BRITISH WARBLERS 



attention solely owing to the size of the bird and the con- 

 spicuous colouring of the plumage, but in the case of the 

 Blackcap, and also of many other of our most common native 

 species, the conditions are entirely reversed, for they are 

 small, their plumage is inconspicuous and dull, their per- 

 formances are more quickly executed, and consequently very 

 close attention to their habits is necessary, in order, not only 

 to see, but to realise what is actually taking place. Yet their 

 antics are no less remarkable. The difference is only one of 

 degree, not, however, in the performance, but in the plumage. 

 Imagine the Blackcap possessed of the gorgeous plumes of 

 many other species, and his exhibition would be a truly 

 remarkable one. During this time of excitement the feathers 

 on the head, especially the black cap, are raised, but some- 

 times alternately raised and lowered, those on the breast 

 and flanks are fluffed out and the throat is often distended, 

 but more particularly so when singing. The feathers on the 

 back are raised disproportionately, giving one the impression 

 that one or two of the longer ones were being moved inde- 

 pendently of the others, the wings are drooped or extended- 

 fully and flapped, the scapulars raised, the tail-feathers quickly 

 spread out and as quickly contracted, and the tail itself either 

 raised or lowered at various angles. The tail is often spread 

 out to such an extent that large spaces appear between the 

 different feathers, and is sometimes carried at right angles to 

 the bod} 7- . When the flapping flight is in progress the wings 

 are fully extended, and as far as it is possible to tell, the 

 feathers all over the body are relaxed. 



We now come to the part played by the vocal powers in 

 the courtship. According to the theory of sexual selection, 

 song has been developed in the males owing to the females 

 being more sexually excited by, and consequently pairing 

 with, those whose vocal powers were developed in the highest 

 degree. The male Blackcap is one of the most beautiful — 

 and in the opinion of some, the most beautiful — of our 

 native songsters. His rich and liquid notes will bear com- 



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