146 FAMILIAR WILD BIRDS. 



Take, for example, the egg of the Guillemot. This is so 

 wonderfully constructed, that if moved it will not roll 

 away, like a marble or billiard-ball, but simply spin round 

 on its axis, the same as a screw or top, showing admirable 

 adaptability to the exposed situation chosen by this bird for 

 incubation. 



Birds that build their nests in holes, such as the Owl, 

 for instance, lay round eggs, which run no risk of being 

 rolled about and smashed. Were the Owl and Guillemot 

 to change positions for a while, the latter would stand a 

 fair chance of speedy extermination, affording a beauti- 

 ful illustration of the profound wisdom which has been 

 brought to bear in the working out of the grand problem 

 of preservation. 



As a further illustration, let us take the eggs of the 

 Golden or Green Plover, and consider for a minute their 

 shape, number, and colour. In the first place, like that of 

 the Guillemot, they are laid on an almost flat surface in 

 bleak moorland districts, often on the summit of a little 

 knoll, to preserve them from being swamped by heavy 

 rains. In the second place, they are very large eggs for 

 the size of the bird. How wisely this difficulty is met 

 and surmounted ; for all their sharp points meet in the 

 centre, and practically form a square, so that the bird may 

 be enabled to cover them all at the same time ; whereas, if 

 she laid five eggs it would be a matter almost impossible 

 for her to hatch them all successfully. He who is curious 

 enough to turn the round end of a Plover's egg into the 

 centre of the nest, and walk away a respectful distance, 

 will find on his return the parent bird has discovered the 

 chaos in her little household, and speedily set matters right 

 again. In the third place, the beautiful harmony of 



