Home Life 



so 



like the heron, kingfisher, woodpecker, robin, 

 and all our song birds. The precocial ruffed grouse 

 develops from an egg that is large in proportion to 

 the size of the mother's body, the heavy yolk 

 nourishing the young bird during eighteen days of 



Blind, naked and helpless altricials. Young blue-birds 



incubation and even after, whereas the altricial vireo 

 lays a very small egg that hatches in one week. But 

 even precocial and altricial birds of the same size 

 in maturity may have come out of shells that differ 

 as greatly as a silver dollar differs from a quarter. 

 And the length of the period of incubation is in 

 nearly, if not exact, ratio to the size of the egg. 

 The largest bird's egg we know, the ostrich's, re- 



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