An automated musical swan that once enchanted the author Mark Twain has become "too fragile" to work due to lack of use over lockdown.
The 18th Century life-size Silver Swan is operated by clockwork mechanisms and appeared to come to life once a day at the Bowes Museum in County Durham.
But after months of the museum's closure the automaton has seized up and needs to undergo "complex" repairs.
It will remain on show at the museum in Barnard Castle.
The metal and glass structure, which dates from 1773 and contains 30lb (13kg) of silver, is operated by three clockwork mechanisms as it twists its head, preens and catches a golden fish.
Twain saw the swan at the 1867 Paris exhibition and later featured it in his novel The Innocents Abroad, in which he described the "living grace about his movement and a living intelligence in his eyes".
It was later bought by the museum's founders in 1872.
In 2017, it made a rare appearance at the Science Museum's Robots exhibition.
Visitors will still be able to see the model perform on video and its eventual repair will be recorded to show how it works.
"Its age and the complexity of its mechanisms mean it's very fragile and, like so many of us, it has been impacted by the dramatic reduction in its use during the pandemic," said the museum's Alison White.
"The very expensive conservation repair will take time so visitors to the museum will have a once-in-a-lifetime opportunity to see our conservation team at work on film and, at moments, in the museum when work is taking place."