444 ^^^ ^''"^ 



species is exposed. I believe that this factor is fairly 

 constant for species or tribes of similar habits, and that 

 exceptions indicate peculiarities of circumstances which 

 in many cases we can easily perceive, because I believe 

 that Nature is strictly economical of energy, allowing 

 no more eggs to be laid, and consequently young to be 

 produced, than the conditions justify in each case. Thus 

 the uniformity of avine population — the balance of bird- 

 life — is maintained." 



When a bird's nest and eggs are destro3^ed, she will 

 often lay another setting, and some birds raise two and 

 even three broods in a season under normal conditions. 

 If the eggs of a bird are removed as fast as they are laid, 

 the bird will sometimes continue to lay, one of the most 

 remarkable instances of this in an uncaged bird being 

 a Flicker which laid seventy-one eggs during the space 

 of three-and-seventy days. A tiny African Waxbill in 

 captivity has been known to rear fifty-four young in the 

 course of a year, during the same period laying an addi- 

 tional sixty-seven eggs! The domestic hen has become 

 a veritable egg-laying machine, thanks to careful breed- 

 ing in the past, since the wild Red Jungle Fowl from which 

 all varieties of poultry are descended, lays only one nestful 

 of seven to twelve eggs once a year. 



Many birds still hold to the old style of nesting in 

 hollow trees and such concealed places. Whether they 

 hunt around until they find a cavity ready-made by the 

 elements, or whether, like the woodpeckers, they pro- 

 ceed to excavate a home in a dead branch, or, kingfisher- 

 like, to tunnel deep into a sand-bank, their eggs are almost 



