The revelation comes in two new books which examine who owns Scotland. The authors have searched through ancient deeds and estate agents' sales brochures to compile the most detailed picture of land ownership for a generation.
They show that most lairds no longer hail from Britain's tweed-clad huntin', shootin' and fishin' classes; these days your local feudal overlord is more likely to be a self-made continental millionaire or an entrepreneur from Dubai, Egypt, Malaysia, Hong Kong or plain old America.
The findings have sparked a political row north of the border. Many of the new lairds are absentee land-owners who, environmentalists claim, neglect Scotland's greatest asset - the land itself.
Nationalist MPs and crofters, frustrated by the failure of Westminster politicians to bring Scotland into line with England and other European nations by abolishing feudal structures and regulating land use, are drawing up plans to limit foreign land ownership and introduce environmental codes for all estates. They want ministers to compile a full public Land Register.
The two books, Who owns Scotland now? and Who owns Scotland, update John McEwen's ground-breaking attempt to sketch Scotland's land-owning geography 30 years ago. His study revealed that ancient British families dominated the hills, straths, glens and islands, controlling lucrative salmon beats and deer stalking from the Borders to Barra.
Since the Fifties and Sixties, however, the decline of some of the most distinguished and notorious names in the Highlands - the clan chiefs of the Frasers of Lovat, the Sutherlands and the Wills tobacco family - has paved the way for new owners to take to the hills.
Andy Wightman, author of Who owns Scotland, which will be published in April, explains: "Some of the old landowners like the Duke of Buccleuch, the Duke of Atholl and Cameron of Lochiel have survived. Their old money is still good and some of their estates have expanded. But other families have fallen on hard times and a new group of landowners has stepped in swiftly to take their place. Many of these are from overseas and as they move in, a new pattern of land ownership is emerging."
All over Scotland there are now glens and peaks that are forever Swiss, Danish, Malaysian, Middle-Eastern and American. One year ago the whisky distilling MacDonald-Buchanan family sold off the Strath Conon estate in Ross-shire, which they had held for three generations. The new kilted monarch of the 50,000-acre glen is Kjeld Kirk-Christiansen, who runs the huge Danish Lego corporation.
On the Hebridean island of Eigg, Keith Schellenberg, the fantastically wealthy former captain of Britain's Olympic bobsleigh team who once described "his" islanders as "drunken, ungrateful, lawless, barmy revolutionaries", sold up last year as part of a divorce settlement with his second wife Margaret Udny-Hamilton. The new laird is the chain-smoking, beret-wearing "fire" painter, "Professor" Marlin Eckhard Maruma from Stuttgart.
Visitors to Queen's View in Glen Avon, where Queen Victoria used to look out on her Royal fiefdom, now look down on land owned by the mysterious businessman behind the Kuala Lumpur-based Andras conglomerate. He bought the 40,000-acre estate, once owned by the Wills family, for pounds 6m last year.
Some ancient aristocratic families have hit the buffers in spectacular fashion. The Lovat Frasers' downfall began when three family members died suddenly; one was gored to death by a buffalo in Tanzania, another collapsed while hunting, and the third succumbed to old age.
Others have been crippled by debt. Losses in the Lloyd's insurance market forced Lord Kimball, a Lloyd's Name, to sell the 47,000-acre Altnaharra estate in Sutherland. Whatever the cause, the result is that fewer than half of the big Highland estates are owned by Scots.
"It's a dramatic change," said George Rosie, the veteran Scottish land- reform campaigner. "In the 19th-century, parliament passed an Act allowing foreigners to buy any property. As Britain was then the biggest rooster on the midden, the idea that any foreigner would be able to buy into Britain was risible. But now there are millions of wealthy foreigners and Scotland is ripe for the plucking. And plucked we have been."
Some of the new wave of overseas buyers enjoy good relations with locals and have earned environmentalists' praise for their land management practices. Paul van Vlissingen, the Dutch businessman whose "holiday cottage" is the eight-bedroom white-washed Letterewe lodge on the banks of Loch Maree in Wester Ross, has helped to fund a new swimming pool and re-introduced native woodland on his 80,000-acre estate.
Other lairds, however, have been accused of barring access to walkers and neglecting the natural environment. "Mountain Closed" signs have recently appeared on estates north of Ullapool. In Perthshire, His Excellency Mahdi Mohammed Al Tajir, from the United Arab Emirates who owns the Blackford Estate, home of Highland Spring mineral water, has been accused of abandoning farms on the slopes of the Ochil Hills.
Nationalist politicians say Scotland's free market in land - it is one of the few countries in Europe which allows wealthy foreigners to buy up unlimited amounts of land with no questions asked - has created a "land lottery". While far-sighted landowners are welcome, they say new measures should be introduced to limit the size of their holdings and to remove those who neglect their land.
Later this year, the Scottish National Party, which has set up an independent land commission, will unveil new proposals. Labour, too, has pledged to use a devolved Scottish parliament to introduce changes, and the Scottish Crofters' Commission is encouraging crofting communities to raise money to take over their marginal plots. Even Michael Forsyth, the Scottish Secretary, has jumped on the ox-cart, announcing plans to hand over millions of acres of government-owned crofting and forestry estates to small-holders. In Scotland, land is suddenly a political issue.
Dr James Hunter, a Skye-based environmental historian, said: "Land has moved up the agenda ever since the first crofters took over their land in Assynt 1992. That showed that land ownership patterns could change. Since then we have had controversies over the Knoydart estate and other Highland wilderness areas. The prospect of devolution - a Scottish parliament would address these long-standing grievances - has also concentrated minds."
The wind of change has unsettled landowners who will this week launch an unprecedented campaign to counter reformers' demands. At a special public meeting tomorrow, Graeme Gordon, convenor of the Scottish Landowners' Federation, which represents 4,000 estate owners north of the border who manage some seven million acres, will claim that the debate over land ownership is based on "dangerous generalisations and misleading assertions".
He will tell his audience that the "majority of landowners are committed custodians of natural heritage who provide jobs, housing and security for remote communities often at a personal financial loss".
As the prospect of a reforming Scottish parliament looms, the battle for the Highlands is only just beginning.