io BIRDS OF LA PLATA 



species, he certainly does mock the notes of indivi- 

 duals of his own species ; for it must be borne in 

 mind that no two individuals sing quite alike, and 

 that the same bird constantly introduces new notes 

 into his song, and never repeats his notes in the same 

 order* I have often observed that when a bird while 

 singing emits a few of these new notes, he seems 

 surprised and delighted with them ; for, after a 

 silent pause, he repeats them again and again a vast 

 number of times, as if to impress them on his memory. 

 When he once more resumes his varied singing, for 

 hours and sometimes for days the expression he has 

 discovered is still a favourite one, and recurs with 

 the greatest frequency. But this is not all. If the 

 new note or phrase happens to be a very striking 

 one, it immediately takes the fancy of all the other 

 birds within hearing, and often in a small thicket 

 there will be a dozen or twenty birds near together, 

 each sitting perched on the summit of his own bush. 

 After the new wonderful note has been sounded 

 they all become silent and attentive, reminding one 

 in their manner of a caged Parrot listening to a sound 

 it is trying to learn* Presently they learn it, and are 

 as pleased with its acquisition as if they had dis- 

 covered it themselves, repeating it incessantly* I 

 noticed this curious habit of the bird many times, 

 and on one occasion I found that for three entire 

 days all the birds in a small thicket I used to visit 

 every day did nothing but repeat incessantly two or 

 three singular notes they had borrowed from one of 

 their number* The constant repetition of this one 



