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 day 
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. 
