78 OBSERVATIONS ON THE CUCKOO. 
certainly would present a great difficulty; for the 
feathered. tribes, though capable in some instances of 
connecting vocal sounds with the ideas intended to 
be signified by them, do not possess an artificial 
language: but I am inclined to think that the Hedge- 
Warblers did not intentionally exercise any influence 
whatever over their coadjutor. 
Nestling Cuckoos, it is well known, are extremely 
clamorous when powerfully stimulated by hunger; 
indeed their cry for food is so incessantly repeated on 
such occasions, that it frequently leads to their dis- 
covery. Now this, I believe, is the exciting cause, 
which, by calling into operation the parental affections 
of birds so circumstanced as to be influenced by it, 
impels them to succour the young of strangers, even 
when they have not been placed under their imme- 
diate care ; and the most probable reason which sug- 
gests itself why so many individuals of a kind are 
sometimes associated together in the performance of 
the same task, is that they are attracted by each 
other’s calls. 
The following anecdotes support these opinions. 
A nestling Greenfinch was placed in the same cage 
with an adult Lesser Redpole, which brought it up 
with the utmost care. 
Several young Sparrows, whose nest had been de- 
stroyed, were put into a small basket by a lady who 
pitied their helpless condition, and the basket was 
then conveyed to the grass plot in front of her house. 
