TWO rather unexpected guests have taken up residence at York Minster and they could be about to be joined by more.
Enthusiasts have been watching two peregrine falcons nesting high up on the gothic cathedral during recent months and believe they may now be about to extend their family.
The peregrines, which are a protected species, have been seen mating and nest scraping - behaviour which experts suggest means they are about to lay eggs.
Mark Thomas, senior investigations officer at the RSPB, said: “While peregrines don’t physically build a nest, they do construct a scrape – a shallow depression deep enough to prevent eggs from rolling away.
“They normally choose raised locations - for example cliff edges - but tall buildings are increasingly being used, so York Minster will seem like a perfect home to them.
“Their breeding season is in late March or April and this, along with the behaviour observed over recent weeks, suggests the female is about to lay eggs.
“In the British Isles peregrines do not migrate and the majority stay within 100km of their birthplace, so any offspring may well stay within the Yorkshire area.”
The female peregrine normally lays three to four eggs with both birds sharing incubation, which normally takes around 29-32 days per egg. The birds are renowned for their speed and can reach up to 180km per hour when catching prey.
A flurry of emails from the public alerted Minster staff to the birds’ presence and when the reports were confirmed, it was decided that maintenance work to the North Tower would have to be postponed to avoid disturbing them.
Rebecca Thompson, superintendent of works at York Minster, said: “We’re excited the peregrines have chosen this iconic building to nest and look forward to following their story.
“We’re taking advice from experts to ensure we protect the birds from any disturbance as we continue our ongoing restoration and conservation work on the building’s 800-year-old fabric, and hope to have news of new arrivals soon.”
The birds are known to hunt mice and voles for sustenance, often flying back to their nesting spot to consume their prey.
After Peregrines had taken up residence on the peaks of the building in the past, Minster staff have discovered the bones of small rodents on masonry close to where the birds had been perched.
Incredible eyesight would be needed to spot the birds on the building as they are nesting right at the top of the Minster. They are best viewed through long lens cameras from Dean’s Park behind the building.
The birds are not expected to cause damage to the stonework. Droppings are acidic and can degrade building materials but once the peregrines have moved on, their nesting spot will be blasted clean with water fired from an industrial strength cleaner.
North Yorkshire wildlife artist Robert Fuller ventured into York to take a look at the peregrines in November - when this particular pair of birds were first spotted occupying the North Tower.
He said: “It’s very exciting that the peregrines are now breeding on the Minster and a great asset for York. It’s such an iconic site, you can see the Minster from miles around, and will only add value to this beautiful place.
“When I’ve been there watching peregrines, people have been so enthusiastic and have asked if they can look down the telescope to enjoy them.”
The sighting at the Minster is not the only one of breeding peregrines in Yorkshire this week. Another pair have been seen mating at Wakefield Cathedral.
Keen birder and photographer Will Forrest, of Ossett Brewery, saw the birds of prey breeding as he walked to work last Friday and again saw them mating on Monday.
The peregrine is a large and powerful falcon with long, broad, pointed wings and a relatively short tail.
Its coat is blue-grey above, with a blackish top of the head and an obvious black ‘moustache’ that contrasts with its white face.
The strongholds of the breeding birds in the UK are the uplands of the north and west and rocky seacoasts.
Peregrines have been illegally killed in the past and have been a target for egg collectors, and so better legal protection has been brought in.
The better control of pesticides is also thought to have helped the population to recover from a low in the 1960s.
There are thought to be approximately 1,500 UK breeding pairs.