Actors get the bird when the performance is so bad that audience rebels, by hissing or booing, or, in more recent years, executing the Bronx cheer.
The expression “to get the bird” was the forerunner of getting the raspberry. It dates from about the middle of the nineteenth century, being first recorded in Hotten’s Dictionary of Modern Slang in 1859.
But, in turn, this expression was preceded by its logical forerunner, “to get the goose,” in allusion to the hissing of the goose, a theatrical phrase that goes back at least to the beginning of the nineteenth century.