RECOGNITION OF COLOURS 233 



Just as Maegiilivray suggested the Sparrow-Hawk 

 was short-sighted, so Professor Newton, in his 

 " Dictionary of Birds," remarks, with reference to 

 the easy-going way in which the Hedge-Sparrow 

 accepts an aKen egg, that for all we know to the 

 contrary it may be colour-blind ; and within the 

 last few years, a fancier writing to the Feathered 

 World about Homing Pigeons has said that though 

 they can distinguish black from white, this is not 

 the ease with colours. ^ 



The possibility of some birds not seeing as we 

 do must therefore be borne in mind, but as regards 

 the class as a whole the general evidence certainly 

 tends to bear out the commonly accepted idea that 

 their vision for colour is the same as our own. 

 This is shown in several ways ; for instance, they 

 recognize colour in other birds, and display either 

 friendship or hostility in consequence, according 

 to whether they are at the time in need of com- 

 panionship or in a position to feel jealousy. Birds- 

 which are normally spiteful, for instance, are likely 

 to attack a species which bear colours reminiscent 

 of their own ; thus Jenner Weir told Darwin of 

 a case in which a Robin in an aviary killed a red- 

 breasted Crossbill and injured a Goldfinch ; and 

 an American Indigo-^bird (Cyanosfiza cyanea) at- 

 tacked a Nonpareil (C. ciris), which has a blue 

 head, and nearly scalped it. I have myself seen a 

 mated Blue Australian Wren (Malurus cyaneus) in 

 one of the Zoo aviaries furiously pursue a cock 

 Yellow-winged Blue Sugar-bird {Cmfeba cyanea), 



