THE UNCHARTED SKY 121 



*'It's endurance," agreed the pot-hunter, ^'but 

 it's jest foolishness, too. There ain't nothin' to 

 keep her from waitin' till spring, leastways, not 

 so far as I can see." 



''Nothing," the expert agreed, ''only the Pen- 

 guin doesn't migrate far." 



"You spoke about birds on the other side of the 

 equator and in hot countries that don't migrate," 

 said the boy; "how do they manage?" 



"In hot countries," the expert answered, "in- 

 cubation sometimes plays some very strange tricks. 

 The Ostrich, the Rhea, the Emu, and other birds 

 of that Order allow their eggs to hatch by the heat 

 of the sun, and the male bird sits on them at night 

 only to keep off egg thieves. Meantime, the hen- 

 birds stand around and watch him. 



"There are birds which make incubators for 

 themselves. The Australian Brush-Turkeys build 

 heaps of damp vegetable material and lay their 

 eggs in those, depending on the heat produced by 

 the fermentation of the rotting vegetation to hatch 

 the eggs. The Ocellated Megapode does much the 

 same thing, but uses the rotting vegetation merely 

 as a stove and spreads a layer of sand over the 

 heating heap, laying her eggs on this. The Maleo, 

 a bird living in the island of Celebes, lays her eggs 



