intermediate area between two sub- 
species. This very imperfect fusion of the two forms probably indicates either 
a recent invasion of the range of one form by the other, or else a recent simul- 
taneous occupation by both forms of an area formerly uninhabited by the spe- 
() Reports of Explorations and Surveys from the Mississippi River to the Pacific 
Ocean, 1853-56, vol. 9, pt. 2, pp. 524-525. 
