Coloration of the Mouths and Eggs of Birds. 287 



sufficiently account for most of them ; but they are likely- 

 enough to be useful in "reminding" enemies, and I am 

 inclined to think that there is quite a mnemonic element in 

 some of these calls and displays. I am unable to refrain 

 from quoting Mr. Bates' description of the behaviour of five 

 young Kingfishers, Alcedo guentheri {' Ibis/ 1911, p. 515): — 

 '' While they remained alive for a few hours in a box, one 

 of them continually made a most curious noise, something 

 between a rattle and a fizzle, rhythmically varied in loudness 

 by the opening and closing of the bill. Only one bird did 

 this, and always the same one, while the rest remained 

 silent. When that one was removed another, after some 

 minutes, took up the role of ' soda-water bottle,' and when 

 that one was removed another commenced. There was 

 always one ' fizzler' only.'^ 



In the external appearance of nestlings one also comes 

 across many instances of moderate and a few of strong, even 

 conspicuous, distinctiveness. Such are the special orna- 

 ments of the young Coot and Great Crested Grebe; the 

 extraordinary general appearance of the nestling of the 

 Lark-heeled Cuckoo, Centropus hurchelli, quite black with 

 sparse thread-like hairs of purest white (the down feathers) 

 all over the upper surface ; and, Mr. Wallis suggests, " the 

 intense hairy blackness of the nestling in down of the 

 Water- Rail. This is so conspicuous that it must have a 

 cause, for it is not protective as is the mai'king of the Snipe 

 in down." He goes on to mention its "fair^^ resemblance 

 to "the larva o£ the Cream-spot Tiger-moth, which feeds 

 on comfrey in the same marsh"*. 



* It is interesting to quote the rest of the passage : — " The half-grown 

 Lapwing, just when his back is getting green, but whilst tufts of down 

 are still on him, is a most repulsive object. He lies about openly among 

 the cows in a pasture and mimics a mass of wet, green excrement in 

 which the mould is beginning to sprout, so exactly that nineteen people 

 out of twenty would not touch him. Of course you know the immense 

 yellow gape of the nestling Cuckoo, and his toad-like appearance. 



Country children have been afraid to touch one You know the 



intense, hairy blackness, &c," 



