A sharp increase in dead seagulls found on three acres of Port of San Francisco land has city and state officials launching an investigation into why the birds are dying.
Occasional dead birds have shown up in years past at the land near Pier 94 just south of Cesar Chavez Street. In the past year, however, the number has taken an abrupt and mysterious flight upward.
Biologists from the Port of San Francisco, Animal Care and Control, the state Department of Fish and Game, and the Golden Gate Audubon Society are working together to get to the bottom of the matter.
Some of the birds were found with animal grease on their bodies, which soaks through feathers and makes them vulnerable to water and cold. Oiled birds commonly die of hypothermia, said Jay Holcomb of the
Fairfield-based International Bird Rescue Research Center.
Holcomb said that California Fish and Game biologists are investigating whether the birds may be somehow finding a way into the animal rendering plant owned by Darling International. The facility processes hundreds of millions of tons of animal fat, bones and other products each year into tallow, which is then sold to soap and cosmetics manufacturers or turned into animal food.
“Our feeling is it’s probably from there. Either it’s somehow getting into the water there or some birds get into containers,” Holcomb said.
Darling International did not return a call for comment for this article.
Not all of the birds found dead are covered in grease. Six of the birds have been sent to UC Davis for necropsies, and the results have shown a “hodgepodge of causes,” Fish and Game veterinarian Dr. Melissa Miller said. One bird died with oiled feathers, but others died of respiratory problems, infectious diseases and ingested rat poison, according to Port and city officials.
Golden Gate Audubon Society Executive Director Mark Welther said the organization has been restoring the plot of land since 2002.
“There has always been some gull die-offs on the property, but it just seems to have been increasing for the last year,” Welther said.
Holcomb said that while seagulls are not endangered, it’s important to investigate their deaths because they can be a harbinger of problems for other wildlife.
“Their status as common or rare is beside the point,” he said. “It’s about being a responsible steward. And if [grease] is going into the water, that’s a potential threat to aquatic life.”
An increase in the number of seagull deaths near Pier 94 has led to investigations.
65 Dead Western gulls discovered at site in past year
3 Acres of land where gulls were found
6 Necropsies performed on gulls
58 Typical wingspan of Western gull, in inches
2.2 Typical weight of Western gull, in pounds
2.5 million Pounds of fat, bone and other animal parts collected by Darling International each week and converted into tallow for cosmetics or animal food
Sources: International Bird Rescue Research Center, Port of San Francisco, San Francisco Commission of Animal Control and Welfare