Mimicry in Birds 



resemblance ; thus the common fowl often ex- 

 hibits a variety in which the body is white and 

 the primary quills and tail black, a coloration very 

 characteristic of many large and powerful birds. 



Applying this to the stock case of the orioles, 

 we may compare the hypothetical ancestor of 

 these birds with the known canary. This bird 

 is normally, in its wild state (and often in domes- 

 tication), of a streaky olive-green, somewhat like 

 the young of many orioles; it frequently produces 

 a cinnamon form, and (very rarely) a brown one, 

 which may be compared to the mimicking orioles, 

 and every one knows its yellow and pied varia- 

 tions, one of which, the nearly-extinct " London 

 Fancy " breed, has dark quills and tail, and so 

 very closely approaches the golden oriole's plan 

 of coloration. 



Now there is one oriole, the Australian Oriolus 

 viridis, which is throughout life green and 

 streaky, and may be taken as representing the 

 ancestor ; and this shows not the slightest re- 

 semblance to the common Australian friar-bird 

 (Tropidorhynchus corniculatus), which has the 

 usual snuffy-brown of his relatives, and a head 

 altogether bald and black ; in fact he is the 

 typical friar. 



He is evidently a hopeless model for the green 

 oriole, although as warlike, and therefore as de- 

 sirable in that capacity, as the insular members 



65 E 



