THE EVOLUTION OF BIRD-SONG. 135 



I wrote, however, as follows : — " In the course of time persistent 

 sounds might, in consequence of the involuntary or voluntary 



imitativeness of a bird, modify its call-note It is also 



possible that certain call-notes may have been intentionally 

 modified to a resemblance of the sounds made in obtaining food, 

 and for the purpose of suggesting those sounds to other birds." 

 I then instanced the behaviour of the barn-door cock — which 

 bird, when calling his hen, pretends to be picking food — as " war- 

 ranting the suggestion" (this was obviously a mere surmise) ; "but 

 often there is certainly, from whatever cause arising, great 

 similarity between the call- notes of birds and the sounds which 

 are occasioned by their obtaining food or eating it." Among 

 other instances I mentioned, ". . .the Blackbird and Thrush, 

 which at times make a clicking sound that is the foundation of 

 the reiterated alarm-notes of the former bird. This is an imita- 

 tion of" (I should have written "is similar to") "the 'clicking' 

 sound produced when a snail is broken against a stone." Let 

 me here add that unless a person has cracked a snail within an 

 inch or two of his ear he is not able to form an idea of the 

 loudness of the sounds which a bird hears when it performs the 

 same operation. I did not state that the Thrush developed its 

 song from this cry, but alluded to it as the third best British 

 mimic with which I was acquainted (Zool. 1N90, p. 242). 



Mr. Fowler proceeds : — " The Swallow's note resembles the 

 sound made by the breaking of the wing-cases of beetles." 

 I wrote:— "The Swallow's call-note 'clit' reminds one of the 

 breaking of the wing-case of a small beetle." The word "note" 

 by itself might be interpreted "song," in which case the expression 

 would be obviously inaccurate. 



Mr. Fowler continues the sentence : " the harsh tones of the 

 Rails suggest the crushing of the tender shells on which they 

 partly subsist." This is the only phrase, so far, quoted without 

 error of meaning. He then humorously misquotes me by 

 remarking that the Corncrake " took a fancy to imitate the 

 noise made by a cow in browsing." Should any reader consider 

 this funny, I trust he will defer his conclusion until on some 

 still night he has been near a cow which is browsing rank grass. 

 Then, and then only, will he be able to judge whether my com- 

 parison was a fair one : — " The ' crake' of the Landrail is in time 

 and tone closely like the noise made by the grazing of a cow." 



