BRITAIN^S BIRDS AND THEIR NESTS. 229 



on a diet of berries, and the like. Seeds are eaten by very 

 many of the birds, and they form almost the sole food of 

 one of the largest families. The third division includes 

 those birds which subsist chiefly on worms, grubs, and the 

 like. Other types are less frequent ; only a very few 

 species, for instance, are predatory on other birds. 



Great similarity is displayed in the nesting habits of the 

 members of the Order. Most of them build good cup- 

 shaped nests of dry grass, twigs, moss, or other materials, 

 often lined with hair or feathers. Domed nests are built 

 by a comparatively small number of species, and a few use 

 mud or other less common nesting materials. A small 

 proportion make very slight nests. These are principally 

 birds which nest either on the ground, among long grass 

 or broken rocks, or in holes in banks or trees. The usual 

 site for Passerine birds, however, is in herbage, bushes, 

 or trees, at heights above the ground varying from a few 

 inches to many yards. A few are clifF-nesters, but many 

 of these now find suitable sites on human dwellings. 



The number of eggs laid is rarely fixed, as in Waders for 

 instance, but is usually variable within small limits. These 

 limits vaiy in the Order from three to five to about ten to 

 foiuieen. A nearly oval shape is characteristic. In a few 

 species, with domed nests or sites in holes, the eggs are 

 pure white. In most of the ground-nesters they are brownish 

 and markedly protective in hue. But in the majority the 

 eggs are almost white in ground-colour, but with a pink 

 or gi'een tinge, and the markings are irregular spots, 

 generally not very dark, and sometimes collected in a zone 

 towards the broader end of the egg. In a number of 

 species a green or blue ground-colour is found, and this 

 has doubtless some protective value among green foliage, 

 probably against egg-stealing birds or other foes likely to 

 see the nest from above. 



