The number of seabirds found dead after being covered in a sticky, oily substance on the Westcountry coast is continuing to rise.
At Chesil Beach on Friday 200 birds were found dead and a further 162 were rescued by the RSPCA.
The RSPB said it was a large increase on the previous day when around 100 were rescued and 15 were found dead.
Thousands of seabirds have been washed ashore along the south coast between Cornwall and West Sussex.
Many of the seabirds have been taken into care at the RSPCA West Hatch wildlife centre in Taunton, Somerset.
The glue-like substance which coats the birds' feathers has been identified as a refined mineral oil by scientists at the Environment Agency.
The oil, which is a colourless, odourless substance and is related to petroleum jelly, may have been discharged into the sea accidentally or deliberately.
Dorset Wildlife Trust (DWT) said today's wind conditions mean they cannot reach many birds, which will result in increased numbers dying.
A spokesman said: "As of 11am today, Marc Smith our DWT Chesil Officer has reported that a change in the wind has limited the numbers of seabirds seen along the nearby coastline. The north west offshore wind is now blowing many seabirds out to sea which will limit the rescuers ability to recover the affected victims of the toxic man-made mineral oil.
"This will also increase the overall number of fatalities.
"So far, between the Chesil Centre and the Cove, birds recovered include 10 dead and two alive."
The contaminant is sticking the birds wings to their bodies and sticking stones and other debris to them, meaning the birds are unable to move or forage for food.
Discussing the toxic substance, Tony Whitehead of the RSPB told the BBC: "Where it came from we don't know. We need to do a lot more testing on this substance to try and trace it back to its source.
"There are people speculating it could be from a ship, that's possible, but we just don't know yet.
"We need to look at what's happened and, if appropriate, take legal action and also frankly to shame the people."
Members of the public are being warned not to try and catch sick seabirds.
Mr Whitehead added: "Please don't try and catch them.
"The reason for that is you might scare the birds back into the sea. A lot of these birds are getting very weak, very emaciated now, they need to be in proper hands.
"Call the RSPCA and they can arrange collection and get them to the wildlife hospital."
At the West Hatch Animal Centre in Taunton, staff are using margarine and washing up liquid to clean the substance from the bird's feathers.
Peter Venn, manager at West Hatch, said: "What we are hearing are reports of birds showing up on the Sussex coast, so that may mean that the weather is pushing them more easterly.
"Everything is certainly not over by any means. There were quite a lot of birds dead in the water this morning.
"What we don't know is what is still out there."