138 CLASS AVES. 



The passeres have eggs, the ground of which is white or 

 whitish, bkie or bkiish, green, visually spotted with deep co- 

 lours, such as red, brown, and black. 



The Tomtit kind, which nestle in the holloAVS of trees, have 

 eggs altogether white, or white picked with red. The same is 

 the case with the sivallows and martens. The larks, pipis, <^c., 

 have the eggs of an earthy hue. The nest is scarcely finished 

 when the bird commences to lay, and if the eggs be removed 

 in proportion as they are deposited, they will lay a greater 

 quantity. But the number, though undetermined, is more 

 considerable among the polygamous species, such as the pal- 

 mipedes and gallinacea, than among the monogamous. 



The birds of prey , such as the eagle, the vulture, and the 

 falcon, lay but two, or four eggs at most, each brood. Most 

 of the divers, &c., only one, but which is very bulky. 



The rapacious birds are less fruitful than the other species, 

 more particularly so than the small granivorous and insectivo- 

 rous races. This, indeed, seems a wise provision of Nature in 

 all cases ; but, in truth, it must be the infallible result of the 

 peculiar constitution and regimen of animals. Those which 

 derive their subsistence from the vegetable kingdom, must na- 

 turally be more numerous, as their food is more plentiful ; and 

 the smaller races more especially so, as each individual con- 

 sumes a smaller quantity. 



Hens often lay infecundated eggs, which the Romans called 

 ova subventanea, and the Greeks ua vTrsviixsHx, because they 

 imagined them to be produced by the influence of the zephyrs. 

 Many other birds are also liable to lay infecundated eggs. 



The attachment which birds exhibit in the process of incu- 

 bation is very singular in animals of such a volatile consti- 

 tution. The mother, seated the live-long day upon her eggs, 

 forgets all the necessities of nature ; she passes hours, days, 

 and weeks, under the influence of an instinct, whose domina- 

 tion is as imperious as its cause is incomprehensible. Her 

 natural character undergoes a temporary change, and flinging 



