Birdwatchers of the world unite to hear a dawn symphony

Some will be hoping for the mellifluous melody of the blackbird, others the liquid warble of the robin and still more the raucous, tuneless cry of the house sparrow. Whatever the preference, the promise of a memorable dawn chorus will be enough to attract hundreds of people this weekend for an annual communion that is drawing a growing number of avian devotees.

Some will be hoping for the mellifluous melody of the blackbird, others the liquid warble of the robin and still more the raucous, tuneless cry of the house sparrow. Whatever the preference, the promise of a memorable dawn chorus will be enough to attract hundreds of people this weekend for an annual communion that is drawing a growing number of avian devotees.

The International Dawn Chorus Day was just the plain old Dawn Chorus Day when a bunch of bird enthusiasts in the Black Country made a 4.30am start to appreciate it in 1983. It went global as enthusiasts from the United States to the Seychelles caught on and this year there will be around 100 gatherings at British locations as varied as Dorset and inner-city Birmingham.

Inevitably, the growing appreciation of the symphony - fuelled in no small part by the Royal Society for the Protection of Birds' Garden Birdwatch project which attracted 400,000 people last year - has begun to attract commercial spin-offs.

Two CDs, Dawn Chorus and Songs of Garden Birds have been recently launched, following the remarkable success of a disc produced by the British Trust for Ornithology, which sold thousands.

Bird ringtones are also popular, the yellowhammer, wood warbler and lapwing are among many that can be downloaded.

Blissfully unaware of all the excitement, the songbirds which deliver tomorrow morning will generally be males who perform to advertise for a mate and keep rivals away. He will leave gaps in his song to listen for replies, establish where any rivals might be and concentrate defensive efforts on those who may be in search of territory. Some species, such as great tits and chaffinches, will have a large repertoire of choruses to convince other males that all the territory is spoken for.

They sing at dawn simply because it is the best time of the day: the air is generally calmer and sound transmission is good. A dawn song is thought to be 20 times more effective than singing at midday.

Neil Wyatt, chief executive of the Wildlife Trust for Birmingham & the Black Country, which co-ordinates the event, said interest in birdsong is growing:"All sorts of little things have helped.... Here in Birmingham we have two peregrine falcons nesting in the Telecom Tower. It's really got people talking.

"The biggest down is that we never find out how many hundreds of people are taking part until they write to us, long after the event, with a record of what they have heard."

In 2001, the BBC demonstrated the international dimension of the day by playing extracts of bird and animal sounds between programmes, such as great reed warblers in Sweden, otters in Venezuela and trumpeter swans in Alaska.

"Our songbirds have been in decline due to loss of habitat and intensive farming," said Mr Wyatt. "The skylark has rapidly fallen in number by 52 per cent, the corn bunting by 84 per cent and the tree sparrow a staggering 87 per cent. This event is a reminder of their enduring importance to us."

Many of tomorrow's dawn chorus events are listed at: http://www.wildlifetrust.org.uk/urbanwt/html/idcd.html

Five songs to listen for in the morning chorus

ROBINS: have what might best be described as a twittering warble, or a warbling twitter, something like twiddle-eedee, twiddle-eedoo, sung usually from high up, surprisingly loudly.

WRENS : also have a long warble that is remarkably loud, given their tiny size. A shrill purring trill always occurs in the middle.

CHAFFINCHES: a descending, accelerating cheeping song ending in a distinctive flourish, sometimes portrayed as "chip chip chip, chooee chooee cheeoo".

GREAT TITS: a piercing repetitive call sometimes rendered as "teacher teacher teacher tee". Outside your window, can drive you nuts.

BLACKBIRDS: a rich, loud and musical song, pure, liquid and fluting. Also evident on spring evenings.