"I've packed my own lunch; the trolley, as I remember it, is heavy onlicorice wands, and a poor old man's digestive system isn't quite up to such things... Pheasant, Belby?"
-- Horace Slughorn on the Hogwarts Express (HBP7)
An ordinary game bird, usually roasted.
Professor Slughorn shared a cold pheasant during the Slug Club meeting in Harry's sixth year. Marcus Belby choked on his portion and Slughorn cleared his throat with the spell Anapneo (HBP7).
Horace Slughorn "collects" students, especially those connected to the rich and famous. So it figures he would choose to serve a fancy dish like pheasant, historically connected to hunting parties of the aristocracy and royalty.