In defence of its territory it wages perpetual war against most living creatures, the objects of its special abhorrence being men, dogs, rheas, and birds of 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 one watches a pair of them for a while he presently sees another--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 display has no connection with the sexual feeling, for it is indulged in all the year round, at all hours of the day, and also during moonlight nights. It is simply the bird's manner of expressing its joyous spirits; for most living creatures--birds especially--have more or less well-defined methods of playing; and playday with the Téru is every day, and at very brief intervals. And yet the grave pompous air of the birds, and the military precision of their movements, might easily lead an observer to attribute these displays to some more important motive. Play is not only indulged in with neighbours; there are many solitary Térus continually wandering about from place to place--probably young birds not yet settled in life--and when one of these vagrants passes near a pair he is immediately invited to join them, and, when he alights, all go through the performance together with great zest. In this case, however, as soon as it is over, the strange bird is attacked with great spirit and chased away; and if by chance he comes down again near them, they hasten to drive him up with increased fury.