22 6 The Naturalist in La Plata. 



the other notes of the female behig long powerful 

 notes with a trill in them ; but over them sounds 

 the clear piercing voice of the male, ringing forth 

 at the close with great strength and purity. The 

 song produces the effect of harmony, but, comparing 

 it with human singing, it is less like a duo than a 

 terzetto composed of bass, contralto, and soprano. 



At certain times, in districts favourable to them, 

 the chakars often assemble in immense flocks, 

 thousands of individuals being sometimes seen con- 

 gregated together, and in these gatherings the birds 

 frequently all sing in concert. They invariably — 

 though without rising — sing at intervals during the 

 night, " counting the hours," as the gauchos say; 

 the first song being at about nine o'clock, the 

 second at midnight, and the third just before dawn, 

 but the hours vary in different districts. 



I was once travelling with a party of gauchos 

 when, about midnight, it being intensely dark, a 

 couple of chakars broke out singing right ahead of 

 us, thus letting us know that we were approaching 

 a watercourse, where we intended refreshing our 

 horses. We found it nearly dry, and when we 

 rode down to the rill of water meandering over the 

 broad dry bed of the river, a flock of about a thou- 

 sand chakars set up a perfect roar of alarm notes, 

 all screaming together, with intervals of silence 

 after; then they rose up with a mighty rush of 

 wings. They settled down again a few hundred 

 yards off, and all together burst forth in one of 

 their grand midnight songs, making the plains echo 

 for miles around. 



There is something strangely impressive in these 



