East Bay Bird ‘Goo’ Mystery Narrows

A multi-agency collaboration by scientists investigating the "mystery goo" that affected more than 500 waterbirds in the East Bay in early January has identified the sticky substance as polymerized oil, most similar to vegetable oil.

The mysterious substance, ranging from an oily or gummy consistency to a hard varnish, coated East Bay waterbirds, severely limiting their ability to stay warm, float, fly and locate food. Investigators were unable to locate a pure sample of this material from a source, which in part is why the specific material has not been identified.

The "goo" was composed of a mixture of oils that contained polymers made up of fatty acids and triglycerides, and was most likely plant-derived. Petroleum products or animal fats were not detected through various chemical analyses. The presence of polymers (very large molecules made up of repeating smaller units) helps explain the gummy to hard nature of this substance.

"This may be as close as we get," said Daniel Orr, environmental scientist with the California Department of Fish and Wildlife (CDFW). "I wish we had more to go on, but without a pure sample or new investigative lead we may be at a standstill."

CDFW teamed up with other labs, including the U.S. Environmental Protection Agency, the National Oceanic Atmospheric Administration and the California Department of Public Health to share knowledge and compare test results in a multi-agency effort to identify the material.

International Bird Rescue (IBR) took the lead in caring for 323 live captured birds affected by the material. An additional 170 birds were found dead. The number of impacted birds that were not recovered due to predation or other factors is unknown. IBR was able to clean and rehabilitate 165 birds and release them back into the wild.

While it is well known that crude oil and petroleum products can harm wildlife, spilled or improperly discarded vegetable and fish oils can also exert harmful effects. When these substances come into contact with animal hair and feathers, vegetable and fish oils can cause loss of thermal insulation and buoyancy similar to petroleum products. Secondary effects can include hypothermia, starvation, drowning, predation, entrapment, suffocation, opportunistic infections and death.

The incident remains under investigation. If you have any information on the incident, contact CalTIP at 1-888-334-2258 or download the free CalTIP smartphone app. All reports are confidential.