128 CLASS AVES. 



is not more calculated to gratify private vanity than to be 

 generally useful. Well does Lord Bacon remark on this subject: 

 " Industria scriptorum enituit ; ita tamen, ut potius luxuriata 

 sit in superfluis (iconibus animalium aut plantarum et similibus 

 intumescens) quam solidis et diligentibus observationibus 

 ditata, quae ubique in historia naturali subnecti debebant." 



As vivacity of colour in the plumage is a characteristic of 

 the male birds, so those which are most particularly distin- 

 guished by brilliant colours are of the most ardent character, 

 and vice versa. Birds of lively and striking colours abound 

 most in the tropical climates. Those of cold countries have 

 generally a pale and dead kind of plumage, for cold diminishes 

 as much as heat increases this ardour of constitution. Hence 

 it also happens that most males are produced in the warm 

 climates, and most females among the northern species. We 

 find that the aquatic races, the palmipedes, the scolopaces, the 

 grallae, vi^hose plumage is generally grayish, dull, tarnished, or 

 livid, and which have more females than males, abound prin- 

 cipally in the climates approximating to the poles. Whereas, 

 the climbers, the insectivora, the parrots, the woodpeckers, the 

 colibris, the birds of paradise, the toucans, &c., whose plumage 

 is of the most brilliant dye and richest variety of tints, have 

 also in their species more males than females, and inhabit the 

 warm climates almost exclusively. Paleness and whitishness 

 of colour denote efferaination and debilitation ; and domesti- 

 cation, which degrades the animal, commences almost invari- 

 ably in the individual by a degeneration of colour, as Ave find 

 to be the case with canary birds, pigeons, &c. 



The birds of cold countries are, in general, polygamous, in 

 consequence of the fewness of males in proportion to females 

 in each species. The birds of warm countries, having many 

 males and few females, are, on the other hand, monogamous. 

 It is singular enough that just the reverse is the case with the 

 human species. It also happens, that among the polygamous 

 families, the males are more vigorous than among the mono- 



