130 THE UNIVERSITY OF THE STATE OF NEW YORK 



b Normal, 4 or 5 



Chestnut-sided warbler 

 Catbird 



c Large 



Grouse, IS eggs 

 Mallard, 9 eggs; 10 eggs 



Game birds lay from eight to. twenty eggs. 



2 Size 



a Actual 



The eggs vary in size from those of the hummingbird to those 

 of the ostrich. For eggs of the hummingbird, see Nu HuR2; 

 for those of the ostrich, see Cv Y3, List 38, p. 10. 



b Relative to the bird 



Catbird and Spotted Sandpiper; an Egg of 

 Each. Specimens, New York State Mu- 

 seum. (1919) Nu Cd3 



Birds which have precocial young lay relatively larger eggs 

 than those which have altricial young, because the embryos are 

 nourished longer within the egg. Compare the relative size of 

 the eggs and the birds in the catbird and the spotted sandpiper, 

 birds of approximately the same size. 



3 Color 



The nest is most conspicuous when the eggs lie in it uncov- 

 ered, that is, previous to the beginning of incubation. If the 

 eggs pass though this period safely, they have a good chance of 

 being hatched. Birds building no nest at all usually lay very 

 protectively colored eggs and have protectively colored young 

 but those building bulky, conspicuous nests likewise have con- 

 spicuous eggs and rely upon the inaccessibility of the nesting 

 site or upon concealment of the whole structure to protect them. 



o Protectively colored 



Killdeer Nu Ke3 



Night hawk Nu Ni2 



Caspian tern Nu TfC2 



b Conspicuous eggs 



Wood pewee Nu Pi2 



Black-crowned night heron Nu HeB3 



Green heron Nu HeH2 



