CHAPTER XII 
THE COLOURS OF BIRDS 
General Characters of the Coloration of Birds—Sexual Colora¬ 
tion-Distribution of Colour and Colour Variation—Food 
and Colour—Pigments of Birds, their Characters and 
Distribution—Pigments of Birds’ Eggs — Markings of 
Feathers. 
The colours of birds often rival or surpass those of 
insects in brilliancy and variety, and have attracted 
quite as much attention. Indeed, the greater size of 
birds and their greater specialisation give to their 
colouring a variety and a charm which many fail to 
find in insects ; this widespread admiration has un¬ 
fortunately been in many cases singularly fatal to 
the birds. 
Birds resemble insects in displaying both types 
of colour—the optical and the pigmental—to great 
perfection ; but in marked contrast to the conditions 
which prevail in the Lepidoptera, we find that the 
bright pigments are usually lipochromes, never so 
far as is known waste products of the uric acid 
group. Further, although there are several instances 
described of birds whose colours can be heightened 
or altered by the employment of special kinds of 
