2IO GLIMPSES OF INDIAN BIRDS 



white, to fawn colour. The markings sometimes 

 take the form of blotches, so that the eggs look like 

 those of a small tern. More usually the markings 

 appear as tiny spots, freckles, pencillings, or cloudy 

 smudges. On a sandbank containing twenty nests it 

 is possible to pick out ten eggs, each of which differs 

 so greatly from the others that the casual observer 

 would certainly say they aU belonged to different 

 species. The size is, of course, fairly uniform, but the 

 shape varies greatly ; some are elongated, while others 

 are nearly as broad as they are long. Occasionally 

 a pear-shaped egg is found, but as a rule the narrow 

 end of the egg is comparatively blunt. That eggs 

 which are laid on the sand in the open should display 

 these extraordinary variations is an awkward fact 

 for those who consider that the colouring of birds' 

 eggs is the direct result of natural selection. If this 

 were so we should expect to find a wonderful sameness 

 about the eggs of this species, which are laid in such 

 exposed situations. The fact is, of course, that on a 

 sandbank eggs of any colour that is not too pro- 

 nounced are difficult to see ; hence, for purposes of 

 protection, the actual colours of the background and 

 the markings of the egg are matters of little im- 

 portance. 



