CHAPTER XIII 
THE COLOURS OF BIRDS ( Continued ) 
The Structure of Feathers—Relation between Structure and 
Colour—The Colours of Sun-birds, Humming-birds, and 
Birds of Paradise, their Distribution and Characters— 
Markings of Kingfishers — General Characters of the 
Colours of Birds—Meaning of Colour in Birds. 
HAVING in the previous chapter considered some 
general aspects of the colours of birds, we shall now 
proceed to study the coloration of special families in 
detail. In order to make the descriptions readily 
comprehensible, it will be first necessary to briefly 
revise the structure of feathers. 
Feathers are outgrowths of the epidermis, formed, 
like all such outgrowths, of the substance keratin. 
They differ according to their function, and the part 
of the body in which they occur. Thus there are 
the quill-feathers which occur in wings and tail, the 
general contour-feathers which cover the surface of 
the body, and the downs or soft under feathers, 
which are often abundant on the breast. All these 
either contain pigment or are filled with bubbles of 
air and so display a white colour. Before proceed¬ 
ing to describe the distribution of pigment in these 
