Common Birds of Western Himalayas 



profits by its similarity to a bird of prey. The 

 little birds which it imposes upon are supposed 

 to fly away in terror when they see it, thus allow- 

 ing it to work unmolested its wicked will in 

 their nests. My experience is that little birds 

 have a habit of attacking birds of prey that 

 venture near their nest. The presence of eggs 

 or young ones makes the most timid creatures 

 as bold as the proverbial lion. I therefore do 

 not believe that these cuckoos which resemble 

 birds of prey derive any benefit therefrom. 



The hen European cuckoo difFersvery slightly 

 from the cock. In some species, as, for example, 

 the famous " brain-fever bird " {Hierococcyx 

 varius), there is no external difference between 

 the sexes, while in others, such as the Indian 

 koel (Eudynamis honorata), and the violet 

 cuckoo (Chrysococcyx xanthorhynchus), the 

 sexes are very dissimilar. I commend these 

 facts to the notice of those who profess to 

 explain sexual dimorphism (the different appear- 

 ance of the sexes) by means of natural or sexual 

 selection. The comfortable theory that the 

 hens are less showily coloured than the cocks, 

 because they stand in greater need of protective 

 colouring while sitting on the nest, cannot 

 be applied to the parasitic cuckoos, for these 



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