A stool pigeon is an informer, especially a criminal who feeds information to the police. The name comes from the decoy bird of American hunting, a pigeon fastened to a stool or perch to draw other birds within range. The term is American and in print from 1806; the informer sense follows in the 1830s.
What’s the origin of the phrase ‘Stool pigeon’?
Both Etymonline and Green’s Dictionary of Slang say that this expression derives from the hunting practice of fixing a dead or replica pigeon on to a stool to act as a decoy to attract other birds.
What the stool in question was isn’t entirely clear. It certainly wasn’t the three-legged piece of furniture we now know, but one of the many other meanings of the word. In the 16th century a ‘stoale’ was the base of a tree - what we would now call a stump, just the place for a decoy bird to sit. It is also possible that ‘stool’ is derived from ‘estale’, which is an early French word applied to a pigeon used to entice a hawk into a net. It isn’t far from ‘estale pigeon’ to ‘stool pigeon’.
Etymonline puts the same idea in plainer terms, taking the stool to be ‘the movable pole or perch to which a pigeon was fastened to lure wild birds’. It sets a related word beside that ‘estale’ guess: ‘stall’, meaning a decoy bird from about 1500 and in particular ‘a pigeon used to entice a hawk into the net’. Etymonline allows that the stool may have been the original device, but thinks the two words may have converged.
All of that seems quite straightforward, except for the fact that the term ‘stool pigeon’, or ‘stoolie’, doesn’t appear in print until the 19th century and in a completely different context. It is first used in American publications and referred to criminals who lured others into crime rather than to decoy birds. The earliest example I can find of the expression is from May 1816 when it was used in the Gettysburg paper The Adams Centinel, in a story about fraudulent paper-makers, that is, counterfeiters. Unfortunately, the print quality of the paper makes it difficult to read the full context, but it does describe someone involved in encouraging the passing of counterfeit banknotes as a ‘procuror or stool pigeon’.
Green’s Dictionary of Slang goes back a decade further, to the New York Evening Post of 15 September 1806, which mocks ‘the ludicrous farce of making a stool pigeon of the “beastly” representative of a petty Barbary power, for the purpose of decoying Congress’. Green’s also records the same ‘procuror, or stool pigeon’ wording in another Pennsylvania paper of the same month, the Carlisle Weekly Herald of 2 May 1816, where enough of the text is legible to show who the man was working for:
He acts as procuror, or stool pigeon, to a Faro bank […] and divides the spoil with four other sharpers of the black leg tribe.
There are examples of decoy ducks being described as ‘stools’ from 1825 onwards, but the term ‘stool pigeon’ isn’t used with that meaning until 1871, when M. Schele De Vere listed it in Americanisms; the English of the New World:
Stool-Pigeon… it means the pigeon, with its eyes stitched up, fastened on a stool, which can be moved up and down by the hidden fowler.
Etymonline dates the decoy bird sense earlier than that listing, to 1812, and gives 1821 for a stool pigeon in the sense of one who betrays the unwary. On its reckoning the bird and the human decoy were both in print long before Schele De Vere wrote them down.
It could be that decoy ducks have been called ‘stool (or estale) pigeons’ since the 1500s but no one wrote the terms down, although that seems rather unlikely. What we do know is that the current meaning of informer came into being in the USA around the middle of the 19th century. The Sheboygan Mercury printed a piece in August 1851 about the prevailing political situation in Italy:
“Everyone fears that his confederate may prove a traitor… and avoided as a Police stool-pigeon and spy.”
Green’s Dictionary of Slang has the informer in print nearly twenty years before that, in the New-York Daily Advertiser of 5 December 1833, reporting a stolen coat: ‘J. Edwards, a sort of stool pigeon as he is called by the department… Turning traitor to his accomplice, [Edwards] informed against him sufficiently to have him arrested’. The authorities do not agree on when the sense settled: Etymonline puts the police informer at 1859, later than either newspaper example.
The most likely explanation of the phrase’s origin is that it was coined to describe those police informers who hung around bars (on stools no doubt) in order to pick up underworld gossip but that the name was influenced by the earlier, but as then unnamed, hunting decoys.
That is the sense that survives. Cambridge Dictionary defines a stool pigeon as a person, often a criminal, who gives information in secret to the police so that they can catch other criminals. The decoy is still there in the idea: the informer is put among the people the police want to catch. British English has grass up for the same act, and it is not the same job as a whistle-blower, who raises the alarm from inside an organisation rather than working for the police.
See other phrases that were coined in the USA.