AT the age of 69, when most men are contemplating the quiet life, a Scottish explorer is setting off on a dangerous adventure, seeking one of the ornithological finds of the century.

Peter Gladstone, a great-grandson of the Victorian Prime Minister William Gladstone, leaves Scotland today aiming to become the first man to make a biological study of a distant and uncharted part of south east Tibet.

The Old Etonian and fellow explorer Charles Martell, 51, are leading a small expedition in an attempt to track down the pink-headed duck (Rhodonessa caryophyllacea), long thought to be extinct.

The remote area in Tibet where Gladstone thinks the pink-headed duck may still be nesting has been closed off to outsiders for decades during the Chinese occupation and it has taken at least a year to get clearance from the Chinese authorities.

They will travel 1000 miles east of the Tibetan capital Lhasa to marshy jungle pools after a period of acclimatisation in the Himalayas.

The lakes and marshland are at 14,000ft, but despite his years Gladstone is confident he is fit enough. A Cambridge rowing blue, he said: ''I have been going to the gym for a bit of exercise and I'm pretty fit for my age.''

The only available maps have been charted from outer space by US spy satellites.

At the family mansion Fasque, near Fettercairn, once the home of his politician ancestor, Gladstone said he also intends to indulge in a spot of yeti hunting. ''But that is just a fun thing. Put it this way, I don't think we will be necessarily taking one back as a fellow passenger on the plane if we find one.''