230 THE LIFE OF A BIRD. 



the thermometer fell again. Now, although the 

 temperature of 71 or 72 of Fahrenheit's ther- 

 mometer is not sufficiently great to favour the 

 development of the germs in the eggs, yet the bird 

 evidently perceived that the eggs would suffer no 

 injury during her absence while the temperature 

 was at this point, and seems to have availed her- 

 self of the opportunity to fly in search of food. 

 Mr. Jesse continues : " This fact leads us to ac- 

 count for another respecting ostriches, which are 

 observed by travellers to be absent from their eggs 

 in the day-time, and to sit upon them at night. 

 That they do this, is shown by the fact of the 

 ostrich feathers being of less value during the 

 period of incubation, than they are before or after ; 

 at that time they are tinged with red, which the 

 Hottentots say is occasioned by their sitting on 

 the red earth to hatch their eggs. I have this in- 

 formation from Mr. Burchall, w r ho, however, says 

 that he never saw an ostrich on the nest in the 

 day-time." It is well known to poultry keepers 

 that the common hen is absent for about half an 

 hour each day from her eggs, without their receiv- 

 ing any injury. Sometimes, however, the nest is 

 left for a still longer period. 



