1909] Grinnell—A New Cowbird. 277 
(Gmelin), of the Lower Sonoran zone in Arizona and south- 
eastern California, but much larger.' 
Rance—Upper Sonoran and Transition zones of the Great 
Basin region of the western United States. This is practically 
coincident with the range of the sage-brush (Artemisia triden- 
tata). 
RemMArKS.—The differences between the three forms of cow- 
birds under consideration lie chiefly in their relative sizes and 
proportions. Between the males I can detect no color differences 
of importance. The brown of the head appears no paler in the 
western forms, artemisiae and obscurus, than in the eastern form, 
ater. The steely reflections of the body plumage vary slightly 
from deep bluish to bronzy; but as far as I am able to judge, 
these are purely individual qualities. 
The single female of artemisiae (no. 8824) from Humboldt 
County, Nevada, is distinctly paler than eight adult females of 
ater from the eastern United States. It is of a drab color through- 
out, very much paler and more clay color on the throat, whereas 
the eastern birds are slaty hair brown, with less abruptly con- 
trasted grayish throat. These color differences are very similar 
to those exhibited between obscurus (of which seven female 
specimens are at hand) and ater. In other words, the female of 
artemisiae is like that of obscurus in color. 
The characters by which the three cowbirds are best dis- 
tinguished may be comprehended by an examination of the three 
tables of measurements of male birds presented herewith. The 
relative sizes and proportions in the females of the three sub- 
1 As to the nomenclatural treatment of the three forms here distinguished, 
I am reluctantly following recent precedent. The genus Molothrus contains 
only these three, and one other somewhat more divergent form, Molothrus 
atronitens (Cabanis), from northern South America. I have no evidence 
whatever that the three forms, ater, artemisiae, and obscurus, intergrade con- 
tinuously and geographically between each other. In other words their 
distinctness is specific on any criterion excepting those of relatively close 
similarity in gross appearance, and individual overlapping in separate char- 
acters. Certainly the trinomial or subspecifie form of name as used here 
indicates no different order of genetic entity from that existing, say, between 
the three ‘‘species’’ of flickers, or the three meadowlarks, occupying the 
same relative areas. This is merely a protest against the very evident ten- 
dency among ornithologists nowadays to ‘‘reduce’’ all congenerie forms in 
plastic groups to subspecifie status. Indeed it might even be urged with 
reason that trinomials have outlived their usefulness, and that a pure bi- 
nomial system, as consistently followed by Sharpe in his ‘‘Hand-List of 
Birds,’’ is adequate and decidedly less cumbersome. 
