104 THE INFANCY OF ANIMALS 



Every whit as puzzling are the phenomena presented 

 by the birds, both of the precocious and helpless types, 

 wherein the coloration is of one uniform hue, either white, 

 dark grey, or brown. In the birds of prey, the owls, the 

 swans, the storks, and some Passerine birds — that is to 

 say, among birds not even remotely related, and which 

 are reared in totally unlike surroundings — the downy 

 cloak is white. In the cormorant the youngster is 

 enveloped in a mantle of dark brown, in the gannet at 

 the same age, and reared within a few feet of the same 

 spot, it is pure white. Young petrels reared in holes 

 wear a sombre cloak of brown or slate colour, where one 

 might expect to find a mantle of white, such as is worn 

 by the young albatross reared in the open. Similarly, 

 young penguins, whether lying under a burning sun, as 

 in the case of the Cape penguin (Spheniscus demersus), or 

 crouching low on an Antarctic ice-field, as in that of the 

 King penguin, are dark brown ; but the young of the 

 Emperor penguin, as befits him, wear an ermine robe, 

 relieved by a black mask. 



Are we to regard the loss of the pattern in such cases 

 as due to the cessation of natural selection ? But if so, 

 why do we meet with a pigmented down in some cases 

 and a colourless down in others f The loss of patterns 

 in the down of such nestlings confirms the contention 

 that such patterns are useful when they obtain. In other 

 words, if the patterns, stripes, or mottlings are for con- 

 cealment, such devices would be useless in birds confined 

 in nests — for the latter are often conspicuous objects, 

 and predatory animals well know the nature of their 

 contents. That the down of nidicolous birds which are 

 reared in exposed situations — such as the ledges of cliffs, 

 as in the case of the auk tribe, cormorants, and gannets 



