What is the origin of the idiom have a bird?

Answer 1

I recall hearing this expression for the first time when I was in high school in the 1970's, which is when I believe it originated. The original expression was "have a bird turd" which meant you would get so worked up you would (figuratively) excrete a small pellet. We said this for a few years, and then we shortened it to "have a bird" which got around the admonitions from teachers and other authority figures regarding the use of "bathroom" language.