Mystery goo that coated birds in SF Bay identified as mixture of oils 

click to enlarge State officials have identified the mysterious substance that coated and killed hundreds of birds in the Bay last month. - MIKE KOOZMIN/S.F. EXAMINER FILE PHOTO
  • Mike Koozmin/S.F. Examiner file photo
  • State officials have identified the mysterious substance that coated and killed hundreds of birds in the Bay last month.

A mysterious substance that coated and killed hundreds of seabirds in the San Francisco Bay last month was officially identified Thursday as a mixture of various oils.

The mystery goo that impacted birds primarily between Jan. 16 and 22 is believed to be a blend of non-petroleum-based fats or oils, but the exact product has not been determined and the source remains unknown as well, California Department of Fish and Wildlife’s Office of Spill Prevention and Response announced.

Non-petroleum oils include synthetic oils, such as silicone fluids, tung oils and wood-derivative oils like resin/rosin oils. Animal fats and oil, as well as edible and inedible seed oils from plants could also be included in the mixture, state officials said.

The material sullied into a sticky, thick consistency that was difficult to remove from the feathers of affected birds. Wildlife officials used baking soda, vinegar and dishwashing liquid to clean the rubber cement-like substance from their feathers.

The contaminant coated the seabirds - primarily surf scoters, buffleheads and horned grebes – by severely compromising their ability to stay warm, float, fly and locate food.

As of Thursday, 323 birds had been brought to the International Bird Rescue center in Fairfield for care, and more than 100 have been released back into the wild. The fish and wildlife department collected 170 dead birds from the shorelines, primarily in the East Bay, and another 131 birds died at the rescue center.

Scientists quickly determined that the goo was not polyisobutylene, or rubber, as well as petroleum, but the identity of the substance stumped authorities for several weeks. Agencies including the department of fish and wildlife, the U.S. Environmental Protection Agency, the National Oceanic Atmospheric Administration and the California Department of Public Health are assisting with the investigation.

Russ Curtis, a spokesman for the bird rescue center, said rescuers are relieved that laboratories are a step closer to identifying the actual substance and potentially finding the source.

“We’re still wondering where it came from and who dumped it,” Curtis said.

International Bird Rescue has shouldered the full cost of the response, and has spent an estimated $150,000 to clean and revive the birds to date, Curtis added.

Also on Thursday, six additional birds were released into the wild at Fort Baker in Sausalito, bringing the total number of freed birds to 110. Thursday’s release was particularly emotional for volunteers because a horned grebe nicknamed Gummy Bear was among those released. Gummy Bear was among the most contaminated birds upon arrival - a video posted online shows rescuers pulling away a towel that was stuck to the bird’s body from the goo.

Authorities are continuing to investigate the source of the contaminant. Anyone with information about the case is asked to contact CalTIP at 888-334-2258.

About The Author

Laura Dudnick

Laura Dudnick, a Bay Area native, covers education and planning for The San Francisco Examiner. She previously worked as a senior local editor for, and as the San Mateo County bureau reporter and weekend editor for Bay City News Service.
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