256 The Bird 



small eyes of this bird become dazzled by strong light, 

 its food being detected by the senses of touch and smell. 

 The eyes of the woodcock show an interesting adapta- 

 tion to its habits. The bird feeds at night in marshes, 

 probing the mud for worms and, being in frequent danger 

 of attack from owls or other foes, it has need of constant 

 vigilance. So we find that its eyes, which are large and 

 lustrous, are placed far back on its head and also up near 

 the top of the skull. Useless in guiding the bird in its 

 search for food, they have become altered in size and posi- 

 tion and so best fulfil their function of aiding their owner 

 to all but look through the back of its head. 



Even the iris of a bird's eye may share in the won- 

 derful colour scheme of its feathers, although the most 

 common hue is a hazel-brown. And in birds of two 

 related species or races, there is sometimes a marked dif- 

 ference in the colour of the iris; such, for example, as be- 

 tween the Red-eyed and White-eyed Vireos, or the simi- 

 larly named Towhees. Puffins have blue irides, pigeons 

 pink ones, while young Bald Eagles have brown eyes 

 which, in the adult, turn yellow. The eyes of Barred 

 Owls seem to be a deep, lustrous black, but they are really 

 dark brown; while the great yellow eyes of Snowy and 

 Horned Owls are the most brilliant bits of colour about 

 these birds. In cormorants the irides are a glittering 

 emerald-green. 



It might be thought that "making eyes" was con- 

 fined to the more frivolous of our own race, but certain 

 it is that, whether or not it plays a part in charming the 

 females, the irides of the males of a number of species 



