242 BIRD BEHAVIOUR 



richer-coloured breast to a poorer-hued but per- 

 fect bird, and a hen Avadavat (Estrelda amandava) 

 prefer in two cases a bright to a duller-coloured 

 male. 



If birds have the aesthetic sense with which 

 Darwin credited them, they may, like us, think 

 more of small differences than large ones ; golden 

 hair is generally admired by man, but no good 

 judge would put it, as a point of beauty, above 

 well-chiselled features, though it catches the eye 

 more at first. As against the possibility of birds 

 generally being colour-blind, we may perhaps set 

 the preference of the Australian Satin Bower-bird 

 (Ptilonorhyncbus holosericeus) for blue when choosing 

 decorations for its bower, and the liking of some 

 Weaver-birds for green and yellow wool when given 

 this substance to amuse themselves with in a cage. 

 It will be noted that yellow is a common colour 

 among Weavers, and that the eyes of the above- 

 mentioned Bower-bird are blue, a very rare colour 

 in live birds' eyes, though taxidermists are fond of it 

 in glass ones ! 



Before leaving the subject of the sense of sight 

 in birds, attention must be drawn to its extra- 

 ordinary acuteness in Humming-birds, which, as I 

 have been able to observe in the case of captive 

 birds, appear to be able to see glass ; at any rate 

 they do not fly against it as other birds constantly do. 



The sense of smell in birds seems to be little 

 developed as a rule, not more than in ourselves, at 

 all events judging by their behaviour. 



