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,ffizianzes, 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-
giniatus, 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
scttetti. 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 brovn tints are even less intense and extensive than in virffiniatts.
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 larger. 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 rferences 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.