46 BIRDS OF LA PLATA 



two thousand birds. When flying the flock is very 

 much scattered, and does not advance in a straight 

 line, but the birds move in wide circles at a great 

 height in the air, so that a person on horseback 

 travelling at a canter can keep directly under them 

 for two or three hours. On the ground one of these 

 large flocks will sometimes occupy an area of half a 

 square league, so widely apart do the birds keep. I 

 have dissected a great many and found nothing but 

 coleopterous insects in their stomachs ; and indeed 

 they would not be able to keep in such large com- 

 panies when travelling if they required a nobler 

 prey. 



At the end of one summer a flock numbering 

 about two hundred birds appeared at an estancia 

 near my home, and though very much disturbed 

 they remained for about three months, roosting at 

 night on the plantation trees, and passing the da^ 

 scattered about the adjacent plain, feeding on grass- 

 hoppers and beetles. This flock left when the weather 

 turned cold ; but at another estancia a flock appeared 

 later in the season and remained all the winter. The 

 birds became so reduced in flesh that after every 

 cold rain or severe frost numbers were found dead 

 under the trees where they roosted ; and in that 

 way most of them perished before the return of 

 spring. 



