154 THE STORY OF BIRD-LIFE. 



layer, as in the cuckoos known as the guira and 

 the ani ; or in the rosy flamingo and our British 

 Sclavonian grebe. In the ani, if this layer be re- 

 moved, the shell beneath will be found to be of 

 a, brilliant blue colour. In the ostrich and emu 

 and some others the surface is deeply pitted. 



The condition of the young when hatched 

 depends largely upon the relative size of the 

 egg. Thus in birds which lay small eggs the 

 young are, at birth, blind and helpless; when 

 the egg is relatively large the young will be 

 found to be very active within a short time 

 after birth, and able to feed themselves. The 

 former group of birds build more or less 

 elaborately constructed nests, the latter little 

 or none. This ratio between the size of the 

 egg and the condition of the chick at birth has 

 caused a great disproportion in the relative 

 size of the egg and the bird which produces it. 

 Thus the guillemot and the raven are birds of 

 equal size, yet their eggs vary as ten to one, the 

 egg of the guillemot being relatively huge, and 

 as large as that of an eagle. 



The smallest egg of living birds is that of the 

 humming-bird, the largest that of the ostrich. 

 The largest known bird's egg is that of the ex- 

 tinct ^Epyornis of Madagascar. An egg of the 

 latter is often found in the lap of the skeleton of 

 some chief, as though placed there to afford the 

 spirit sustenance on its long journey to the other 

 world, the custom of providing the dead with 

 food and even raiment and weapons being a very 

 wide one amongst primitive people. The girth of 

 this egg is about thirty inches, its longest circum- 



