pollygraph
A device that supposedly determines if a parrot is telling the truth.
Polygraph machines are notoriously inaccurate and unreliable (i.e., they're easy to "beat" by simply going without sleep for two days before the test, and they merely sense if you're nervous, they cannot actually tell if you're lying, and so there are plenty of false positives just because the subject is scared or anxious), but a pollygraph would be even more useless, since a bird doesn't even actually know what it's saying... it merely imitates what it's heard, and so it has no idea if the words it's mindlessly squawking are the truth of not.