338 University of California Publications in Zoology (Vou. 24

The adult male collected (no. 42055, Hazelton, September 24) is
referred to columbarius, though darker colored than any other adult
of that subspecies that I have seen. There are nine adult male pigeon
hawks in the several collections housed in the Museum of Vertebrate
Zoology, and these exhibit an interesting range of variation. An
extreme of darkness is represented by the Hazelton bird above referred
to, but shghtly removed from that of suckleyi. At the opposite extreme,
of light coloration, is an example of richardsoni. Between, there are
seven specimens, labeled columbarius, illustrating unbroken gradation
from one extreme to the other. Thus, in adult birds as in immatures,
there is no one character of color or markings that may be taken as
absolutely indicative of any one form. The three names, columbarius,
suckleyt, and richardsoni, apply to three subspecies of one species,
between which no definite lines may be drawn.

There is this to be said, however, that the above comments are
based, not upon breeding birds, but upon specimens collected during
she migrations and in winter. The line of nicely graded adults just
described was not arranged with regard to geographic continuity.
Breeding pigeon hawks are scarce in. collections (not one was avail-
able to the present writer) and, for the most part, deductions must be
drawn as best they may from non-breeding birds.

The Hazelton series is of interest in that it includes a specimen of
suckleyt from what I believe is the northernmost point at which this
subspecies has been definitely recorded. This place is at an inter-
mediate point between humid coast and arid interior, and most of the
pigeon hawks taken there are intermediate in appearance. Of course
these birds were not found actually breeding, but the conclusion does
not seem forced that they are representative of the form that does
breed in that general region.

In this discussion I have ignored the recently described Falco
columbarius bendirei of Swann (1922, p. 66; type locality, Fort Walla
Walla, Washington). It may be possible eventually to demonstrate
the existence of this additional western subspecies, but the two eastern
specimens available to me are not to be distinguished from western
birds here regarded as columbarius.

Falco sparverius sparverius Linnaeus. American Sparrow Hawk

A fairly common summer visitant to the lowlands. A few were
seen in the open country above timber on Nine-mile Mountain, but
that was early in August and the birds noted had probably wandered