1926] Swarth: Birds and Mammals from the Atlin Region 107

The immature birds are like the adults with the exception of the
tail. The tail feathers are dark sooty brown (the same color as the
body plumage) on the outer web, lighter colored on the inner web, and
crossed by eight or nine blackish bands. The tail pattern, essentially
similar to that of immature calwrus, differs from conditions in that
form in being darker (even than in the darkest calurus), and in that
the cross-bars are broader and fewer in number. Often, too, in young
harlani the cross-bars tend to be U-shaped or V-shaped on individual
feathers, rather than extending horizontally across. In two specimens
there is a faint tinge of rufous at the tip of the tail. These hawks are
generally dark colored birds but differ from even the darkest phase
assumed by calwrus (of which there are both adult and young at
hand) in their sooty hue. In calwrus there is a great deal of rich
brown or chestnut in the coloration, which is altogether lacking in
the Atlin birds.

In this series of specimens there is some variation, shown prin-
cipally in extent of the partly concealed white markings. In the
darkest colored birds the white markings in the body plumage are

mostly reduced to small paired spots on feathers that are blackish over
most of their area. The white markings are almost entirely concealed ;
the birds are almost uniformly dark. On the thighs and tibial plumes
there are the merest flecks of whitish. The lightest extreme is repre-
sented by a bird with broadly white-barred thighs and tibial plumes,
conspicuous bars and blotches on breast and belly, and with chin and
throat mostly white.

The ‘‘soft parts’’ of two of the birds collected were colored as
follows. No. 44730; ¢ juv. (just out of the nest): Eye stone gray;
feet pale greenish yellow; bill black; cere and gape greenish.
No. 44731; 2 ad: Eye dark sepia; feet greenish yellow; bill mostly
black, tinged with bluish along cutting edges; cere and gape greenish.

One fact stands out clearly ; these birds are identical with the Falco
harlani of Audubon (1830, pl. 86), which is the Buteo borealis
harlami of the A. O. U. Check-list (1910, p. 158). Our two adults
are closely similar to Audubon’s plate, and they answer exactly the
description of Audubon’s type specimen given by Sharpe (1874,
p. 191). The fact that the supposed young of harlami as described by
Sharpe (loc. cit) is not at all like the young birds I collected is of no
moment, for Sharpe’s bird (from ‘‘ Western Mexico’’) was not harlami
at all. It appears to be the young of calurus. The same sort of mis-
take was made by Cassin (in Baird, 1858, p. 24) where one phase of