BLACK-FACED IBIS 121 
They walk rapidly, stooping very much, and probing 
the ground with their long, slender, curved beaks, 
and appear to subsist principally on the larve of the 
large horned beetle, with which their stomachs are 
usually found filled. So intent are they on seeking 
their food that the members of a flock often scatter 
in all directions and wander quite out of sight of 
each other; when this happens they occasionally 
utter loud vehement cries, as if to call their com- 
panions, or to inform each other of their whereabouts. 
Frequently one is seen to lift up its wings as if to 
fly, and, stretching them up vertically, to remain 
for fifteen or twenty seconds in this curious attitude. 
At sunset they all rise up clamouring and direct their 
flight to the nearest watercourse, and often on their 
way thither go through a strange and interesting 
performance. The flock suddenly precipitates itself 
downwards with a violence wonderful to see, each 
bird rushing this way and that as if striving to outvie 
its fellows in every wild fantastic motion of which 
they are capable. In this manner they rise and 
descend again and again, sometimes massed together, 
then scattering wide apart in all directions. This 
exercise they keep up for some time, and while it 
lasts they make the air resound for miles with their 
loud percussive screams. 
In Patagonia I first observed this Ibis roosting 
on tall trees; and, according to Azara, it possesses 
the same habit in Paraguay. He says that all the 
flocks within a circuit of some leagues resort to one 
spot to sleep, and prefer tall dead trees, bordering 
