ANIMAL MIGRATIONS 379 



the grey of the evening and morning, is one of the 

 first things that strikes the attention of the voyager 

 on the Amazon. 



The periodical appearance of certain birds in a 

 district has been supposed by the inhabitants to 

 have some mysterious connection with the Christian 

 festivals. Thus there are two beautiful little birds 

 in Maynas, apparently belonging to different genera, 

 for one of them is a Seven-coloured Tanao-er 



o 



(Pajaro de siete colores), and the other (which I 

 have not seen) is said to be of a bright blue colour 

 and differently shaped ; but both are called by the 

 Indians Huata-pisco (Bird of the Year), because 

 they make their appearance together, in large 

 flocks, about the end of the year (people will tell 

 you, precisely on Christmas Day), and remain 

 throughout January, when they are seen no more 

 until the same epoch comes round again. Mr. 

 Bates has given a capital account of the movements 

 of these hunting-parties of frugivorous and insec- 

 tivorous birds, and of the superstition of the Papa- 

 uira or Patriarch Bird, who is supposed to head 

 them (vol. ii. p. 333 et seq.\ I suspect that this is 

 something more than mere superstition, and that 

 the Patriarch leaders are not one but several to 

 each predatory band. 



DISTRIBUTION OF FISHES 



The abundance of fish in rivers of white water, 

 and their scarcity in black-water rivers, may easily 

 be shown to depend chiefly on the luxuriant littoral 

 vegetation of the former and its scarcity or utter 

 absence in the latter ; for on the Rio Negro there 



