EGGS AND EGG-COLLECTING. 11 



Still further, where birds are conspicuous in colour they 

 either build covered nests, or place them in such situations 

 as afford safety, and are thus equivalent. For instance, the 

 Woodpecker, Kingfisher, and Magpie, the two former having 

 a double object in the selection of a situation, firstly their 

 own eminently brilliant colours, and secondly theirpure white 

 eggs. The latter building a covered nest of such materials 

 as thorns, seems to point to a strategic planning against 

 the immorality of the family to which he belongs. 



Periods of Incubation and their Utility. — The 

 Duck family all lay eggs white, or nearly approaching it, 

 and take the precaution to cover them carefully on leaving 

 the nest. 



Some naturalists have been of opinion that this is to 

 prevent an undue escape of the heat generated by the 

 parent ; however, I am unable to find any observations to 

 prove that these birds leave their eggs for feeding purposes 

 longer than any others that hatch their young in three 

 weeks. Neither does it appear that they transmit heat better 

 or worse than birds of entirely different habits, for it takes 

 a Fowl four weeks to hatch a Ducky's egg, and a Duck will 

 on the other hand hatch a Fowl's in the normal time, three 

 weeks. It appears that the period of incubation is regulated 

 with a great amount of precision by the contemplated 

 habits of life, the diflBculties to be overcome, and dangers 

 to be endured, as the following facts show : — 



A Pigeon hatches its young out in sixteen days, and 

 by a special process and careful assiduity feeds them until 

 they are almost full grown. A Fowl, though not capable 

 of feeding her young in the same way, possesses the power 

 of defending her offspring, finding and selecting suitable 

 food, and attending to their education generally in a higher 



