Bird rescue: Struggle against mystery oil in Dorset
31 January 2013 Last updated at 22:43 GMT
Hundreds of birds covered in a sticky substance have been washed ashore on the south coast of England.
The birds, which are mostly guillemots, have been discovered on beaches from Hampshire to Cornwall.
Some of the birds have died while others have been taken to rescue centres.
Experts believe the birds could be covered in some sort of vegetable or palm oil but are yet to identify it.
Robert Hall reports.