Concerns have been raised by the Royal Society for the Protection of Birds (RSPB) about the possibility of bird flu after 38 birds were found dead at an internationally-important nature reserve in Suffolk.
The confirmed count of dead birds at RSPB Minsmere includes common terns, sandwich terns and black-headed gulls.
All three of these species are on the amber list, meaning their conservation status is of moderate concern.
An RSPB spokesman said: "We are aware of a number of dead and unwell birds on the Scrape at Minsmere.
"We have informed Defra [Department for Environment, Food and Rural Affairs] of this, and we are waiting for them to examine the dead birds."
The coastal nature reserve is taking a precautionary approach in order to protect staff and volunteers, which means they will not be removing or moving dead birds.
The spokesman added: "We know that this will be distressing for visitors.
"We will follow all recommendations if a positive test for avian influenza is returned."
The RSPB has been concerned, both locally and nationally, as the latest strain of bird flu is particularly infectious and deadly.
It said: "Seabird populations such as these are under numerous pressures across the board and this is one more significant problem.
"We are hoping that Defra will now act quickly, safely remove the carcasses and confirm if these deaths have been caused by avian influenza."
A Department for Environment, Food and Rural Affairs spokesman said: "We are aware of a number of wild bird deaths reported from several locations in England.
"These deaths are currently under investigation as part of the Animal and Plant Health Agency's (APHA) ongoing wild bird surveillance programme.
"APHA will arrange collection of some of these birds and test them to help us understand how the disease is distributed geographically and in different types of bird - not all birds will be collected."
On all reserves, the RSPB is encouraging the public not to approach any sick or dead birds, to wash hands and footwear thoroughly when returning from their walk and to keep dogs on a short lead to reduce chances of contact.
Visitors are asked to report any sightings of sick or dead birds on the reserve, including details such as quantity, species and location, to the Minsmere Visitor Centre.
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