i8o BIRDS OF LA PLATA 



prey generally. Its noisy cry and irascible temper 



are spoken of by most travellers and naturalists; 



for no person riding across the pampas could possibly 



overlook the bird, with its screaming protests against 



all trespassers perpetually ringing in his ears ; but 



they have all omitted to mention the singular habit 



which this bird has of associating in sets of three 



for the purpose of amusement or play. Each couple, 



as I have said, live always together on their own 



pretty well - defined plot of ground, which they 



jealously guard from intrusion. Yet if you watch 



a pair of them for a while you will presently see 



another bird — one of a neighbouring couple — rise 



up and fly to them, leaving his own mate to take care 



of home ; and instead of resenting this visit as an 



intrusion, they welcome it with notes and signs of 



manifest pleasure. Advancing to the visitor, they 



place themselves behind it, and then all three, keeping 



step, begin a rapid march, uttering loud drumming 



and rhythmical notes in time with their movements, 



the notes of the birds behind coming in a rapid 



stream, while the leading bird utters loud single notes 



at regular intervals. The march ceases, the leader 



stretches out his wings, still emitting loud notes, 



while the other two, with puffed-out plumage, 



standing exactly abreast, stoop forward until the 



tips of their beaks touch the ground, and, sinking 



their voices to a murmur, remain for some time in 



this singular posture. The performance is then over ; 



the birds all resume their natural attitudes, and the 



visitor takes his leave. It is quite certain that this 



