Manchester council says the discovery of peregrine falcons nesting in the town hall should be celebrated despite delaying the building's restoration.
Having at one time been close to extinction in the UK, the bird of prey’s numbers are now increasing as the protected species have adapted to nest on tall buildings.
It is the first time in several years that the birds - the fastest animals on Earth - have made the town hall’s clock tower their home.
Peregrines are provided with the highest category of legal protection under the WIldlife and Countryside Act 1981.
This means that it is a criminal offence to intentionally or recklessly disturb birds once a nesting attempt is under way.
But their commandeering of the Grade I listed building has caused problems as Manchester council has been forced to postpone its reopening until later in 2024.
The peregrines, together with the uncovering of asbestos, hazardous tar and the impact of the Covid-19 pandemic, has led to £3.9m in extra costs.
Council bosses insist that while they did not expect to find the birds, contingencies within the £330m budget mean the costs can easily be covered.
Councillor Nigel Murphy, deputy leader of the council, described the peregrines as a ‘natural wonder’ and hoped they would continue to thrive in Manchester for years to come.
He said: "While nobody could have reasonably foreseen that the peregrines would choose to nest on the clock tower, as they have used different buildings in recent years, we see them as an iconic part of the city's heritage, just like the town hall itself.
"With a project this big and complicated, it is not unlikely for there to be some surprises along the way.
“While we couldn't have expected these specific circumstances, we did take the sensible step of building contingency funding into the project budget, which enables us to absorb them.”
Work to safeguard the nesting birds began in early spring when the council was informed of their presence by the Manchester Raptor Group.
The council says that once work on the clock tower scaffold is completed, it will be wrapped to block access by the birds until the wider redevelopment is finished.
There are then plans to provide the birds with a suitable gravel bed in the clock tower to provide an attractive place for them to lay their eggs.
