VIII 
ORIGIN AND USES OF COLOUR IN ANIMALS 
215 
it breeds, giving it complete protection from enemies. Thus 
the pale or bluish ground colour of the eggs of its allies, the 
auks and puffins, has become intensified and blotched and 
spotted in the most marvellous variety of patterns, owing to 
there being no selective agency to prevent individual variation 
having full sway. 
The common black coot (Fulica atra) has eggs which are 
coloured in a specially protective manner. Dr. William 
Marshall writes, that it only breeds in certain localities where 
a large water reed (Phragmites arundinacea) abounds. The 
eggs of the coot are stained and spotted with black on a 
yellowish-gray ground, and the dead leaves of the reed are of 
the same colour, and are stained black by small parasitic fungi 
of the Uredo family ; and these leaves form the bed on which 
the eggs are laid. The eggs and the leaves agree so closely 
in colour and markings that it is a difficult thing to dis¬ 
tinguish the eggs at any distance. It is to be noted that 
the coot never covers up its eggs, as its ally the moor-hen 
usually does. 
The beautiful blue or greenish eggs of the hedge-sparrow, 
the song-thrush, the blackbird, and the lesser redpole seem at 
first sight especially calculated to attract attention, but it is 
very doubtful whether they are really so conspicuous when 
seen at a little distance among their usual surroundings. For 
the nests of these birds are either in evergreens, as holly or 
ivy, or surrounded by the delicate green tints of our early 
spring vegetation, and may thus harmonise very well with the 
colours around them. The great majority of the eggs of our 
smaller birds are so spotted or streaked with brown or black 
on variously tinted grounds that, when lying in the shadow of 
the nest and surrounded by the many colours and tints of 
bark and moss, of purple buds and tender green or yellow 
foliage, with all the complex glittering lights and mottled 
shades produced among these by the spring sunshine and by 
sparkling raindrops, they must have a quite different aspect 
from that which they possess when we observe them torn 
from their natural surroundings. We have here, probably, 
a similar case of general protective harmony to that of the 
green caterpillars with beautiful white or purple bands and 
spots, which, though gaudily conspicuous when seen alone, 
