Bulletin - United States National Museum - si-pddr - Smithsonian ...

BIRDS OF AKGENTINA, PARAGUAY, URUGUAY, AND CHILE 171
it may be j^itch dark. In olden times they were prized for their
watchfulness at night, which gave warning of the approach of any
possible enemies, and it is to this that the sentiment in Avhich they
are held at present is due. Though peons rob their nests continually,
comparatively few of the terus are killed, which may account for
their abundance in settled regions.
The species was found in practically all of the regions visited. In
the Chaco where the country is broken by frequent tracts of monte
they were less common than farther south in more open country.
During winter they were frequently observed in pairs that often
seemed to have a restricted range where they were observed daily.
They traveled to some extent, however, and were frequently seen in
strong, direct flight, passing high overhead. In the Chaco back of
Puerto Pinasco they were seen at a distance of 200 kilometers west
of the Paraguay River. A female that I secured on September 6,
1920, at Kilometer 80, was about ready to breed. It is possible that
another form may be described from this region as this specimen,
in common with one or two seen from southern Brazil, has the black
line down the foreneck considerably restricted.
The well-watered eastern pampas form the true metropolis of the
teru teru, as though the species frequents open, grassy plains, it
seeks always the vicinity of water. In eastern Buenos Aires the
birds were especially abundant and at the end of October apparently
were breeding. At this season they became especially pugnacious
in pursuit of passing hawks and storks, Avhile one even dashed
repeatedly at an inoffensive European hare that loped along ahead
of me. It Avas frequent to see two pairs of terus high in air in a
display flight in which the fully extended wings, marked prominently
with black and white, were waved slowly. The birds were
observed west to Carhue, Buenos Aires, but none were noted at
Victorica, Pampa, though I was told that they occurred there in
wet seasons. A few seen at General Koca, Eio Negro, were supposed
to be the present bird but may have been cMlensis.
In Uruguay terus were common. On January 22 between San
Carlos and Rocha I observed several bands of 20 or 30 gathered on
open spaces on the banks of little arroyos running with clear water.
These bands, observed commonly until the end of February, were
composed of old and young, all less noisy than earlier in the season.
The birds rested or fed in loose flocks that ran aside to permit
passage of vehicles or men on horseback. At this season terus were
in molt and their resting places were strewn with cast feathers.
Grasshoppers, present in great abundance, were a favorite food, and
the birds on the whole must have a considerable economic importance.
A young bird only a few days old was captured near Lazcano on
February 7. An adult taken on the following day is representative