A Race of the Poor-Will from Sonora
A Race of the Poor-will from Sonora.
A few years ago in considering the characters shown by a small series of Poor-wills from Bates Well, Pima County, Arizona (Trans. San Diego Sot. Nat. Hist., 8, 1936:135), I expressed the opinion that they were intergrades between Phalanoptilus nuttallii nuttallii of eastern Arizona and Phalaenoptilus nuttallii hueyi of the lower Colorado River Valley, although nearer to the former. Mr. L. M. Huey has recently collected an additional series in the same locality. In the course of a recent inspection of certain Sonora birds in the Field Museum of Natural History, I found two similar Poor-wills taken at the Providencia Mines in central Sonora, and a re-examination of five specimens from Oposura [=Moctezuma], also in central Sonora (Museum of Comparative Zoology), shows them to belorig in the same category. It is thus apparent that the birds from Bates Well are not intergrades but belong to an undescribed race which I name as
Phalaenoptilus nuttallii adustus new subspecies
Sonora Poor-will
Type.-Adult male, no. 50.513 Dickey Collection; Bates Well, Pima County, Arizona, altitude 1500 feet, June 22, 1932 ; collected by A. J. van Rossem.
Subspecific characters.-Similar to Phalaenoptilus nuttallii nuttallii of the western United States in general, but slightly paler and decidedly browner throughout, this color being apparent in the “frosting” of the head and pectoral region as well as in the plumage in general. Similar to Phalanenoptolis nuttallii hueyi of the lower Colorado River Valley and, like that race, with “frosting” light grayish brown rather than silvery, but coloration throughout decidedly darker.
Range.-Extreme southern Arizona south through the Lower Sonoran Zone at least to lat. 29’ 45’ N. in Sonora (El Alamo ; Providencia Mines; Moctezuma).
Remarks.-No differences in measurements of note are to be found between the three races here compared.
Poor-wills from extreme south-central Arizona (Upper Sonoran Zone in the Santa Rita, Atasco, and Pajarito mountains) and extreme north-central Sonora (Rancho La Arizona near Saric) are variable in color, some approaching adz&us very closely, but the great majority do not appear to be different from nuttallii from the general range of that race.
I wish to thank Dr. L. B. Bishop, the Museum of Comparative Zoology, the Los Angeles Museum, and the Field Museum of Natural History for the loan of necessary specimens. Comparative material used was as follows: adustus, 21 from localities given above; dickeyi, Lower California, 5 ; nuttallii, California, 22, Nevada, 2, Arizona, 11, Washington, 1, British Columbia, 1, Montana, 2, Texas, 2, Kansas, 2, Sonora, 9) ; hueyi, California, 15; catifornicus, California, 17.
A. J. Van Rossem
Dickey Collections, University of California at Los Angeles, June 10, 1941
