46 ] How to Understand the Birds 



THE SIZE OF EGGS 



"Which bird lays the biggest eggs?" and "Which lays the 

 smallest?" are welcome questions because we have direct and 

 definite answers to them. The ostrich, largest of birds, lays the 

 largest eggs; the hummingbird, smallest of birds, lays the smallest 



eggs. 



However, it does not always follow that the larger bird lays 

 the larger egg. A bird whose chicks come forth in a well-developed 

 state, lays relatively larger eggs than a bird whose chicks are less 

 well developed. 



Among the well-developed babies are those of our friend the 

 chicken, the grouse, and the spotted sandpiper. When they hatch 

 they are already covered with a soft down. Their eyes open imme- 

 diately and in no time at all they can toddle about and follow 

 their mother. Before long they learn to pick up and eat their own 

 food. We term this kind of bird "precocial," a word related to 

 "precocious." Birds that hatch in a more helpless state are naked 

 or at best have a scant covering of down. They are blind at first 

 and are dependent on their parents for at least a week usually 

 much longer. Such birds are known as "altricial," from the Latin 

 word for "nourishers." 



"BABY SITTERS" 



The length of time needed for incubation varies with dif- 

 ferent species. The English sparrow takes twelve or thirteen days; 

 the robin, thirteen or fourteen days; the fish hawk, about four 

 weeks. In some families the duty of sitting on the eggs is shared 

 by both parents; in others, it falls entirely to the lot of the mother. 

 There is one curious family in which the eggs, once they have 

 been laid by the female, become the sole responsibility of the 

 male. He incubates the eggs unaided, though the mother stays 

 nearby and shows continued interest in her family. These birds 

 are the phalaropes, found in many parts of North America. 



BRINGING UP BABY 



Helpless baby birds require an extraordinary amount of 

 care, and perhaps because it helps to build in themselves a sense 



