Dead birds scattered along the Sivash Bay in Crimea
© Grigory ProkopovDead birds scattered along the Sivash Bay in Crimea
A mysterious suspected 'bird flu' is feared to have wiped out thousands of seabirds.

Scientists are urgently investigating the cause of up to 7,000 deaths of black-necked grebes, sea doves, and gulls.

Disturbing videos show the dead birds along the Arabat Spit and Sivash Bay in the Azov Sea.

Harrowing footage shows one tragic bird still alive but with evident damage to its nervous system, losing its orientation.

"We have recorded the death of birds in large numbers, several thousands of them," said academic Grigory Prokopov of the Crimean Federal University, an ecologist.

The experts suspect a viral infection but locals have also raised the possibility of pollution damage to the seabirds, with reports indicating an excess of mercury in the area.

Worst hit appears to be the black-necked grebe, a migratory bird.

Specialists from the Federal Centre for Animal Health are now working at the spot, and analysis of the dead birds will be carried out.

The authorities in Crimea have not yet commented on the suspected bird flu on Europe's southern flank.

A report said the dead birds were" scattered all over Sivash Bay".

It suggested an infectious disease is the most likely cause, but it could also be "both poisoning and the ecological situation".

It added: "An excess of mercury was recorded in this area."

But Mr Prokopov thinks a new bird flu is the most likely cause.

"Most likely, this is not poisoning," he said.

"The behaviour of a bird I managed to observe indicated it was clearly sick and died.

"This is very similar to damage to the central nervous system. Most likely, this is some kind of virus.

"But the final conclusion must be made by veterinarians."