The first grey seal pup of this winter has been born on a remote shingle spit on the east England coastline at an area that was once a cold war military weapons testing site.

Earlier this year, the National Trust announced that Orford Ness had become the home of Suffolk’s first breeding colony of grey seals, after steady increases were recorded in the number of grey seal pups being born there. 

During the 2023-2024 breeding season – which runs between October and March and during which the site is closed to visitors – over 130 pups were born on Orford Ness. The birth of the first seal pup of this winter there now marks the fourth consecutive year of successful breeding at the coastal site.

“We’ve been eagerly awaiting the arrival of this year’s seal pups,” said Matt Wilson, countryside manager for the Suffolk and Essex Coast portfolio at the National Trust. “Since October, our team has been avidly monitoring the shores of the Ness from a safe distance and performing regular counts of the adult seals, with some records showing over 200 adults.”

According to Wilson, the first pup arrived a week earlier than last year – an occurrence that has similarly been observed in rookeries “elsewhere in the UK.”

The waters around Britain and Ireland support around 40% of the world’s grey seal population, a figure that’s estimated to be close to 300,001. In the wild, female grey seals – known as cows – can live for 30 to 35 years, while males live for about 20 to 25 years. Cows have their first pups between the ages of three and five and usually return to the same place each year to give birth.

Typically, grey seal pups weigh around 13kg at birth and are covered in a thick white coat. Unlike their common seal cousins – which are born through the summer months and can swim within just a few hours of being born – this coat keeps them warm but isn’t actually waterproof, which puts them at risk of drowning.

These pups will then feed up to six times a day for around 10 minutes at a time. This is their chance to imbibe on fatty, nutrient-rich milk from their mothers. They will be weaned off this at around three to four weeks old, once they have shed their white coat through a process known as moulting. At this point, their weight would have increased to between 45 and 50kg.

“Understandably, this is a crucial stage of the seals’ development,” said Wilson. “To give them the best chance of survival, we limit access to the colony and monitor them only from a safe distance. While the rangers on Orford Ness have undertaken specialist training for monitoring seal health, welfare, and even rescue, we still take the lead from the experts such as the RSPCA and British Divers Marine Life Rescue, and won’t get closer than a couple of hundred metres.”

Although grey seals can often be spotted in the waters around Suffolk, the breeding colony at Orford Ness is thought to be the country’s first owing – in part – to its remote location, restricted access, and very limited disturbance. 

The area, however, hasn’t always been conducive to successful seal breeding. From 1956 to 1972, Orford Ness was a site of Atomic Weapons Research. In the 1960s, in particular, it was the site for testing the next generation of nuclear weapons in a covert H-bomb test site. Since then, the area has been left to nature and today is a site abundant in wildlife including several species of nesting and wading birds, hares, Chinese Water Deer, and vegetated shingle. 

The first 200 adult seals arrived at the site in 2021 when visitor access was significantly reduced after an extended period of closure due to the Covid-19 pandemic. Since then, National Trust rangers have recorded an increase in numbers as the colony has grown.

Disturbance – which can include any human activity – is one of the biggest threats to grey seals on UK shores as it can cause them to change their natural behaviour.

Glen Pearce, Orford Ness’ property property operations manager, said: “We’re really happy to see new pups being born here at Orford Ness for the fourth consecutive year.

“Despite the seals’ arrival in 2021, we held off talking about them until earlier this year because we wanted to give them the best chance of survival. Being able to talk about them this year, in real time, is a great opportunity to share more about the species and to help people understand how their own actions and behaviours can impact them.

“Over the next six months, we’ll be sharing still and moving images from the colony – all recorded from a safe distance – as well as updates on the number of pups and observations from our weekly counts.

“In the meantime, we’re asking people to refrain from visiting out of season and to avoid using drones or other aerial equipment in the area. We really hope visitors will continue to work with us to help protect the colony, which is such a brilliant wildlife success story for Suffolk.”

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