166 BIRDS OF LA PLATA 
voice exerted to its utmost pitch, and expressive of 
agony, frenzy, and despair. A long, piercing shriek, 
astonishing for its strength and vehemence, is suc- 
ceeded by a lower note, as if in the first one the 
creature had wellnigh exhausted itself. The double 
scream is repeated several times; then follow other 
sounds, resembling, as they rise and fall, half-sup- 
pressed cries of pain and moans of anguish. Suddenly 
the unearthly shrieks are renewed in all their power. 
This is kept up for some time, several birds scream- 
ing in concert ; it is renewed at intervals throughout 
the day, and again at set of sun, when the woods and 
marshes resound with the extravagant uproar. I have 
said that several birds unite in screaming; this is 
invariably the case. I have enjoyed the rare pleasure 
of witnessing the birds at such times; and the 
screams then seem a fit accompaniment to their 
disordered gestures and motions. 
A dozen or twenty birds have their place of reunion 
on a small area of smooth, clean ground surrounded 
by rushes or sedges; and by lying well concealed 
and exercising some patience, one is enabled to watch 
their proceedings. First one bird is heard to utter 
a loud metallic-sounding note, three times repeated, 
and somewhat like the call of the Guinea-fowl. It 
issues from the reeds or rushes, and is a note of 
invitation quickly responded to by other birds on 
every hand as they all hurriedly repair to the 
customary spot. In a few moments, and almost 
simultaneously, the birds appear, emerging from 
the reeds and running into the open space, where 
