The swans fly 800km from Iceland to Scotland
The number of whooper swans migrating to Perth and Kinross has reached the highest level ever recorded.
RSPB Scotland said more than 350 of the birds, about 6% of the entire world population of whooper swans, have been counted at Vane Farm.
The numbers represents the highest in the reserve's 40-year history.
A harbinger of winter, the large birds migrate each year, along with pink-footed geese, from Iceland from about mid October.
Wardens at the reserve have also reported the presence of a water pipit, a rare visitor to Scotland, with an average of only 25 confirmed sightings a decade.
Although it does not breed in the UK, the water pipit is most often found in the winter in southern and eastern England.
RSPB Vane Farm warden, Chris Rodger, who carried out the count at the reserve said: "The waters around Vane Farm are positively bubbling with activity as over 350 whooper swans join up with the two thousand pink-footed geese roosting on the flood in front of the hides.
"The birds seem to be doing very well feeding on seeds and vegetation in the flooded fields surrounding Loch Leven."