A third of King Charles' royal swans have been wiped out after the animals were struck down by deadly bird flu.
The monarch is said to be "deeply upset" that the beloved flock at Windsor Castle have been killed.
Swan charities have spent six days fishing the floating bodies of more than 60 of the birds out of the River Thames as the pandemic runs riot through them.
In January, the late Queen was told the news that seven of her flock had died and a further 26 had to be euthanised in what was thought to have ended the outbreak.
But it has returned with a vengeance and animal lovers have been warned to stay away from the banks of the river and not to feed them to avoid spreading it.
The royal flock of protected birds numbered 200 on the three-mile stretch of river that winds round Windsor Castle from Romney Lock to Boveney Lock near Dorney, Berks.
But at least 25% of the iconic birds have been lost since Thursday with charity Swan Support pulling 22 dead birds out of the water beneath the Castle on Sunday alone.
Swan Support chief Wendy Hermon, 54, said: ”I have been looking after the royal swans for 30 years beneath the Castle and I have never seen anything like this before.
“In 2018 Avian Flu killed more with about 70 swans lost but that was over about a month but this time they are dying so fast they are literally dying right in front of your eyes.
“On Sunday I was recovering the bodies of three swans that had died by Romney Lock and saw a swan that looked unwell in the water but it did not look as if in real distress.
“But within ten minutes it just rolled over and died right in front of me.
“It is the speed that these swans are dying at that is frightening as they are literally dropping dead in the water all over the place and every day we are pulling them out.
“There is nothing you can do as if you take them in for shelter and to treat them the influenza will kill all of the other birds so you just have to let nature run its cruel course.
“I have 15 volunteers and we are out on the riverbanks and out in kayaks in protective gear and getting as many dead swans out of the water as quickly as we can daily.
“They all go off for immediate incineration in big bins thanks to amazing help from the Royal Windsor & Maidenhead Borough Council who are doing so much to help us” she said.
Signs are going up today all along the banks of the River Thames below Windsor’s historic castle warning visitors not to feed the swans and to stay away from the banks.
A Windsor Castle source said: ”King Charles takes an enormous interest in the wildlife on all the royal estates and beyond and particularly so at Windsor as he is now the Head Ranger.
“He will be deeply upset about this major outbreak and the King’s Swan Marker David Barber who did the job for 30 years for the Queen will be keeping the Palace informed.
“Prince Charles inherited the Queen’s swans when his late mother passed” she said.
The Oxford University professor has been in the role since 1993 and together with the King’s Swan Marker David Barber both lead the annual Swan Upping ceremony every July.
Swan Support chief Wendy added:” This is a heart-breaking task for our rescuers as no matter how long you have been rescuing them this deeply affects you.
“We have agreed with the council to feed the flocks of swans rather than local or tourists to reduce the footfall on the river banks to try and help contain the bird flu outbreak.
“We ask that you please keep to the footpaths away from bird droppings and they you keep dogs on the leads and if you see sick or dead swans call us please on 07968 868172.
The Crown owns all unmarked mute swans found on open water in Britain and the Swan Upping Ceremony is the annual “stock take” of the swans along the River Thames.
Swan Upping dates back to the 12th Century when the ownership of unmarked swans was claimed by the Crown as they were then a delicacy and in demand for royal feasts.
The King only exercises his rights on an 80-mile river stretch from Sunbury on Thames to Abingdon and his official title inherited from his mother is the Seigneur of the Swans.
Both the Queen and the King consider the swans on the three-mile stretch below the Castle as the “royal flock”and the King is the only person in the UK allowed to legally eat them.
The Windsor Castle source added: “Before there is a storm of outrage it has been several centuries since a swan was served up at a royal banquet and that is how it will remain!”.
Signs of swans with bird flu are seeing them swim in circles or drooping their heads.
The charity Swan Support is asking for donations to help their rescue work and feeding of the swans through their Just Giving page.
