One of the reasons we don't see usual things is because we don't see unusual things even when they are in front of us. In fact, the time is ripe for a doctoral-level thesis on the subject of perception as it affects birdwatchers and all people who look at wild things.

We see what we expect: that's how the brain works. The eye brings us rough approximations and the brain fills in the gaps. That means, for example, that the more you look at birds, the better you are at seeing birds, because your brain gets better at filling in gaps. Layman's descriptions are always hard to make sense of because they come from people who have not educated their brains about birds.

And so I looked out across Island Mere at Minsmere, the RSPB nature reserve in Suffolk, and I just didn't see it. My eye bounced off it, as if the brain rejected the sight. We don't get stuff like this round here, therefore you didn't see it. Then you look again and you are startled by what you have already seen - that's what a doubletake means.

I don't know how I could have missed it: it was a huge white thing; perhaps my brain pretended it was a swan. But it wasn't. It was tall and long-legged and lithe, holding itself with a thrilling stillness. When the doubletake was completed, I was looking at a great white egret, a bird that's not supposed to be here.

Rare birds are rare things; rarer still are the times I see one. This one is not rare as the twitchers count these things: they would call a great white a “tart's tick”, an easy bird you should have added to your list years ago. Half a dozen or so turn up here most years, usually singletons; there were 264 records between 1958 and 2004.

If you cast parochial views aside, great white egrets are not rare at all: I have encountered them all over the world, in Asia, Africa, America, Australia and southern Europe. This bird, the coloured rings proclaimed, was French. But under an overcast sky, in a biting East Anglian wind, he gobbled fish with immense voracity and looked infinitely capable of founding a British colony. All he needed were a few like-minded souls.

Hosepipe necks

There is a strange thing that these egrets do. They put a most alarming kink in their necks, like a twisted hosepipe, so they look as if they have broken their necks. When they do this, they appear alarmingly like the Audubon pictures of themselves, a forced pose that doesn't seem entirely natural even though you are looking at the real bird.

They are fierce and methodical hunters, wading in deep water, staring at the surface as if they expected to burn a hole through it. They will assume a forward tilt at so sharp an angle you think they must lose their balance and topple over. Then they will hunt on the move, the head jerking forwards and back, like Bob Willis returning to his mark on the day he destroyed Australia.

This Minsmere bird had all the beauty of incongruity and that was once true of the little egret too. These birds, tiny by comparison, have over the course of a decade changed from occasional droppers-in to breeding residents, one you see all the time from train windows, birds that have visited my garden. Perhaps this pale Suffolk giant was planning a conquest.

Bush's albatross

It's time to hail George W.Bush, protector of the environment and guardian of birds that are - unlike my egret - not only genuinely rare, but also in serious danger of global extinction. Good of Bush. Have you noticed how world leaders so often greet the end of their time at the top by trying to become the leader they always should have been?

But let's not carp; rather say a quick hurrah because President Bush has joined the side of the angels, or at least the side of the albatrosses, and that's about as close as you are going to get to angels in this life. There are twenty-two species: eighteen are in serious trouble and ten of these are categorised as endangered or critically endangered.

The trouble with seabirds is that nobody sees them very much and no country has a clear responsibility to look after them.

The albatross is in danger of accidental death from long-line fishing, but there are other difficulties as well.

So an agreement has been drawn up among 12 countries, including our own; and President Bush has brought it to the US Senate for approval. “I believe the agreement is fully in the US interest,” he said. Good to know that his talent for glorious insularity hasn't deserted him.

It'd be nice if all these brave and good decisions were made by leaders at the dawn rather the dusk of their time in charge, but all good things must be cheered whenever they happen.

Besides, it's important for us all to know that what's good for the albatross is good for the United States of America.

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