A mysterious sticky substance is killing seabirds along San Francisco's eastern shoreline, though by Sunday afternoon waters were nearly clear, according to reports.

Though the damage had already been done, with 20 seabirds killed and 69 others injured, San Jose Mercury News reported, the victims including surf scoters, buffleheads, common goldeneyes, and possibly hundreds more.

Eleven of the dead birds were shipped to a special Fish and Wildlife Department lab, where necropsies will be performed to determine exactly what kind of substance led to their demise.

"It might be there in microscopic levels, but to the naked eye you wouldn't see it," said Andrew Hughan, spokesman for the state department of Fish and Wildlife. "We were out there and investigated and now it's a matter of figuring out the results."

The clear, sticky, odorless substance spilled into the water at Hayward Regional Park in Northern California on Friday, and though it resembles an oil spill, experts say that it is not oil.

"I have been walking here for 10 years, I have never seen anything like this," San Leandro resident Pat Moore said. "It's sad. You see these energetic birds diving into the bay and popping back up. Then you see these birds dazed and struggling just to drag themselves onto land."

The dubious goo appears to hinder the ability of the birds' feathers to protect them from hypothermia, as well as prevents them from flying.

Rescuers have been working over the weekend to clean up some still surviving birds, though soap, baking soda and vinegar have thus proved ineffective against the silicone-like gunk, which is stuck deep under the birds' feathers.

"Not only is it environmentally irresponsible, but for it to affect this many animals is very upsetting," Julie Skoglund, operations manager at the International Bird Rescue, told CBS News.

Hopefully the necropsies - the results of which won't be available until Tuesday at the earliest - shed some light on this sticky situation. Until then, the seabirds will continue to be treated in the hopes of finding an answer.

The rescue team is asking for donations to help fund their effort to save the birds and find out what the mystery substance is - and who's responsible for the spill.

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