A very British bird boom

Rare birds are arriving in Britain at a rate unprecedented in modern times, providing an almost weekly spectacle for the country's ever-growing army of twitchers.

A survey by The Independent on Sunday of data supplied by Birdwatch magazine shows that the past year has been the most remarkable one for sightings in decades. Normally, one or two bird species appear for the first time over Britain, but in the past 12 months, there have been six: a Pacific diver in Yorkshire, glaucous-winged gull in Gloucestershire and Wales, long-billed murrelet in Devon, yellow-nosed albatross in Somerset and Lincolnshire, masked booby off Portland in Dorset, and, this month, a great blue heron blown into the Scillies by a strong westerly weather system. The result is that the list of birds recorded in Britain which, at 577, is the longest in Europe is now even more impressive.

There have also been a rich crop of birds that, while not "firsts", are nevertheless what birders call "mega-rarities". BirdGuides.com, which provides information and other services to enthusiasts, monitors each year's "megas", and in 2007 has recorded 174 across Britain, by far the highest number since they started keeping a tally in 2001. These include birds that have only been seen a handful of times before in the UK, such as the American mourning dove, spotted in the Outer Hebrides, and a Madeiran storm-petrel off the Scillies.

These latest incomers join a number of striking species that were great rarities a few years ago but whose stays here are now both more frequent and lengthier. Unknown to the general public, cranes now nest in Norfolk, spoonbills have spent the summer in London, and the squacco heron, a squat, peach-coloured relative of our native bird, has been seen from Dorset to Suffolk. Great white egrets, heron-like birds with a wingspan of 5ft, now show up more often, and it is only a matter of time, says British Trust for Ornithology (BTO) population biologist Mark Grantham, before they start breeding here, as have their smaller relatives, the little egret.

The reason for the boom in sightings is the conjunction of far more and better-equipped bird-watchers and a warmer, more volatile climate. First, there are simply now vastly more people walking around the countryside with the interest and expertise to know, or suspect, a rarity. In the 1960s, the Royal Society for the Protection of Birds had 10,000 members. Today it has more than a million.

Crucially, they have access to superb, detailed field guides, MP3 players with the calls of every British species installed, plus powerful spotting scopes and digital cameras. The combination of these last two gives people a camera with, in effect, a 2,500mm lens. Digital photography has transformed rare bird identification, says BirdGuides.com's Fiona Barclay. Birders can use websites to instantly share pictures and get identifications confirmed by experts.

A photo of one of last year's firsts, the long-billed murrelet, was initially put on a Devon website by someone who did not realise what it was. Within hours, it was properly identified, word spread via birder-alert texting services, and thousands flocked to Dawlish in what was described as the "Twitch of the Century".

Ironically, the bird of the year came, tarried a day, and left without a single twitcher seeing it. Birdwatch magazine reported that, on 29 June, Hugh Harris of Brean, Somerset, saw a huge bird wandering around on his drive. He went shopping, and when the tired-looking bird was still there when he returned, he manhandled it into a box and drove it to an animal rescue centre nearby. They checked it over, kept it overnight, and then, the following day released it on Brean Down. A wildlife photographer took pictures, and only when these were studied was it realised that the bird was a yellow-nosed albatross. It was later seen in Lincolnshire.

Further browsing: To learn more about Britain's birds, common or rare, go to birdwatch.co.uk/website/