Environment Correspondent Tim Hirsch reports from Bempton Cliffs, Yorkshire

Fisheries minister Elliott Morley launched the project at a clifftop bird sanctuary in Yorkshire.

Seabird 2000 is the third census of the millions of seabirds that nest on the cliffs and rocks around Britain and Ireland each spring and summer.

However, new techniques that allow counting in even the most inaccessible nesting sites mean this survey will be the most accurate yet.

Dr Ian Mitchell and Chris Harbard explain what they believe the survey will achieve

It should give environmentalists a near-complete picture of how seabird species are faring at the start of the new milennium. Carried out by an army of skilled volunteers and experts, the survey will show up trends in bird population patterns at a regional and at a national level.

It is also likely to provide clues about how birds are affected by overfishing. It might even be possible to see the effects of global warming, as changes in sea currents hit the food supplies on which some birds rely.

Breeding pairs

"We've got 28,000 miles of coastline to cover," said Seabird 2000 Project Co-ordinator Dr Ian Mitchell. "We're really interested in seeing how many species are actually breeding, not just the numbers of birds using the cliffs."

He said the survey, once complete, would become an invaluable research tool.

Chris Harbard from the Royal Society for the Protection of Birds (RSPB) said many bird species act as indicators for the health of the oceans.

Overfishing is a threat to many bird species

He said kittiwake populations at the Flamborough Head and Bempton Cliffs Special Protection Area, the location for the survey's launch, were dependent on fish stocks 30 miles out to sea. If overfishing depleted these stocks, it would have a devastating effect on kittiwake numbers, he said.

"The catalogue of seabirds will enable us to protect our coastlines and marine environment in a way that will enable the seabirds to thrive in the future."

The survey, which is costing £250,000, is funded by the Joint Nature Conservation Committee (JNCC) in partnership with the RSPB.