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circumstances. The fact of birds of different species being 
mutually aided, as they are, by their various alarms, when 
_ danger approaches, is evidence of their being influenced by the 
utterances of their unrelated companions. If influenced by 
alarms, why not by songs ? 
There is one fact which speaks volumes in favour of 
_ diversity and meaning of tones in the voices of birds, and this 
is the wonderful amount of vocal exercise, or possibly of vocal 
_ expression, which exists amongst gregarious species. House- 
sparrows, titmice, linnets, and starlings in flocks chatter for 
hours every day, and it is utterly nonsensical to suppose that, 
while every habit of body serves some purpose in the lives of 
individuals, this abundant interchange of sounds between birds 
is a meaningless consequence of an instinctive impulse. 
Though we shall never be able to translate all the 
- inflections in the voices of birds, yet there are certain widely 
distinct recognisable character-sounds about which we may be 
tolerably certain, and upon these principally have my observa- 
tions been founded. For example, the common domestic fowl, 
when extremely terrified, utters a loud, repeated yell, “cah, 
eah, cah.” We may fairly say that this cry is a character- 
sound which, when uttered by any fowl excited by extreme 
fear of death in the hands of man, has always practically the 
same intonation. Yet even this cry is modulated in an infinite 
variety of degrees of vehemence. The young chicken utters it 
_ when looking closely at a bee, or a wasp; the adult hen, when 
_pecked by another, expresses alarm or distress by the ejacula- 
tion of this cry, but with a degree of force directly propor- 
tionate to the extent of suffering endured; and the adult 
barn-door cock employs the same yell to signal the approach of 
a flying bird of which he is afraid. Thus there is every grade 
_of this cry, from a chirp to a loud yell; yet in every individual 
the yell sounds much the same, and conveys to our minds the 
idea that the bird which utters it is greatly afraid. 
In my papers in the Zoologist I stated that the voice might 
K 
