16 HABITS AND INSTINCTS OF ANIMALS. CHAP. J. 



own island, although the nests of each particular 

 species, when built in the open country, are always 

 essentially on the same principle ; yet, when found near 

 towns or villages, where the same materials are not to 

 be procured, their formation is adapted both to the 

 situation in which they are placed, and to the substance 

 of which they are constructed. * The nest of the com- 

 mon wren ( Troglodytes Europceus) illustrates the above 

 fact : if built against a haystack, it will be uniformly 

 made of hay; if attached to a tree covered with white 

 lichen, it will be chiefly covered with the same sub- 

 stance ; and so on, according to the place which it may 

 chance to occupy. The obvious intention, however, in 

 every instance, is to provide against discovery, by 

 assimilating the exterior of the nest as near as possible 

 to the object close to it. 



(19.) In rearing their young, other instincts become 

 developed. The ostrich will exemplify this second 

 branch of our subject ; and this unjustly slandered bird 

 is now relieved from the odium which the ancients 

 attached to her, since it is proved that she not only 

 hatches her eggs, but that she reserves others, to pro- 

 vide the young with nourishment when they first burst 

 into life. In Senegal, where the heat is extreme, the 

 ostrich, it is said, sits at night only, upon those which 

 are to be rendered fertile ; but at the Cape of Good 

 Hope, where the sun has less power, the mother re- 

 mains constant in her attentions to the eggs, both day 

 and night. The instinct of this bird, in providing 

 food for its young, appears to be without parallel, and 

 is thus noticed by Le Vaillant : " During this day's 

 journey, I met with the nest of an ostrich, upon which 

 the female was hatching : there were three eggs de- 

 posited on the bare ground, lying before her ; and she 

 was sitting upon nine others, the young of which were 

 in so advanced a state as to be ready to burst the shell." 

 The separation of the eggs in this manner into two 

 parcels one parcel intended to supply the first food 



* White's Selborne, vol. ii. p. 70. 



