2 24 Habit and Instinct. 



Nature." * " The finest of the Platan rails," he says, " is 

 the ypecaha, a beautiful active bird about the size of a 

 fowl. A number of the rails have their assembling-place 

 on a small area of smooth, level ground just above the 

 water, and hemmed in by dense rush beds. First one bird 

 among the rushes emits a powerful cry, thrice repeated ; 

 and this is a note of invitation, quickly responded to by 

 other birds from all sides as they hurriedly repair to the 

 usual place. In a few moments they appear to the 

 number of a dozen or twenty, bursting from the rushes 

 and running into the open space, and instantly beginning 

 the performance. This is a tremendous screaming concert. 

 The screams they utter have a certain resemblance to the 

 human voice, exerted to its utmost pitch and expressive of 

 extreme terror, frenzy, and despair. A long piercing 

 shriek, astonishing for its vehemence and power, is suc- 

 ceeded by a lower note, as if in the first the creature 

 had well-nigh exhausted itself; this double scream is 

 repeated several times, and followed by other sounds, 

 resembling, as they rise and fall, half-smothered cries of 

 pain and moans of anguish. Suddenly the unearthly 

 shrieks are renewed in all their power. While screaming 

 the birds rush from side to side, as if possessed with mad- 

 ness, the wings spread and vibrating, the long beak wide open 

 and raised vertically. This exhibition lasts three or four 

 minutes, after which the assembly peacefully breaks up." 



Mr. Hudson also describes a somewhat similar perform- 

 ance of the wattled, wing-spurred, and long-toed jacana, 

 a performance which seems specially designed to bring out 

 the concealed beauty of the silky, greenish-golden wing- 

 quills ; and he has an inimitable paragraph on the strange 

 visits and dances of the spur-winged plovers. Here the 

 male bird leaving his mate pays a call on a neighbouring 



' " Naturalist in La Plata," p. 266. 



