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

BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 187
Aires, Mendoza, Santa Fe, and Chaco, no definite variation is ap-
parent save that specimens from Mendoza appear someAvhat paler
and whiter below. Birds of this species easily become soiled and
most of the skins from eastern localities are considerably discolored
by dirt so that on careful examination the lio;hter color of skins from
semiarid Mendoza seems more apparent than real. Cory has stated
that specimens from Ceara average smaller than those from the
south, but a single skin from Marajo is as large as those from Buenos
Aires.
Though a bird of open country, the guira, like the ani, prefers
regions of open savannas diversified with thickets and groves so
that, though fairly common on the pampas, it was most abundant
in the partly wooded areas farther north. In southern Uruguay
and central Argentina the species is called urraca^ signifying prop-
erly a magpie, but in the north where jays occur the term urrcuca
is applied to them, and the guira is known as inrincho. It is inter-
esting to note that guira^ in the Guarani tongue signifies bird as a
group designation.
Guiras are social and range in pairs or flocks that frequently number
20 individuals. The birds feed on the ground, usually with one
member of the band perched as guard where it may survey the
country. Open pastures or savannas are frequented and the birds
are attracted by recent burns in grasslands. As they alight they
throw the tail up and the head down, and then walk or run rapidly
with long legs fully extended. At any alarm they utter a curious
rattling call that may be represented as kee-ee-ee-ee^ from which
they derive their Guarani name of piriri (meaning a crackling noise,
as the crackle of a brush fire, or the noise produced in walking
through dry weeds), and then fly off in a loose, stringing flock to
alight in company on a tree, post, or fence. The flight is slow and
Aveak, accomplished by a brief beating of the wings, followed by a
short sail in which the wings are held stiffly extended. On the wing,
head and tail are held at a slightly higher level than the back. The
long tail is held at various angles when the birds are at rest, while
the wings may be drooped and the crest lowered or raised. Curiosity,
interest, or indifference are expressed in constantly changing
attitudes, many of which are bizarre and unusual so that the long,
slenderly formed guiras are always of interest. On cool mornings
flocks rest in the rays of the sun with hanging tail, drooping wings,
and fluffed out feathers, a sight so frequent that in el sol como un
pirincho is a common saying for any one who basks in the sun's rays
on a cold morning.
The song of the guira, if such it may be called, is a series of
discordant notes of great carrying power, exactly like the noise
produced by blowing on a grass blade held taut betvveen the thumbs
;