A pirate needs a parrot and a parrot needs a pirate. It's just common and accepted sense. A pirate can't possibly hope to pillage the high seas without Parrot Pirate Accessory perched on his shoulder. A pirate without a parrot is like a bird without a feather and needs it like the angels need a heaven. So, don't be the only corsair sailing through the Caribbean or wherever else that doesn't have the Parrot Pirate Accessory watching over him.
The Parrot Pirate Accessory is that final touch that a corsair on Halloween needs to make his costume complete. Without a parrot on his shoulder, a pirate is just a smelly jerk on a boat.