Did you know the Queen of England owns all the unclaimed mute swans in all of Britain? Well, she does, and she makes sure to count them every year in the third week of July. It’s called the Swan Upping, and it's just as amazing as you might think.

1. IT STARTED BECAUSE SWANS WERE FOOD.

The ceremony likely began in the 12th century, when the Crown claimed all unclaimed mute swans. At that time, the birds were considered a delicacy reserved for the banquets and feasts of the wealthy; today, the birds aren't on the plate, but the ceremony continues.

2. NOT ALL SWANS ARE OWNED BY THE CROWN.

In the 15th century, the Crown split ownership of the birds with the Worshipful Company of Vintners and the Worshipful Company of Dyers (both livery companies). To differentiate, Vintners Uppers wear white and black, and the Dyers Uppers wear dark blue during the census. The Queen's Swan Uppers wear traditional scarlet uniforms.

3. THE CEREMONY LASTS FIVE DAYS.

Six rowing skiffs—two each for the Crown, the Dyers, and the Vintners—start at Sunbury and head upstream to Abingdon in a 79-mile, 5-day journey. Each boat flies a flag or pennant that indicates which group of Swan Uppers is on board.

4. SWAN UPPERS ONLY CARE ABOUT THE MUTE SWANS.

Mute swans are the birds with white feathers and an orange bill, bordered with black (as juveniles, they have gray feathers). They are less vocal that other swans but are known to hiss at predators entering their territory. Good luck, Swan Uppers!

5. IT TAKES PLACE IN LATE JULY FOR A REASON.

According to the Vintners [PDF], that's when "the parent birds were in moult and the cygnets were too small to fly."

6. THE ORGANIZER OF THE SWAN UPPING IS CALLED THE QUEEN'S SWAN MARKER.

The role dates back to the 12th century ceremonies and was previously known as Master or Keeper. At that time, the person's main job was to find the best swans for eating. In 1993, the role was split into the Swan Warden and the Swan Marker. The Swan Warden is Christopher Perrins, an ornithologist at the University of Oxford, who monitors the health of the swans during the ceremony. The Swan Marker is responsible not just for organizing the event but also keeping tabs on swan welfare across the country, a role David Barber has been performing since 1993.

7. THE SWAN UPPERS HAVE A RALLYING CRY.

When they spot a brood of swans, the Uppers yell "All up!" It indicates they need to get into position and get ready to grab. The birds are then taken to the shore, where they're examined and marked. In the old days, the birds' beaks were nicked—one for a Dyers' bird, two for a Vintners' bird—but today, they snap bands around the birds' legs. The Crown's swans aren't marked at all. Swans that are injured are either treated on the riverbank or taken to facilities to recuperate.

8. THE QUEEN ISN'T THERE.

Only once in her 63-year reign—in 2009—has Queen Elizabeth II participated. But the Uppers find a way to honor her: According to USA Today, "Before the boats push off, the uppers pour themselves a glass of port and raise it toward the castle, in honor of the absent monarch." Still, because she's owner of all the swans, she gets a name befitting her station: Seigneur of the Swans.

9. ONLY ONE SWAN UPPING IN RECENT MEMORY HAS EVER BEEN CANCELED.

In 2012, the ceremony was canceled due to flooding for possibly the first time in 900 years.

10. NOT ALL OF THE THAMES' SWANS ARE PART OF THE UPPING.

The Swan Upping only occurs on select parts of the River Thames and in certain tributaries. Good thing, or the Swan Upping would last more than 5 days.

11. THIS OLD TRADITION SERVES A MODERN PURPOSE.

Since the royal family isn't dining on these birds anymore, the survey is more about analyzing the health of the swan population and the effects of their various predators.

The census has actually led to the discovery of environmental trends. After swan numbers decreased in the 1980s, lead fishing weights, which the swans were eating, were banned, and the population rebounded. This year, it appears that the serious threat against swans is cygnets being shot by air guns.

12. YOU CAN'T EAT THE SWANS NOW.

Unless you're the Queen, one of her guests, or a fellow of St. John's College Cambridge, eating a swan in Britain these days is a crime: Offenders must pay a serious fine or serve time in prison. Not only are mute swans a protected species—you're stealing from the Queen! Though the ban might be for the best: According to the Vintners, swan meat has "not lived up to its medieval reputation—the muscly legs and wings are very tough."

All photos courtesy of Getty Images.