Record number of grey seal pups born at ex-military weapons testing site

A record number of grey seal pups have been born at a remote shingle spit that was once a Cold War weapons testing site.

The number of seal pups counted at Orford Ness on the Suffolk coast this pupping season stands at 430 – almost double the previous year’s total of 228 arrivals.

The National Trust said the first 200 adult seals arrived at the site in 2021 when visitor access was significantly reduced following an extended closure amid the Covid-19 pandemic.

Numbers have increased each year since, with 25 grey seal pups born in the 2021-22 season; 66 in 2022-23; 133 in 2023-24, and 228 in 2024-25.

It is thought the seals initially spilled over from well-populated colonies in Norfolk, including at Blakeney and at Horsey, and are now Suffolk’s first breeding grey seal colony.

Matt Wilson, countryside manager for the National Trust’s Suffolk and Essex coast portfolio, said: “This year, our peak counts have included 803 adults and 430 pups, which is by far the highest numbers we’ve seen since the grey seals’ arrival in 2021.

“We’re now in the fifth consecutive year of successful breeding at Orford Ness, which means that some of the adults having pups this year would have also been born here in 2021 and 2022.

“It’s a good sign that the habitats are healthy, with enough fish stocks to keep them sustained throughout the winter, and the shingle ridge providing shelter from storms.”

He said Orford Ness closes from the end of October until the spring each year, which coincides with the seal pupping season.

“That means the likelihood of human disturbance is greatly reduced, which no doubt adds to their overall health and wellbeing and has so far helped them to thrive,” he said.

Tom Allen, ranger at Orford Ness, said the “bigger numbers, and typically wintry weather… can make counting difficult”.

He added: “Seals are wild animals and therefore move around, which occasionally means we’re unable to even get to some of their locations without the risk of disturbing them.

“We use a combination of telescopes and binoculars to help, which allows us to monitor the size and health of the colony from a safe distance, but as the colony gets bigger, it’s likely that our counts will become estimates rather than final numbers.

“We try to be as accurate as possible, but there is always a chance that some may have been missed.”

Female grey seals, known as cows, usually return to the same place each year to give birth.

Pups typically weigh around 13kg (two stone) at birth and are covered in thick white fur, which keeps them warm but is not waterproof.

They remain on the shore until they have shed this coat, revealing sleek grey fur underneath, by around three weeks.

They feed six times a day during this period and their weight will have trebled by the time they are weaned.