(SORDID SPINE-TAIL.)
+Synallaxis sordida+, _Hudson, P. Z. S._ 1872, p. 543 (Rio Negro);
_Scl. et Salv. Nomencl._ p. 64; _Scl. P. Z. S._ 1874, p. 23;
_Durnford, Ibis_, 1878, p. 396 (Centr. Patagonia); _White, P. Z.
S._ 1883, p. 39 (Cordova); _Barrows, Bull. Nutt. Orn. Cl._ viii.
p. 208 (Entrerios).
_Description._--Above earthy brown; wing-feathers blackish brown,
their basal parts pale chestnut-brown, forming a transverse bar;
tail blackish, the three outer rectrices and outer web of the fourth
rectrix on each side wholly pale chestnut-brown; beneath pale earthy
brown, clearer on the belly, and with a bright fulvous spot on
the throat; under wing-coverts pale cinnamomeous; bill and feet
blackish: whole length 6·5 inches, wing 2·3, tail 2·8. _Female_
similar.
_Hab._ Patagonia and East Argentina.
This species, which, on close comparison, is at once distinguishable
from _S. modesta_ by the absence of any black colour on the three
exterior pairs of tail-feathers, ranges from the extreme north of the
Argentine Republic to Patagonia, where it is quite common, and is
invariably found in dry situations abounding in thorny vegetation.
It does not migrate, and lives with its mate in thorny bushes, but does
not attempt to conceal itself, and sits much on the summit of a bush,
where the male in spring utters at intervals a clear trilling call.
In its inactive disposition, slow deliberate movements, also in its
language, it strikingly resembles the _Phacellodomus ruber_. In its
nidification it also comes nearest to that species. The nest is a large
structure of sticks, eighteen inches to two feet long, placed upright
among the twigs at the summit of a bush. From the top where the entrance
is placed, a winding passage leads down to the chamber at the bottom of
the nest; this is lined with soft dry grass and feathers, and four pure
white eggs are laid.