THE VOICE. 
39 
distinguish them from sounds expressive of aversion, 
hate, sadness, suffering, restlessness and discomfort. 
Some of these sounds have, under the names of decoy 
and warning tones, received well known designations, by 
reason of their being the most common. But besides 
these, many other words in the language of birds might 
be pointed out; for tones expressive of the same meaning 
are always very much alike in different species. An 
instinctive perception of the meaning of these sounds 
generally gives an expert the correct interpretation, the 
more so that the sound of the words (an expression I 
will use) are based upon the same conditions as the 
language of man. The sharp short cry of a bird 
invariably betokens fright; while a long - continued 
repetition of a cry denotes pleasure; but a slight abrupt 
sound is always a note of warning; whereas the same 
tone, if sustained for any length of time or reiterated, 
undoubtedly expresses satisfiaction. The notes denoting 
tenderness and love are quite as melting as, and often 
much more so than, with man, and are expressive of 
greater self-devotion. The cry of pain is a low sound 
within the bird’s throat. Contempt and hatred find their 
expression amongst birds in different sounds, even with 
those birds in whose well-toned song not a single discord is 
to be detected. The Nightingale shrieks abominably when 
in a passion or wishing to express her hate. We need 
scarcely wonder, then, that the observer can very soon 
learn to understand birds hitherto unknown to him, 
although he can hardly explain how he does so. 
To what extent birds can understand a language, 
common to all, one can see plainly in places favourable 
to gregarious assemblages of different species. Here the 
cleverest and the shyest of those present very soon take 
