What word describes a large, showy feather, often worn as an ornament on a hat or helmet?

Which large breakfast cereal producer has the stock ticker GIS? A large crater on Saturn's moon Mimas is named for which British astronomer who discovered the moon in 1789? What is a large group of bees on the move called? What is a large-eyed needle used to mend holes in socks called? What is a large fire built for a funeral cremation called? Complete the nickname of a large long-range German cannon of World War I: "Big ___". A large one has about 80 calories, so what did Cool Hand Luke eat 50 of, for 4,000 calories? Which word names both a large ruminant and idle chatter?