A Theory of Birds' Nests 81 



numerous, comprising, in fact, almost all the bright coloured Passeres, 

 except those enumerated in the preceding class, and far exceeding 

 them in number. The following are the most remarkable : — 



I. Chatterers (Cotingidae.) These comprise some of the most 



gorgeous birds in the world, vivid blues, rich purples, and 

 bright reds, being the most characteristic colours. The 

 females are always obscurely tinted, and are often of a 

 greenish hue, not easily visible among the foliage. 



II. Manakins (Piprid^e.) These elegant birds, whose caps or 



crests are of the most brilliant colours, are usually of a 

 sombre green in the female sex. 



Hi. Tanagers (Tanagridse.) These rival the chatterers in the 

 brilliancy of their colours, and are even more varied. The 

 females are generally of plain and sombre hues, and always 

 less conspicuous than the males. 



In the extensive families of the warblers (Sylviadse), thrushes 

 (Turdidae), flycatchers (Muscicapidse), and shrikes (Laniadae), a 

 considerable proportion of the species is beautifully marked with 

 gay and conspicuous tints ; but in every case the females are less 

 gay, and are very often of the very plainest and least conspicuous hues. 

 Now, throughout the whole of these families the nest is open, and 

 I am not aware of a single instance in which any one of these birds 

 builds a domed nest, or places it in a hole of a tree, or under- 

 ground, or in any place where it is effectually concealed. 



In considering the question we are now investigating, it is not 

 necessaiy to take into account the larger and more powerful birds, 

 because these seldom depend much on concealment to secure their 

 safety. In the raptorial birds bright colours are as a rule absent ; 

 and their structure and habits are such as not to require much pro- 

 tection. The larger waders are sometimes very brightly coloured 

 in both sexes ; but they are probably little subject to the attacks 

 of enemies since the scarlet ibis, the most conspicuous of birds, 

 exists in immense quantities in South America. In game birds and 

 water-fowl, however, the females are often very plainly coloured, 

 when the males are adorned with brilliant hues ; and the abnormal 

 family of the Megapodidae offers us the interesting fact of an 

 identity in the colours of the sexes (which in Megacephalon and 

 Talegalla are somewhat conspicuous), in conjunction with the 

 habit of not sitting on the eggs at all. 



Taking the whole body of evidence here brought forward, em-« 

 bracing as it does almost every group of bright-coloured birds, it 



