Page:Condor7(6).djvu/23

 x7o I VOL. VII The Pacific Nighthawk BY JOSEPH GRINNELL Chordeiles virginianus hesperis new subspecies. UBSPECIFIC CHARACTERS--{ost nearly resembling Ch. v. virginianus, but:--outer surface of closed wing grayer toned; lowe.r tail-coverts and feathers of belly region more narrowly and sparsely dark-barred; and, in the male, white patches on throat, wings, and tail more extensive. TYPE-- adult; No. 69x 7 Coll. J. G.; Bear Lake, 6700 feet alt., San Bernardino Mts., Califor- nia; July 3 o, x9o5; collected by J. Grinnell aud J. Dixon. DISTRIBUTIoN--The race is based on 4 fresh specimens from the San Bernardino Mountains, California, where the species b"ceds in the Canadian Zone (7oo0-90oo feet), descending in' its evening insect-hunts thru Transition (as low as 5000 feet). An example from Newport, Oregon, and several from the central Sierras (Amador and El Dorado Counties), California, are closely similar; so that it is probable that Ch. v. hexperis is the race visiting the whole Pacific Coast of the U.S. in summer, and breeding in the Canadian Zone from the San Bernardino Mountains northward. RElUARKS--'h. v. hesperis is equal in size to the largest northern representa- tives of Ch. v. vir,ffizianzes, that is, somewhat larger than examples of the latter race from Marylaud and Virginia, and notably larger than the several races from the southern border of the U.S. In tone of coloration the male is much darker than in either C/z. v. sennetti or Ch. v. henr,i. Attho somewhat lighter than vir- giniatus, this is in the direction of pale gray and white rather than ochraceous. The extended mottling of the otherwise blackish feathers dorsally is responsible for this lighter tone, and especially notable is the extensive silvery gray mottling on the wing coverts. Yet this dorsal tone does not nearly reach the paleness of scttetti. The decrease in width and numbers of the dark bars on the belly and crissum gives that portion of the lower surface a decidedly whitish cast, as hcno,i. But instead ofagreat extension of ochraceous or tawny dorsally as in the latter form, the brovn tints are even less intense and extensive than in virffiniatts. The I';,c-e region of hesperis is much paler than in virginianus, due to replacement of restricted deep tawny'markings with larger ones of paleochraceous. The same is true of the chest. The white palches on the throat, primaries, and rectrices of hesperis average decidedly larger. The patch on the outer primary invades across the shaft to include the outer web; aud the same is observable of the patches on the tail-feathers. Many of the above remarks apply also to the female, except of course where sexual differences are involved. The female of hesperisis gray rather than tawny, and is thus at once distinguishable from the female of henryi. The nighthawks of the West deserve thoro overhauling. It is evident from the relatively scant material at hand that the name "henryi," as generally employed late, is an aggregate, including at least three races. The birds breeding in portions of southern Texas are altogether different from those of Arizona and New Mexico (henryi), while Rocky Mountain examples differ from both. I have seen no specimens of true henryi from California, and it is probable that all, or nearly all, of our rferences to hen:,i belong under the new name hesperis. Material is de- sirable from many localities--well-prepared skins, free from grease. Nighthawks are troublesome to save in good shape; and as I have lately learned, to give proper results a nighthawk skin demands about three times the time and patience that most any other bird does. I am under obligation to the United States National Museum, thru Dr. C. W. Richmond, Acting Curator of its Division of Birds, for the loan of a pertinent series of nighthawks. Pasadena, California.