CHAPTER XII 



COLORATION OF EGGS 



The eggs of reptiles are white, and the reptilian 

 origin of birds would lead us to the conclusion that the 

 eggs of primitive birds were like them. But the eggs 

 of existing birds present a great variety of colours, 

 though it is seldom that very bright tints are found, 

 and the question is how these colours are to be 

 accounted for. There can hardly be a doubt that 

 the coloration is in some cases protective, but we 

 must be careful not to extend this explanation too 

 far. Dr. Wallace has pointed out that a very 

 large proportion of the eggs that are white or light- 

 coloured enough to be conspicuous are found in 

 domed nests or nests built in holes, so that they 

 cannot be seen. For instance. Kingfishers and Puffins 

 nest in holes in the ground ; Woodpeckers. Hoopoes, 

 and Owls in holes in trees ; Wrens and the Willow- 

 warblers build domed nests. Ducks and Grebes lay 

 their pale eggs in open nests, but they have the habit 

 of covering them up : these exceptions are, therefore, 

 a very first-rate illustration of the principle. There 



