This phrase originates from Humboldt, Saskatchewan, Canada. Heard in the halls of HCI, this phrase was originally used to mock Jared Klimosko, whose nickname is "Bird." Cody Spence and Richard Harbison are the ones responsible for starting this idiotic trend.
Why was this phrase created? Bird just wouldn't sit down.
Richard: Birdgie! Sit down!
Miss Philips: Would you two shut the hell up?
(Bird sits down.)