(CNN) — Hundreds of birds were found covered in “goop” that authorities can’t identify, according to a spokesman for the California Fish and Wildlife Department.
“It’s a full-on mystery as to what happened,” the spokesman, Andrew Hughan, said. “We have no idea what they are coated in and I’m not sure when we will have the answer,” he said.
The birds were found in the San Leandro Marina on Tuesday. More than 300 were rescued and 100 are dead, according to Hughan.
Authorities are doing two lab tests to determine what the birds are covered in: one testing the water and another examining the birds to check if they died of hypothermia or were poisoned.
An oil spill has already been ruled out, Hughan said.
Julie Skoglund, an operations manager for the group International Bird Rescue, was flabbergasted by the mystery and the scope of the problem.
“I have been working here for 10 years and I have never seen anything like this,” she said.