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208 THE CONDOR Vol. XXIV 
cies. Breeding specimens typical of both artemisiae and obscurus are at hand 
from Death Valley, the Panamint Mountains, and Independence. To add to the 
complexity of the material from this region, several of the intergrades (pos- 
sibly hybrids would be a better term) are practically indistinguishable from 
californicus, and were they taken in the San Joaquin Valley, would pass as 
examples of that form. In this regard the present case is clarified, however, by 
the exact analogy detected some years ago among the horned larks by Dr. H. C. 
Oberholser('). Briefly, the case may be summed up as follows: Where the two 
forms come together, a combination of their characters has resulted in a more or 
less typical reduplication, in certain individuals, of the characters of a third 
well-defined race occupying a distant and delimited area. 
Molothrus ater californicus, subsp. nov. 
California Cowbird 
DIAGNOSTIC CHARACTERS: FEMALES: Compared. with Molothrus ater obscu- 
rus, size larger, tail proportionately shorter, and tarsi and feet much heavier; 
coloration darker, especially below (more slaty), and streaking sharper and 
more conspicuous. Compared with Molothrus ater artemisiae, size smaller ; 
streaking of under parts narrower. Mates: The proportion of wing to tail is 
practically the same in the males of all three races, but the larger size, heavier 
tarsi and feet, together with the greater bill size of | californicus will serve as 
distinguishing characters when compared withobscurus; the smaller size, par- 
ticularly of these parts, will differentiate the race with equal facility from 
artemisiae, 
Type: Female adult, H 707, collection of Donald R. Dickey; Buena Vista 
Lake, Kern County, California; May 20, 1920; collected by Donald R Dickey 
and A. J. van Rossem; original number A. J. van R. 5366. 
Rance: In summer, the San Joaquin Valley of California, from the ex- 
treme southern end north at least to northern Mereed County, and possibly 
north to include the Sacramento Valley; also east in favorable localities to the 
Sierra foothills, as at Weldon, Kern County, and Snelling, Merced County. 
Wandering west and south in the fall to Ventura County (Oxnard), and Santa 
Barbara County (Carpinteria), and in spring at least to Los Angeles County 
(Kl Monte). Specimens examined from the following localities: Kern County: 
Buena Vista Lake, Bakersfield, Weldon; Merced County: Snelling; Fresno 
County: Mendota; Santa Barbara County: Carpinteria; Ventura County: 
Oxnard; Los Angeles County: El Monte. : 
RemArKS: We have selected a female as the type because the differences 
between the several forms are (as is the case with certain races of Agelaius) 
more pronounced and uniform among individuals of this sex than among the 
males. 
This form is apparently resident in the southern San Joaquin at all seasons 
of the year. In September, 1921, and in January, 1922, the junior writer found 
cowbirds almost, if not quite, as common in the vicinity of Buena Vista Lake 
as during the summer. No specimens were taken at these times, because for some 
reason the birds were extremely shy. <A large series of fall, winter, and spring 
specimens taken outside the San Joaquin Valley fails to disclose any birds re- 
ferable to this race, except those mentioned above. Intergradation with obscurus 
takes place in the northern part of the San Diegan District, for breeding birds — 
@) Proe. U.S. Nat. Mus, 24,1902, pp. S02-s02) 
