Recognition Colours 



to India, where they are replaced as residents by 

 the Shaheen (Falco peregrinator) and Indian 

 Hobby (F. severus). Both these differ from the 

 migratory forms by being blacker above and 

 chestnut below, instead of cream colour. Thus 

 the resemblance occurs in each race. A similar 

 distinction, as noted by Blyth, exists between 

 the Common Swallow (Hzrundo rustica) and the 

 Swallow (H. tytleri) of Eastern Asia, the latter 

 having the whole ventral surface rufous instead 

 of only the throat. Yet no one will suggest that 

 swallows mimic falcons, or that there is mimicry 

 between the peregrine and hobby. It is obvious 

 that such parallel changes occur independently 

 of mimicry. 



The Water-rail (Rallus aquaticus) and Baillon's 

 Crake (Porzana bailloni) of Europe are distin- 

 guished from their allies of Eastern Asia by 

 having the sides of the head plain grey, whereas 

 the Eastern Asiatic forms (R. indicus and P. 

 pusilla) have a brown streak along each side of 

 the face. Here, again, we have an instance of 

 birds of the same family varying together with 

 geographical distribution. 



" RECOGNITION " COLOURS 



One of the prettiest conceits of the Wallaceian 

 school of zoologists is the theory of recognition 

 markings. 



" If," writes Wallace, on page 2 1 7 of Darwinism, 

 251 



