14 EGGS AND EGG-COLLECTING. 



Thirdly, the number of eggs is always four, and by 

 such limitation the form of the square is preserved, 

 and the difficulty of a small bird covering a number of 

 large eggs satisfactorily surmounted. I have often dis- 

 arranged the order of Plovers' eggs, but always found that 

 the first thing done by the bird on her return was to 

 reduce chaos to order by turning the round ends out and 

 the small ones into the centre of her little household. 



Lastly, we come to the beautiful harmony of colouring 

 of the eggs with surrounding objects, rendering them often 

 very difficult to find, even by a practised eye, and the 

 scant nest still further aiding in the chances against dis- 

 covery. 



The Sandpiper affords an admirable instance of the 

 assimilation of its eggs to surrounding objects, and the 

 extreme difiiculty experienced in finding them attests to 

 its protective utility. 



Why Eggs Vary so much in Point of Number, — 

 The jiumber of eggs laid by birds of different orders 

 seems to be regulated by the danger to which they are 

 exposed and the amount of food which the parents will be 

 able to supply. 



Thus, the Eagle in its inaccessible eyrie enjoys almost 

 perfect immunity from danger, and has only two young 

 ones, for which, however, the supply of food is only equal 

 to the demand, and it is probable that one more voracious 

 appetite would seriously endanger the safety of the whole 

 family. 



On the other hand, take the Common Partridge with 

 its sixteen or twenty eggs, the high percentage of its 

 dangers, and the generally abundant supply of food. 



Again, the Swift, on its untiring wings for sixteen 



