IMITATIONS OF THE ELEMENTS 181 



is any new feature in the economy of birds ; on the 

 contrary, it has probably existed for a vast period of 

 time. If it has so existed and many birds in 

 captivity will imitate, as we have seen, any prominent 

 sounds near them is it not possible that during 

 a long period many wild birds have unconsciously 

 learnt to imitate sounds persistent in their neigh- 

 bourhood, and that these sounds have been, partly 

 by filial mimicry, partly by involuntary imitation, 

 gradually reproduced in their songs? If naturalists 

 in different parts of the world were to make obser- 

 vations in relation to this matter, I feel sure that 

 many facts confirmatory of my views would be 

 established. 



RESEMBLANCES TO SOUNDS PRODUCED BY THE 

 ELEMENTS 



In describing the notes of the American marsh 

 wren (Certhia palustris\ Wilson stated that, "Standing 

 on the reedy borders of the Schuylkill or Delaware 

 in the month of June, you hear a low, crackling sound 

 something similar to that produced by air-bubbles 

 forcing their way through mud or boggy ground 

 when trod upon ; this is the song of the marsh wren." 

 The belted kingfisher (Ceryle alcyon\ which lives by 

 running rivulets, waterfalls, and milldams, when 



