(HUDSON'S SPINE-TAIL.)
+Synallaxis hudsoni+, _Scl. P. Z. S._ 1874, p. 25; _Durnford, Ibis_,
1877, p. 36, et 1878, p. 396 (Chupat, Central Patagonia);
_Barrows, Bull. Nutt. Orn. Cl._ viii. p. 209 (Azul, Sierra de
la Ventana). +Synallaxis sclateri+, _Cab. J. f. O._ 1878, p. 196.
_Description._--Above fulvous brown, mottled with black, each
feather being marked with a large black spot; on the upper part of
the back the feathers are faintly edged with whitish grey; wings
blackish, basal halves of feathers pale clear brown, forming a
transverse bar, the terminal part of the feathers slightly edged on
the outer webs and tips with ochraceous; tail blackish, the outer
pair of rectrices and broad tips of the next two pairs on each side
very pale brown, the two middle feathers broadly margined on both
webs with pale greyish brown; beneath pale ochraceous brown, with a
pale sulphur-yellowish gular spot; flanks with a few black marks;
under wing-coverts light cinnamon; bill and feet pale horn-colour:
whole length 7·8 inches, wing 3·2, tail 3·5. _Female_ similar.
_Hab._ Argentina.
This Spine-tail, which Sclater has named after me, is the Argentine
representative of _S. humicola_ of Chili. It is common on the pampas,
and is sometimes called by the gauchos "_Tiru-riru del campo_," on
account of its resemblance in the upper plumage and in language to
_Anumbius acuticaudatus_, which is named "_Tiru-riru_," in imitation of
its call-note. The addition of _del campo_ signifies that it is a bird
of the open country. It is, in fact, found exclusively on the grassy
pampas, never perching on trees, and in habits is something like a
Pipit, usually being taken for one when first seen. It is quite common
everywhere on the pampas, and specimens have also been obtained in
Cordova, Uruguay, and Patagonia.
This Spine-tail is resident, solitary, and extremely timid and stealthy
in its movements, living always on the ground among the long grass and
cardoon-thistles. At times its inquisitiveness overcomes its timidity,
and the bird then darts up three or four yards into the air, and jerking
its tail remains some moments poised aloft with breast towards the
intruder, emitting sharp little notes of alarm, after which it darts
down again and disappears in the grass. When driven up it has a wild
zigzag flight, and after reaching a considerable height in the air darts
down again with astonishing swiftness, and comes back to the very spot
from which it rose. It is, however, incapable of sustained flight, and
after being flushed two or three times refuses to rise again. In spring
the male perches on the summit of a cardoon-bush, or other slight
elevation, and at regular intervals utters a pleasing and melancholy
kind of song or call, which can be heard distinctly at a distance of a
thousand yards, composed of four long clear plaintive notes, increasing
in strength, and succeeded by a falling trill. When approached it
becomes silent, and dropping to the ground conceals itself in the grass.
Under a cardoon-bush or tussock of grass it scoops out a slight hollow
in the ground, and builds over this a dome of fine dry grass, leaving a
small aperture arched like the door of a baker's oven. The bed is lined
with dry powdered horse-dung, and the eggs are five, bluntly pointed and
of a very pale buff colour. The interior of the nest is so small that
when the five young birds are fledged they appear to be packed together
very closely, so that it is difficult to conceive how the parent bird
passes in and out.
The nest is always very cunningly concealed, and I have often spent days
searching in a patch of cardoon-bushes where the birds were breeding
without being able to find it.