THE PLAY OP ANIMALS. 211 



in a frightful concert that made the whole house trem- 

 ble. Brehm says: "Lions in the wilderness, too, de- 

 light in this; as soon as one lifts up his mighty voice 

 all others within hearing join him, making magnificent 

 music in the primeval forest." Most remarkable are 

 the concerts of howling apes, whose din fills the South 

 American wilderness; with them, too, a solitary voice 

 is heard at first which incites the rest to accompany 

 the leader. I believe this is a phenomenon of courtship, 

 like the nocturnal wailings of cats. 



Imitation seems to be even more provocative of con- 

 certs among the birds. I included under experimenta- 

 tion descriptions of the chakar, of the familiar cries 

 and gabbling of geese, ducks, and crows, and of the 

 myriad-voiced concerts of our woodland singers which 

 mutually incite one another. I cite a description of 

 Hudson's which might apply to many birds that de- 

 light our eyes by their evolutions in flight. " In clear 

 weather they often rise to a great height and float for 

 hours in the same neighbourhood — a beautiful cloud of 

 birds that does not change its form, . . . but in this 

 apparent vagueness there is perfect order, and among 

 all those hundreds of swiftly gliding forms each knows 

 its place so well that no two ever touch; . . . there is 

 such wonderful precision in the endless curves made 

 by each single bird that an observer can lie on his back 

 for an hour watching this mysterious cloud dance in 

 the open without tiring." 



The black-headed ibis of Patagonia, which is almost 

 as large as a turkey, carries on a strange wild game 

 in the evening. A whole flock seems to be suddenly 

 crazed; sometimes they fly up into the air with startling 

 suddenness, move about in a most erratic way, and as 

 they near the ground start up again and so repeat the 



