An emergency environmental team were called out after fly-tippers dumped engine oil at a Birmingham beauty spot endangering hundreds of wild birds.
Council officers were alerted to reports of several birds covered with oil in Witton Lakes which is a popular breeding ground for swans, coots and other waterfowl.
They immediately called in RSPCA officers and the Environment Agency to help with the clean-up operation which took place throughout the weekend.
Birmingham city council’s biodiversity officer Dr Stefan Bodnal said swift action by all agencies had prevented a major disaster.
He said: “All of the organisations worked together quickly to prevent this from becoming a major disaster. It was a serious situation but we managed to contain it and stop it from becoming really nasty.
"There are hundreds of birds in the lake during winter, if we didn’t deal with the spread of the oil quickly things could have been a lot worse especially because it was engine oil which is full of toxins. This is malicious vandalism.
“There was a considerable volume of oil dumped, more like a barrel. It spread into quite a large area. The amount oil was evident from what was seen on the birds. The oil gets into the feathers and removes their protection which can lead to death.”
The RSPCA said six Canada geese, swans and coots were rescued from the lakes. Other wildlife including a mallard duck covered in oil were spotted.
Judith Haw, from the RSPCA, said: “There maybe many more affected but these are the ones officers were able to catch and treat.
“Three of the Canada geese were worst affected and it is unclear at this stage whether they will survive.”
Emily Poyser, from the Environment Agency, said the culprits can be traced and prosecuted.