140 RELATION OF SONG TO THE TERRITORY 



often find it difficult, and in not a few cases 

 impossible, to recognise a bird merely by its call. 

 The plaintive notes of the Willow- Warbler and 

 of the Chiffchaff are to our ears very closely 

 akin, so, too, are those of the Marsh- Warbler 

 and of the Reed- Warbler, and there is a great 

 resemblance between the hissing sound produced 

 by the two Whitethroats. In Co, Donegal I 

 have been deceived by the spring-call of the 

 Chaffinch which, owing possibly to the humidity 

 of the atmosphere, is, there, almost indis- 

 tinguishable from the corresponding note of the 

 Greenfinch. The Yellow Bunting and the Cirl 

 Bunting frequently make use of a similar note, 

 so do the Curlew and the Whimbrel. In fact, 

 numberless instances could be quoted in which 

 notes appear to us identical, and, as a rule, the 

 more closely related the species, the more difficult 

 it becomes to distinguish the sounds-^alike in 

 plumage, alike in behaviour, alike in emotional 

 manifestation, it would be surprising if they were 

 not alike in voice. But the moment we pass 

 from the call-notes to a consideration of the 

 songs we are faced with a very remarkable fact, 

 for not only are these readily distinguished, but 

 in many cases they bear no resemblance in any 

 single characteristic. What could be more unlike 

 than the songs of the Willow- Warbler and of 

 the ChiffijhafF, of the Marsh- Warbler and the 

 Reed- Warbler, or of the Yellow Bunting and 

 the Cirl Buntfng ? 



Now when different individuals collect in 

 flocks at certain seasons, they assist one another 



