GREEN PIGEONS 129 



lady love and in this attitude move his expanded tail 

 up and down. 



There are few birds that assimilate so closely to 

 their surroundings as green pigeons. Fifty of them 

 may be perched in a pipal tree, and a man on the look- 

 out for them may fail to detect a single individual 

 until one of the birds moves. They are thus excellent 

 examples of protectively coloured birds. Their green 

 livery undoubtedly affords them a certain amount 

 of protection, and so may perhaps be considered a 

 product of natural selection. Be this as it may, 

 a consideration of the details of the colouring of their 

 plumage shows that many of these, as, for example, 

 the lilac on the wing, are quite unnecessary for the 

 concealment of the bird. The eastern and the southern 

 species which occur together in certain places and the 

 hybrids produced by the interbreeding of these are 

 all equally difficult to distinguish from the surrounding 

 leaves, notwithstanding the fact that their plumage 

 differs in details, e.g. the breast and the abdomen 

 are greenish yellow in the southern and ashy-grey in 

 the eastern form, while there is green in the fore- 

 head and tail of the latter, but not of the former. 

 Thus we have two species of green pigeon, of which 

 at least one has not originated by natural selection. 

 Facts such as these, however, do not prevent Dr. 

 Wallace, Sir E. Ray Lankester, and Professor Poulton 

 continually proclaiming from the housetops that 

 every existing species owes its origin to natural se- 

 lection and nothing but natural selection ! 



There are several genera of green pigeons, and all of 



K 



