SCIENTISTS have yet to establish where more than a dozen dead swans were poisoned.

The grim discovery was made at Fairnington, near St Boswells, around the turn of the year.

But tracking systems showed they had travelled almost 1,000 miles in the days before their deaths.

Between December and January a total of 16 whooper swan carcases were found in and around the hamlet.

Post mortem tests found high-levels of lead poisoning in five of the birds with inconclusive results from the others.

South of Scotland MSP Colin Smyth raised his concerns in Holyrood.

The Labour list member said: "I want too ask the Scottish Government what steps will be taken to ensure that there are no repeat episodes similar to the mass death of whooper swans in the Fairnington area of the Scottish Borders."

The Parliament was told that the swans had migrated from Iceland and that the high levels of lead could have been digested anywhere en-route.

Environment minister Roseanna Cunningham stated: "The cause of death for the remaining 11 whooper swans was not identified although, as they were found in exactly the same set of circumstances, it is highly likely they suffered the same fate.

"However, this could not be confirmed during post mortem due to the advanced state of decomposition in most of the carcases.

"It is not possible to say where and when the swans ingested the lead."

Ms Cunningham added that none of the birds had been shot and there was nothing to suggest any foul play involved in the deaths.

She added: "There is no evidence to suggest the swans ingested the lead over a wetland area, although this remains a possibility.

"There is no wildfowling undertaken at the location where they were found."