The dorsal and tail fins of two basking sharks

Up to 60 basking sharks have been sighted by birdwatchers visiting an RSPB reserve on the Isle of Coll.

The sharks feed on plankton, tiny marine life, and can grow to 12m. Whale sharks are the world's biggest fish at 13.5m long.

A number of basking sharks have been seen with young calves passing the coast of Coll.

Sightings have been made by visitors on RSPB organised holidays on the island. They have also seen minke whale.

RSPB Coll Warden Simon Wellock has been amazed by the recent movements of basking sharks, which are normally seen in July and August.

Mr Wellock said: "It has been a quite remarkable few days on Coll with 37 basking sharks seen from the RSPB nature reserve alone and at least 20 others around the island.

"We would expect to encounter these kinds of numbers much later in the season and our recent visitors on the Hebridean Wildlife Experience have gone home with some unforgettable memories of some stunning wildlife."

Scotland's west coast is one of the best places to see basking sharks and whales in the UK, with Mull and the smaller islands of Coll and Tiree all offering good opportunities to see them.

Cally Fleming, from the Hebridean Whale and Dolphin Trust based in Tobermory, said the large numbers of sharks was good news.

She said: "The high number of sightings of basking sharks would indicate strong healthy plankton blooms.

"Our first basking shark sighting was reported to us on 21 April in the waters around north Coll, which is earlier than usual.