42 BIRDS. 



run and feed themselves as soon as hatched, the eggs are large. Such hirds usually 

 lay on the ground in imperfectly formed nests. Other circumstances seem to 

 influence the size of the egg in some cases. Thus the Cuckoo, which lays its 

 eggs in the nests of hirds much smaller than itself, has eggs of size nearly corre- 

 sponding to theirs, and therefore relatively the smallest of any of the class. 



Among birds of about equal size with different-sized eggs are the Guillemot, 

 the Curlew, and the Eaven, where their eggs are as 3-2" x 2", 2-6" x 1-8", and 

 2" X 1-3" respectively. The Snipe is about the same size as a Blackbird, and yet 

 its egg is J" longer and J" wider. The Apteryx has a far larger egg than the 

 Crowned Pigeon, while Cuckoos' eggs are but slightly larger than those of a 

 House Sparrow. The smallest eggs are those of some species of Humming 

 Birds. Of existing birds, the Ostrich lays the largest egg, but these were far 

 exceeded by those of the extinct .^yornis of Madagascar. 



Texture of surface. The surface of the shell of the eggs of different birds 

 varies much in texture. It may be — 



{A) Extremely smooth and polished, as with Tinamous. 

 {B) Smooth and glossy, as in the Woodpecker, Kingfisher. 

 ((7) Dull and chalky, as in the Ibis, Megapode, Duck. 



{D) Covered with a distinct calcareous film, sometimes of considerable and 

 irregular thickness, as in the Shag, Grebe, Flamingo. 

 (E) Distinctly granulated or pitted, as in the Emeu. 



Colour. The colour of the egg has no relation to that of the parent bird. 

 White is probably the primitive colour of birds' eggs, as it is that of the eggs of 

 all reptiles. The eggs birds laid in holes, either in the earth or in trees, 

 entirely concealed from the light, are mostly white (exceptions — Nuthatch, Tree- 

 Creeper, Jackdaw). The largest number of eggs are variously coloured by the 

 deposition of pigment on or near the outer surface of the shell. The colour may 

 be uniform throughout the surface of the shell, or it may be in irregular washes, 

 blotches more or less circular, spots or lines upon either a white or uniformly 

 coloured ground. Examples : — 



One colour. Tinamous, Virginian Colin, Owl, Grey Parrot, Bee-Eater, Wryneck, 

 Woodpecker, KoUer, Stork, Swan, Wild Duck, Francolin, Pheasant, Jagand, 

 Warblers, Nightingale, Fly-Catcher, Redstart, Indian Minah, Jay, Thrush, Heron, 

 Ibis. 



Clouded. Godwit, Peregrine Falcon. 



Blotched. Sparrow-Hawk, Sandwich Tern, Razorbill, Ptarmigan, Red Grouse. 



Speckled, Red-legged Partridge, Jay, Carrion Crow. 



Spotted. Hemipode, Pratincole, Diver, Sandpiper, Redshank, Golden Oriole, 

 Wren Warbler, Willow Warbler, Tit, Song Thrush, Swift, Tern, Oyster-Catcher, 

 Sand-Grouse. 



With linear markings. Starling, Crow, Blackbird, Guillemot, Indian Jagana. 



The signification of the various modes of colouration is very little understood 

 at present. It often happens that the different species of a natural group of 

 birds present a general similarity in the style of colouration "of their eggs, or, in 

 other words, that nearly allied birds have similar eggs, but the exceptions to this 

 rule are very numerous. In certain cases there is evidently an adaptation of the 



