54 



The Bird 



probably ever given a thought to the colours themselves 

 Why is that feather blue? Why — because it is blue! 



There are two principal ways in which colours are 

 produced in feathers: first, when a real colour-pigment 

 is present, and again when the structure of the feather is 

 more or less like miniature prisms in shape, breaking up 



Fig. 36. — Young Brown Pelicans in the downy plumage. 1/G natural size. 



the raj's — rainbow-like — into the iridescence of the spec- 

 trum. In the case of almost all the beauties of Nature, 

 the more closely w^e examine them, the more beautiful 

 the}^ become. But this is not true of the iridescent 

 colours of birds such as hummingbirds, unless we con- 

 sider the structure. The colour itself disappears under 

 the microscope, and only gray or black tints are seen. 

 The black, red, brown, and yellow colours of feathers 



