A bird dog is, literally, a dog bred and trained to work alongside hunters, finding, pointing at, flushing or retrieving game birds. From that working role the phrase has taken on several figurative senses in American English. The most familiar is a verb: to bird dog someone is to pursue them with dogged persistence, and in particular to move in on and take someone else’s date or girlfriend. It can also be used more neutrally for close, relentless tracking of anything at all, whether that is sales leads, opportunities or a rival’s movements, in the same spirit as a dog that will not be shaken off a scent.
What’s the origin of the phrase ‘bird dog’?
The figurative uses grow directly out of the working dog’s job. A bird dog does not give up on a bird once it has located it, and that single-mindedness transferred easily to describing people. Green’s Dictionary of Slang traces the earliest recorded use of the romantic-rival sense to a 1941 glossary of US Army slang among Flying Cadets, which defined the behaviour plainly: “Bird dogging. Lower classman dancing with upper classman’s girl.” The sense stayed in use for years afterwards: a 1957 citation from P. Moore’s novel Chocolates for Breakfast has a character warning off a rival with the line, “Stop bird-dogging my date.”
A separate noun sense developed in criminal circles, where a bird dog meant a contact man or scout working for stock and bond thieves, someone who located and brought in promising marks much as the dog fetches game for its handler. This usage is recorded in Britain from 1931, and it had crossed into American crime writing by 1936 in the fiction of Raymond Chandler, where it describes “a contact man for stock and bond thieves.” Both the romantic and the criminal senses rest on the same image, a dog bred to find something for someone else and then not let go of it, which is why the phrase has survived in such different company, from barrack-room slang to the language of swindlers.