Seabirds covered in a mystery waxy substance are being washed up along the South West coast in Devon, Dorset and Cornwall.
The RSPB has confirmed more than 100 birds had been taken to the West Hatch Animal Centre in Taunton but many more have been found dead.
The Maritime and Coastguard Agency said: "We have received reports of seabirds being washed ashore covered in a white waxy substance, from Cornwall to Portland, Dorset.
"We are liaising with the RSPB, RSPCA and Natural England to find out the extent of the problem, and if at all possible, to determine the source."
RSPB spokesman Tony Whitehead said: "The substance is not crude oil, but seems to be some kind of oil.
"We have had a few dead birds washed up over the past few weeks, but not this many.
"More being washed up could be a result of a change in wind directions."