E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Singing in Tribulation.
Confessing when put to the torture. Such a person is termed in gaol slang a canary bird.
This man, sir, is condemned to the galleys for being a canary-bird. A canary-bird! exclaimed the knight. Yes, sir, added the arch-thief; I mean that he is very famous for his singing. What! said Don Quixote: are people to be sent to the galleys for singing? Marry, that they are, answered the slave, for there is nothing more dangerous than singing in tribulation.Cervantes: Don Quixote, iii. 8.