Birds' Eggs 



With their sizes and shapes we are not concerned ; it is 

 their colours alone that interest us for the moment. The 

 one, a neat little egg, is dark cream in colour, spotted 

 with grey and brown ; the other is not altogether dis- 

 similar, but the fine spots are wanting and in their place 

 we observe large, bold blotches. We have been told, and 

 rightly so, that both these birds nest upon the seashore. 

 How, we may well ask, can eggs so diverse in general 

 markings both be protected by their colour ? 



Let us place the first egg, the one with the fine dots, on 

 the fine sand and observe that it is most difficult to isolate 

 it from its surroundings. The ringed plover, which laid 

 the egg, always selects fine sand for its nest. Now let us 

 take the other egg, the boldly marked one, higher up on 

 the shore, almost to the line where sand and shingle meet, 

 where a miscellaneous collection of the leavings of the sea 

 lie scattered here and there. Let us place our egg on this 

 ground and notice that it is even more difficult to find 

 than the other. The second egg belongs to the lesser 

 tern, which nests where sand and shingle meet. 



In almost every species of bird there is a reason for the 

 colour or shape of its eggs. We could quote example after 

 example of eggs designed to harmonise with their usual 

 surroundings. Hawks' eggs usually resemble the lining 

 of the nest, and the eggs of the common house-sparrow 

 harmonise so well with the feathers with which it upholsters 

 its nest that they are by no means easy to detect. 

 Occasionally, however, some foolish bird will build its 

 nest in such a position that its eggs by their very colour 

 and markings are rendered conspicuous. What is the 

 result of such daring ? Calamity befalls the home in the 

 majority of cases and the law of the survival of the fittest 

 holds sway. Foolish birds are not encouraged by Nature 

 to beget other foolish birds. 



It is often difficult to account for the colouring of eggs ; 

 we have mentioned a few of these puzzling cases already. 

 The common guillemot lays but a single egg each year, 



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