Death Swift for Pelicans Doused in 1990 Oil Spill

A new study of oil-doused brown pelicans cleaned and released after the infamous 1990 Huntington Beach oil spill paints a gloomy picture of their survival, showing that only a few lived more than one or two years after the incident.

The study underscores the damage that oil spills inflict on feathered wildlife and also raises questions about the long-term success of efforts to clean birds and return them to the wild.

Although such efforts often attract widespread media attention and provide hope that well-cleansed, well-nursed birds will survive, the study suggests that many rehabilitated birds remain weak, fail to breed and die prematurely after they are released in the wild.

“Rehab is not a panacea. Really, we ought to think about prevention,” said pelican expert Daniel W. Anderson, one of three UC Davis researchers who published the study.

In fact, Anderson said he was surprised researchers were able to locate fewer than 10% of rehabilitated pelicans two years after the spill, compared to 53% of unexposed birds.

“I expected to go out there and say, look at how well these birds survived,” said Anderson, a professor of wildlife biology at UC Davis. But now, he reports, “we’re pretty sure most of them died.”

The spill, the worst in Southern California in two decades, occurred Feb. 7, 1990, when the American Trader tanker ran aground. Ruptured by its own anchor, it spilled more than 400,000 gallons of Alaskan crude, polluted 15 miles of beaches and killed at least 1,000 birds.

Legions of volunteers searched Orange County’s beaches for oil-soaked birds that were then nursed by animal experts and released in the area.

Anderson and his colleagues set out to chart the welfare of California brown pelicans, an endangered species, after their release.

They outfitted 112 rescued pelicans--91 from Huntington Beach and the remainder from a smaller San Pedro area spill a year later--with markers or radios and then released them.

The results of the tracking are published in the current issue of Marine Pollution Bulletin.

“Our results and a growing number of other studies indicate that current rehabilitation techniques are not effective in returning healthy birds to the wild,” said the article by Anderson and fellow UC Davis researchers Franklin Gress and D. Michael Fry.

Before their release, all of the pelicans in the study were cleaned and received medical treatment and abundant food, and Anderson praises the quality of rehabilitation efforts.

Meanwhile, additional pelicans that were not in any spills were collected in Ventura County and then released to serve as a control group.

The two groups of birds followed distinctly different paths after their release.

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Two years after the Huntington Beach spill, only eight of 91 rehabilitated pelicans could be accounted for, compared to 10 of 19 unoiled pelicans, researchers found.

The birds were not tracked after 1992, but Anderson reports the sighting of one sickly looking rehabilitated pelican about two years ago on a Long Beach breakwater.

While researchers do not know the fate of every bird in the study, Anderson calculated Friday that based on existing knowledge of pelican survival rates, up to 15% of the oil-exposed birds survived after two years, compared to 80% to 90% of the control birds.

The rehabilitated birds probably had swallowed oil, and studies have shown ingesting the substance can cause anemia, immune problems and tissue damage in birds, he said.

Exposure to oil appeared to change the pelicans’ breeding habits.

The oil-soaked pelicans failed to breed a year later.

In the two years after the spill, the oil-exposed birds showed no inclination to breed and generally were not found in regular breeding colonies.

Anderson’s study was funded by the U.S. Department of the Interior Mineral Management Service and the state Department of Fish and Game’s Office of Oil Spill Prevention and Response.

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Its findings are similar to those reported in April by independent ornithologist Brian E. Sharp in the journal Ibis. After assessing the survival of oiled and cleaned seabirds, Sharp concluded that the cost and effectiveness of such rehabilitation efforts should be reexamined in view of findings of a low post-release survival.

“It just so happens that the data tells you, startlingly, that these birds just aren’t surviving once they’re cleaned,” Sharp said in an interview Friday.

Meanwhile, volunteers in cleanup efforts as well as the general public are left with the mistaken notion that oiled birds that are cleaned and released can resume a normal life, he said.

“These volunteers are not being told, the public’s not being told, that these birds are not going to survive,” Sharp said.

Jonna Mazet, wildlife veterinarian with the state Department of Fish and Game, is more optimistic about the success of rehabilitation, saying that the science has matured since the Huntington Beach spill and the 1989 Exxon Valdez disaster.

“Our methods and procedures have changed by leaps and bounds since those oil spills,” said Mazet, director of the state Oiled Wildlife Care Network. For instance, cleaning and stabilization techniques have been improved, she said.

But the best cure of all is prevention, Anderson said.

“Really, the way to solve all these problems,” he said, “is just not to have any more oil spills.”