\ii COLORATION OF EGGS 323 



fact that different species have different nesting 

 habits. The eggs of the Raven, Crow, Rook, and 

 Jackdaw are by no means unlike in colour. The 

 Gulls arc nearly allied to the Plovers, Curlews, Ruffs, 

 Sand-pipers, and Avocets ; and this fact, probably, 

 supplies the explanation of the supposed protective 

 colouring in the case of Gulls' eggs, which require 

 no protection. In the same way we can account for 

 the white eggs of the Short-eared Owl. Occasionally 

 we find a species whose eggs are differently coloured 

 from those of its allies, without there being any 

 difference of nesting habit to explain it. The Little 

 Bittern, for instance, lays eggs of a dull white, while 

 those of other Bitterns are of a brownish olive colour. 

 It seems, in fact, that Natural Selection does not 

 work either universally or very promptly upon the 

 colours of eggs. If the Wood Pigeon's eggs were of 

 an inconspicuous tint, it might be a slight gain to the 

 species. But the birds are so vigorous, so strong on 

 the wing, and so able to find food, that a slight imper- 

 fection such as the whiteness of their eggs does not 

 materially reduce their numbers. The large number 

 of eggs laid by the common chicken may allow for 

 thc destruction of a good many nests, so that con- 

 cealment can be dispensed with. And it must also 

 be borne in mind that when a bird lays only one or 

 two eggs, sitting begins soon, so that there is more 

 need for the concealment of the birds than the eggs. 

 Though it may seem a paradox to say so, it is some- 

 times because the eggs arc many and sometimes 

 because they are few that protective colouring is 

 unnecessary. 



Y 2 



