WHAT IS A BIRD 1 25 



Of these colours that which is known as 

 turacin is the most remarkable. It is found in 

 the red feathers of the turacou or plantain-eater 

 of Africa. In addition to the colouring matter, 

 these feathers contain from 5 to 8% of copper, 

 which can be extracted, Mr Church tells us, by 

 soaking in a little weak ammonia and acetic 

 acid, and filtered off as a metallic red or blue 

 powder. These birds lose the red colour when 

 washed by the rain, but regain it when dry, 

 moreover, this colour is said to tint the water in 

 which they bathe, jusb as is said to be the case 

 with the common heron. 



The second kind of colouring is that produced 

 by the combination of pigment or colouring 

 matter, and certain structural peculiarities in 

 the surface of the feather itself. Yiolet, blue 

 and green, are colours produced in this way. 

 Thus the deep blue feather of a parrot held 

 against the light no longer appears blue, but 

 grey or yellowish. The green feathers of the 

 Amazon parrot, when wetted, appear brown. 

 Blue colouring matter has never yet been found 

 in birds. The blue colour of certain feathers 

 is due solely to structural characters. The only 

 colouring matter discoverable is either brown, 

 black or orange, according to the j^articular tone 

 of the blue. 



To the third form of colouring belong the 

 exquisitely beautiful metallic tones, such as 

 occur in the common English starling, the 

 humming-birds, many pheasants, the " tail " 

 of the peacock, birds of paradise, and so on. 

 These are all due to the structure of Jhe sur- 



