TIIE. CO.lB.OR olurno X ?optornber-Ootobor, 191;? Number A REVISION OF THE CALIFORNIA FORMS OF PIP1LO MACULA. TUS SWAINSON, WITH DESCRIPTION OF A NEW SUBSPECIES By H. S. SWARTH WITH ONE MAP (Contribution from the Museum of Vertebrate Zoology_ of tile University of California) HE SPOTTED TOWHEE (Pipilo maculatus) is a common and character- istic bird over a large part of California. Its range is included almost olto- gether in the Upper Sonoran and Transition zones. Its absence from nearly all parts of Lower Sonoran is probably chiefly due to the lack of suitable associa tional conditions over most of the arid regions comprising this zone; for in some places, as in the Lower Sonoran San Joaquin Valley, this towhee is found, though in small numbers, in the limited portion of the region which is adapted to its needs. Six geographic races of this species are here recognized as occurring within the state. Five of them permanently occupy definite and fairly well-defined areas within the state; the sixth occurs only as the merest straggler. On the accompany- ing map (fig. 47) is shown the distribution in California of the five resident su?- species, platted from specimens and data in the Museum of Vertebrate Zoology. A comparison of this with Grinnell's. (I9o2) map of the faunal areas of the state
shows a close paralleling of the outlines of the ranges of the various subspecies
with those of certain of the faunal areas. This, of course, is what is to be expected in a non-migratory and somewhat variable Species, and occurs in this towhee as in Melospiza, Thryomanes, and certain other birds. Where there are striking differ- ences in the two maps they can in most cases be explained satisfactorily by the towhee's known manner of zonal'distribution. In California the species is restricted substantially to the Upper Sonoran and Transition zones, debarred from the extremes of Lower Sonoran and Boreal, but otherwise not affected by zonal changes. Thus the Colorado Desert (taking the term as it is used on Grinnell's map), lying wholly within the Lower Sonoran Zone, has no representative of the species, except ?. m. curtatus as a winter visit- ant in a restricted portion of the region.
