Six killer whales sighted off the Forth are believed to have come down from Icelandic waters to hunt.
Whale-watchers were able to identify the orcas off the Isle of May last Thursday because one of the females has a distinctive notch in her dorsal fin. The species, which rarely ventures this far south, was last spotted off the island almost 20 years ago and this is only the third time orca have been seen in the Forth.
The pod – a bull, four females and a calf – swam down via Caithness to hunt seal pups and spent about an hour close to the island, to the delight of the 16 people watching from the cliffs.
They later swam towards a grey seal colony on the north of the island before heading off to deeper water on the Fife coastline but were later spotted off the Bass Rock.
Reserve manager David Steel was among those who saw the majestic creatures about 200 metres off the Isle of May close to the cliff-side.
He said: “They were very close in and we believe they were potentially checking out the island for grey seals.
“You can imagine the excitement and bewilderment from people here. I have never seen killer whales so I was absolutely ecstatic.
He added: “The shout went up across the island from the team and, as you could imagine, pandemonium let loose as people were running for binoculars in all directions.
“To see killer whales in the UK is a very special experience, but to see them in the Firth of Forth is even more special.”
Killer whales are more commonly spotted in the northernmost parts of Scotland, including the Shetlands.
Experts believe this pod is one of three main groups hunting in Scottish waters.
An isolated group has been seen in the Hebrides and is thought to feed on other marine mammals such as harbour porpoise and minke whales.
Meanwhile, fishing vessels off Shetland and Orkney often report orcas, which it is believed could be part of a larger Norwegian population.
A third group, which may be the pod spotted off the Isle of May, are thought to belong to the Icelandic herring eating population and they may be in the area hunting seals as their visits coincide with the seal pupping season.
Rob Lott, policy manager for Whale and Dolphin Conservation, said if this was the case then it would suggest orcas may be switching prey at certain times of the year. “It remains to be seen whether orca sightings are actually increasing in Scotland or whether there are just more people watching and in better weather conditions,” he added.
Sightings in the Firth of Forth are rare, with the last in January 2007 when a pod was seen swimming under the Forth Bridge and stayed in the area for several days.
Orcas are highly mobile and can easily cover up to 100 miles a day so whale-watchers have been urged to be patient. Males can grow up to 30ft long and weigh more than six tonnes, while females can grow up to 26ft and weigh up to four tonnes.