Rare black-coloured seal pups among England's largest grey seal colony have been spotted by wardens.
Grey seals are born white and then shed their fur to expose a grey coat at about two to three weeks old.
But about one in 400 - known as melanistic seals - have a velvety black coat, the National Trust said.
Rangers at Blakeney Point in north Norfolk have seen 10 melanistic pups over the course of the winter's pupping season.
Melanism is the increased development of the dark-coloured pigment melanin.
Blakeney Nature Reserve, which is managed by the trust, is expecting a record-breaking baby boom of 4,000 grey seal pups this winter.
Due to the increase in the number of pups, rangers have changed the way they count the seals born at the breeding ground.
Rather than walking through the area and counting the newcomers, teams will monitor the number of pups in a particular area to give an indication of what is happening across the colony.
Due to the size of the colony, the National Trust deemed it unsafe, both for staff and for the seals, to walk through it.
It has become England's largest seal colony since recording its first pup in 1988.
In 2019, 3,399 pups were born there, compared with 25 in 2001.