CNN  — 

Merlina, a 14-year-old raven and one of the Tower of London’s permanent residents, has gone missing and is feared dead.

A spokeswoman for Historic Royal Palaces told CNN on Thursday that Merlina had flown off two weeks ago and not returned, which “indicates to us that she may have sadly passed away.”

Ravens have been a mainstay at the Tower of London – England’s most famous execution site – for centuries.

It was built in the 1070s by William the Conqueror as a castle and fortress and later became a place for royalty to store arms and jewels. To this day, the Crown Jewels are kept on site, protected by a garrison of soldiers.

Merlina, a 14-year-old raven at the Tower of London, is feared dead.

But it also has a dark and bloody past, having been a prison for many hundreds of people, including Elizabeth I, Anne Boleyn and Guy Fawkes, and the execution place of Henry VI.

In the 1600s, Charles II decreed that six of the birds must live at the tower at all times, otherwise the kingdom and the tower would fall. The tower will now be left with seven of the intelligent birds – Jubilee, Harris, Gripp, Rocky, Erin, Poppy and George – as they keep one spare for safekeeping.

The spokewoman told CNN that Merlina was a “unique” bird who had a “close bond” with Ravenmaster Christopher Skaife – whose job it is to look after the birds.

Merlina and the Ravenmaster are said to have a "close bond" -- making it unusual for her not to have returned.

The raven would play tricks with him, the spokewoman said, and would always return to her nest at the tower at night after roaming freely.

The spokeswoman said they believed she had most likely died as it was out of character for her not to have returned.

Merlina was also a markedly independent bird, having only paired off with a male last year, the spokeswoman added.

“Since joining us in 2007, Merlina was our undisputed ruler of the roost, Queen of the Tower Ravens.

“She will be greatly missed by her fellow ravens, the Ravenmaster, and all of us in the Tower community,” the spokeswoman added in a statement.