A RESCUE operation was launched after more than 100 seabirds appeared on Dorset beaches covered in a mystery substance.

Wildlife officers and wardens from the RSPCA, Dorset Wildlife Trust and the Portland Bird Observatory took the birds - a group of guillemots and razorbills - into care, which were found from Portland to Lyme Regis.

Concerned members of the public raised the alarm and the worst affected birds were taken to the RSPCA centre at West Hatch in Somerset where two had to be put down.

Members of the public are being warned not to handle the birds until the substance is identified.

A spokesman for Dorset County Council said: “While the substance is being identified, agencies are urging people to avoid coming into contact with the birds and to keep pets away from the shoreline.”

Martin Cade, of the Portland Bird Observatory, said: “A lot of them are absolutely plastered in the stuff, it's like a sticky, glue-like substance.

“Some of them were well enough to waddle away when we approached, but others were sitting looking very sorry for themselves, so we collected them up and handed them over to the RSPCA.”

Most of the birds were found around Portland and Chesil Beach, with others spotted along the coast as far as Lyme Regis.

A spokeswoman for Dorset Wildlife Trust warned the public to leave the rescue operation to the experts.

She said: “We are doing what we can, but we don't know what this substance is, so it is best left to the experts who are wearing gloves.

“It is a very worrying and distressing thing to happen. This type of bird, known as auks, is struggling with their population anyway, so we don't need this kind of problem.”

Margarine is being used to absorb the substance, which is reported to have caused lesions where it has come into contact with the birds' skin.

Investigations are ongoing to find out what the substance is, but experts believe it is vegetable-oil based.

The birds dive for food, which Martin believes may be how the group came across the substance.

He said: “You see them out on the water fishing or swimming about, and they must have got into a slick of something, perhaps from a ship.

“It must have covered quite an area.”

He added: “They can't fly because they are covered in it, so they all come ashore to sit on the beaches.”

If anyone spots an affected bird or animal, they should report it to the RSPCA on 0300 1234 999.

N rachel.stretton@dorsetecho.co.uk Wildlife assistant Paul Kennedy, who works at the West Hatch centre, said: “We had about 35 brought in on Wednesday and then about 80 more on Thursday.

“One or two sadly had to be put to sleep, because they had severe injuries, probably from bashing against rocks as they came ashore.”

He added: “We have been using margarine as a solvent, which seems to be working, and then washing them as normal.

“They look like they have had a pretty rough time, and where it has come into contact with their skin, it seems to have pulled off the surface layer.

“Hopefully we will not see the problems we have had in the past where it has affected their internal organs.”