1903 Notes on the Nests and Eggs of Birds 201 



Notes on the Nests and Eggs of Birds. 



By Rev. M. C. H. Bird. 

 {Continued from p. 137.) 



We come now to the most fascinating diversity of color- 

 ation : what is its explanation, and upon what does the 

 special colouring of eggs depend ? Primarily upon the 

 species ; secondly, upon the situation and architecture of 

 the nest ; thirdly, upon the health of the parent bird ; but 

 food {pace Pycraft on the Shrike, Bird Life, p. 164) has 

 little or no influence, as anybody may easily prove by ex- 

 periment with two barn-door hens, one of the brown, the 

 other of the white egg-laying type. For much variation in 

 the texture of egg-shells we should have to go to foreign 

 birds to find extreme examples, but they may be typified 

 amongst local breeders as being extremely smooth in the 

 pheasant, smooth and glossy in the kingfisher, dull and 

 chalky in the grebe, and pitted in the case of the French 

 partridge. The colour of an egg has no reference to that 

 of parent bird or chick, but in domestic poultry tinted 

 eggs are chiefly laid by fowls with dark plumage or 

 yellow skin. 



White was probably the primitive colour of the eggs of 

 all birds, as it still is practically of all reptiles. The con- 

 spicuous white was originally hidden by the eggs of reptiles 

 being buried, or dirtied by the parents' feet ; and so we still 

 find that, where possible, the eggs of all birds are covered 

 with a plain white shell, superficial shades and markings 

 being only added for protective purposes. Where eggs are 

 laid out of sight in holes in the earth or in hollow trees or 

 in crevices, entirely concealed from the light, and where the 

 parent bird makes an open nest and feeds nocturnally, there 

 the eggs are also mostly white, or at anyratc of a very pale 

 tint. So clean are the eggs of the great crested grebe when 

 first laid that anyone who had only seen those of this 

 species which had been for a day or two in contact with 

 the rotting vegetation of which the nest is composed would 



