Dozens of seabirds have been found dead or dying on a beach in Orkney.

Many of the birds that have washed up at Scapa were guillemots, which spend most of their adult life at sea.

Naturalist Martin Gray said 24 birds he inspected were all emaciated, with the muscle mass in their wings and legs gone.

Gray said the young birds had likely lacked the experience to find food or cope with bad weather, adding: "It's very sad, but we don't see the birds that do make it so we have to hope there hundreds out there feeding happily."

Gray said he had checked only a sample of the dozens of birds washed up dead at the west end of the beach in Scapa Flow.

He said southerly winds would have blown the birds in from the sea.

The naturalist said guillemots developed strong muscles in their wings.

"All those big muscles they use for flight and diving were gone. The leg muscles were the same," he told BBC Radio Scotland's Around Orkney programme.

Gray said it was not possible to say for sure why the birds had not been able to feed, but added that nothing "sinister" was the cause.

"The best way I can describe this is it's just tough being a young seabird. They have the weather and the seas to face every day," he said.

"These young birds have simply died of inexperience.

"They didn't have the nous to be able to overcome a tough spell of weather."