120 BIRDS OF LA PLATA 
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BLACK-FACED IBIS 
Theristicus caudatus 
Sides of throat and lores bare, skin black; top of head and lower 
part of neck in front reddish chestnut ; neck white ; back and wings 
grey with green reflections; tertials and outer webs of secondaries 
for two-thirds of their length white, remainder dark green ; primaries 
dark green; rump light green, bronzed; tail dark bronze green ; 
under parts black; length 33, wing 16.25 inches. 
Tus very fine Ibis, called Mandurria 6 Curucdu by 
Azara and Vanduria de invierno (Winter Vanduria) in 
the vernacular, is one of the most interesting winter 
visitors from Patagonia to the pampas of Buenos 
Ayres. It is found in Chili, and has even been 
obtained as far north as Peru. On the east side of 
the continent it is most abundant (during the cold 
season) about latitude 37 deg. or 38 deg. Its summer 
home and breeding ground appears to be in the 
extreme south of the continent, its eggs having been 
obtained on the Straits of Magellan by Darwin, and 
later by Dr. Cunningham, who only says of it 
that it is a shy and wary bird, that goes in flocks of 
from four to eight, and has a cry resembling qua-qua, 
gua-qua. But he might just as well have spelt it 
quack-quack, since qua-qua fails to give the faintest 
idea of the series of hard, abrupt notes of extra- 
ordinary power the bird utters, usually when on the 
wing, which sound like blows of a powerful hammer 
on a metal plate. On the pampas this Ibis appears 
in May, frequents dry grassy situations, and goes 
in flocks of a dozen to forty or fifty individuals. 
