with white tips to the under tail-coverts; axillaries slaty-grey with white bases; lower primary-coverts
slaty-grey; lower secondary-coverts white with slaty-grey bases.
Geocichline markings on inner webs of quills, white.
“ Bill dull b lack; front of legs, feet, and claws greenish-yellow; back of the former dirty yellow;
iris dark brown ** (Davison).
Second primary intermediate in length between the third and fourth; outer tail-feathers 0*15
inch shorter than the longest; length of wing 4*9 to 4*4 inches, tail 3*5 to 3T inches, culmen 0*93 to
0*81 inch; bastard-primary much shorter than the primary-coverts, its exposed portion measuring 0*7
to 0*6 inch.
The female is very different from the male. General colour above warm olive-brown, inclining
to slaty-brown on the lower back and rump; wing-coverts russet-brown; quills dusky brown,
externally russet-brown, with a pale margin to the first primary; tail-feathers dusky brown, with a
russet tinge, the two outer ones with a tiny spot of white at the t ip ; head a little more russet than
the back, the eye-stripe fulvous and not so distinct as in the male; ear-coverts ochreous-buff, mottled
with blackish edgings to the feathers; cheeks ochraceous, with a blackish line above and below,
forming a distinct moustachial streak; under surface of body ochraceous, whiter on the throat, which
is spotted with dusky ; the fore-neck and breast slightly more rufous and mottled with blackish sub-
terminal bars to the feathers, less marked on the sides of the body and flanks; lower breast and
abdomen pure white ; thighs brown; under tail-coverts white, with dusky bases; under wing-coverts
ochraceous-brown; axillaries white, with brown tips ; quills dusky below, with the wing-band buffy
white : “ bill dark brown, the lower mandible and gape dirty yellow to the angle of the gape; feet
and claws orange-yellow; iris dark brown” (W. Davison). Total length 9 inches, culmen 0-8 inch,
wing 4*5 inches, tail 3*0 inches, tarsus 1*05 inch.
Young birds of the year may be distinguished by the pale ochre tips to the wing-coverts.
The Siberian Ground-Thrush is nearest allied to Geocichla wardi, and may possibly be almost as
closely related to G. schistacea. No other species belonging to the genus has a well-marked pale
eye-stripe, except G. ncevia, in which it is chestnut-buff. The absence of pale tips to the upper tail-
coverts not only excludes G. wardi, but also G. pinicola, which has traces of an eye-stripe. The
latter species may be also further excluded, together with G. schistacea, by the white axillaries.
G. ncevia may be excluded by the Oreocichline pattern of its primaries, and probably by its
unspotted dark buff throat; but as the young in first plumage of both birds are unknown, the
latter character must be accepted with caution.
The diagnosis of the Siberian Ground-Thrush must therefore stand as follows:—
A pale stripe over each eye, white and very conspicuous in the male.
Upper tail-coverts uniform slate-grey or brown.
Axillaries white on their basal half only.
Outer webs of primaries uniform in colour from end to end.
The last-mentioned character also excludes G. pinicola.
The female of G. sibirica resembles very closely that of G. wardi, but the latter may be easily
distinguished either by the pale tips of its upper tail-coverts, or by the greater amount of white on
the outermost feather on each side of its tail, which generally extends for more than an inch, whilst
that of G. sibirica rarely extends for more than half an inch.