Look, Pete knew his Quidditch history. So even as tipsy as he was (three or more sheets, wind, etc.), he knew immediately what the big gold feathery ball was.
He finished his drink and, absent any other relevant task, took off at a brisk jog and flung himself onto the big round bird man. "Mine!" he declared smugly, tightening his hands in the gobs of feathers when the bird man's knees buckled and he went down. Pete bounced a little off the birdman's side when they went down, and then promptly found himself on his back, smothered by feathers and fabric and the smell of something fermented. "Victory," he elaborated, blowing a golden feather out of his nose. "For Gryffindor."