Illegally dumped waste from a septic tank may have been to blame for the deaths of 32 swans in Dunfanaghy.
Rangers examine the dead swan found in Mullaghduff yesterday
Investigators have discovered the waste in a field next to New Lake where the birds were found last weekend.
It is believed the material could have seeped into the lake and gradually killed the birds over the past month.
Pat Warner, regional manager of the National Parks and Wildlife Service, said this is the most likely cause of the deaths.
The carcasses of the birds have now been sent to the Department of Agriculture’s Regional Veterinary Laboratory in Sligo for analysis.
It will take at least a week for those tests to come through and to show what killed the birds.
As well as the discovery of 32 swans in Dunfanaghy, a further three birds were founds 30 kms away in Mullaghduff.
Wildlife officers believe the three birds may have flown from the original flock in Dunfanaghy and then died.