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 

 yelloAvish-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 Avell 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, jDrobably, 

 a similar case of general protective harmony to that of the 

 green caterpillars with beautiful white or i)urple bands and 

 spots, which, though gaudily conspicuous when seen alone, 



