THE NATURAL HISTORY OF NESTS 



level of nest-making, but their depression is lined 

 with down. The ringed plover lays its eggs on 

 the shingle, where they are so like rounded pebbles 

 that they are most effectively lost to ordinary 

 vision. One of the most charming of ground nests 

 is that of the eider-duck, where a thick quilt of 

 down is accumulated that can be drawn over the 

 eggs when the mother-bird goes down to the sea for 

 food. 



In not a few birds the only care is to bury the 

 eggs a way of securing their safety that recalls 

 suggestively the habits of some reptiles, such as 

 crocodiles, which are historically antecedent to 

 birds. The New Zealand kiwi puts its single big 

 egg in a hollow at the base of a tree-fern ; the female 

 ostrich lays her eggs in a hole which the cock scrapes 

 in the sand, and both birds share in brooding. 

 Some mound-birds bury their eggs in the sand and 

 leave them, while others heap a huge hot-bed of 

 dead leaves over the spot. 



Grebes and some rails collect pieces of water- 

 plants and " form of them a rude half -floating 

 mass, which is piled on some growing water-weed " ; 

 and while they do not shirk incubation, they seem 

 to trust partly to the heat of decomposition. 



We gradually work up from ground-nests to the 

 earth-mounds on which the flamingos sit, and on 

 to rough platforms like that of the wood-pigeon, 

 through the floor of which the eggs may be seen 

 from below. Making a fresh start, we reach the 

 more elaborate stick nests of the rooks and crows ; 

 from these we pass to the heron's, where a little 



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