There are sights that nobody sees for the first time. Sights such as the New York skyline, the Grand Canal, the Taj Mahal, Sydney Opera House and a tree in the north of Scotland.

The tree stands on the edge of Loch Garten in the Highlands. It was cut with a chainsaw and vandalised in 1963, and again in 1966, but it is still there, propped up and reconstructed. This is because the tree houses a miracle — one that has captured the imagination of the country.

It’s the osprey tree. It’s the place where the ospreys have nested every year for more than half a century. It’s the place the ospreys came back to, after it seemed that they had gone for ever.

Ospreys became extinct as breeding birds in this country in 1917. They were shot out, mostly for the sheer fun of the thing, though the idea of protecting fishing stocks played some part. That’s because ospreys live a life of outrageous spectacle: they feed by crashing into the water and coming out with a talon-full of fish.

But they came back. Persecution still goes on all right — stupid and selfish — but it is marginalised now. We no longer see it as our duty to rid the world of predators. And so, in the early 1950s, the ospreys made their impossible return. They came back on their own, without need for a reintroduction programme.

It was that most glorious thing: a second chance. The birds came back: and this time, they were cherished. The RSPB was at the forefront, of course, and they had a triumph of wild thinking. The knee-jerk response was to keep quiet about the ospreys, to tell no one, to guard them with your life and hope they manage to survive somehow. But — in what was to become the new orthodoxy for conservation — the RSPB decided to share them.

They made this rare, delicate, threatened bird available to us all. They built a place for the visitors to come and see the ospreys. In 1959, the first year, they received 14,000 visitors — and the ospreys did their stuff and produced young and flew off.

I was there a couple of weeks ago. On the blasted tree was a female osprey in all her finery, known as EJ. There she stood, white face, fierce black eye-streak, behind her the pine-ringed loch. This bird is 11 years old, and she has bred at Loch Garten since 2003. She was with a new male, who has been called Odin. He had brought fish to the nest early in the morning and was now off on another fishing trip.

EJ made a flight of a few feet to stand on a neighbouring tree and, like glove puppets, the horrible fluffy monsters of chicks raised their astonishingly ugly faces to the sky: I suppose another fish is out of the question, then?

This is a place that has known troubles. Apart from the damage to the tree, the nest was robbed by eggers in 1971. The osprey centre was destroyed by fire in 1990. The latest rebuild was in 1999, and it is as comfortable a way of watching enormous wild birds as you can find in the world: set up with telescopes and closed-circuit television cameras so you can see inside the nest.

People arrive in huge numbers; the millionth visitor came in 1985, the two millionth in 2003. There are now eight other sites at which you can see ospreys, and they are visited by 300,000 people every year. In that time, 86 chicks have been fledged from that Loch Garten tree: it seems they thrive on the attention.

The ospreys and the tree at Loch Garten have become a tourist honeypot, reflecting the hunger that we have for wild creatures. The poetry of the story of the bird that came back, the startling beauty of the birds themselves, their flamboyant way of hunting, their spectacular flight, their faithfulness to their place, to their tree: all these things bring people to the ospreys.

There are now about 200 of the birds in Britain, with the odd pair now nesting outside the Highland heartland, in England and Wales. I once saw one when I was rowing a boat on a river in Norfolk, nearly capsizing the damn thing in exultation. But they are birds to exult over. Birds that offered us a second chance. Birds that tell us of our own deep need for the wild. Birds that tell us that sometimes, even optimism is not too ludicrous a stance.

Live webcam link to Loch Garten ospreys: www.rspb.org.uk/webcams/birdsofprey/lochgartenvideo.asp