New tactics are being adopted in an attempt to prevent an outbreak of bird flu in Britain.
There are fears that bird flu could arrive through migrating birds
A surveillance operation to check for infected wild birds will concentrate on favourite spots of migrating waterfowl.
These zones include the northern and West Midlands, the south coast, parts of the West Country, Anglesey, eastern Scotland and much of East Anglia.
The operation will also focus on poultry farms which could be at risk from the H5N1 bird flu virus.
The programme is being introduced in time for the start of the migration season of water birds, and has three elements:
- testing of live birds which are then released
- testing shot birds - shot as part of legal fowling practices
- testing certain species of dead wild birds found in designated areas
Species considered to be most at risk of introducing bird flu including ducks, geese, swans, gulls and waders, are more likely to be targeted.
Martin Fowlie, of the RSPB, said the surveillance operation was being carried out at all the society's reserves around the country.
"We're sending our wardens out to look at and survey different wetlands - looking for dead and dying ducks, basically," he said.
BBC rural affairs correspondent Tom Heap said the public were still being encouraged to report dead water birds.
But Defra said the likelihood of a dead wild bird found to be infected is very small.
Debby Reynolds, the UK's chief veterinary officer, said: "This new targeted strategy ensures that our operation is as sharp as possible.
"One thing that never changes however, is the need for us to work in partnership with poultry farmers, wildlife experts, scientists and the general public to keep the risk to a minimum," she said.
In August, Britain's deputy chief vet Fred Landeg expressed concerns over bird flu being passed to farm birds by migrating birds.
Earlier this year, thousands of birds were culled after a bird flu strain was discovered on three farms in Norfolk.