Soaring and gliding gracefully over the water, pelicans are a familiar sight around San Francisco Bay. Two types of pelicans live here, the California brown pelican and the American white pelican. They arrive and depart at different times of year.
California brown pelicans (Pelecanus occidentalis californicus) are most common around the central and northern bay. One of the bay’s largest birds, they are gray-brown in color, with big bills, curved necks, and wingspans that average seven feet. Brown pelicans plunge-dive head first into the water from as high as 65 feet. Underwater, they open their bills and fill their huge throat pouches with up to three gallons of seawater and fish. Then, back on the surface, they strain the water out the sides of their mouths and swallow their catch.
During the 1800s, brown pelicans were so plentiful on the island of Alcatraz that a French observer said when they rose in flight together, it created a wind like a hurricane. But by the early 1900s, most had been killed for their plumes, and their numbers had dwindled.
The brown pelican population slowly recovered until the 1960s. Then, the use of the pesticide DDT again caused the species’ numbers to plunge. The pesticide caused the shells of the birds’ eggs to thin, preventing the embryos from maturing. In 1970, the brown pelican was listed as an endangered species. After DDT was banned in the 1970s, the population of brown pelicans gradually made a second comeback, and the bird was removed from the Endangered Species List in 2009. There are now about 10,000 breeding pairs in California. However, brown pelicans are still threatened by serious health problems that may be caused by toxic algae.
Brown pelicans spend summer and fall in San Francisco Bay, then they fly south to breed in Mexico and at the Channel Islands along the southern California coast. They are also seen occasionally around the South Bay during winter.
Around the South Bay, however, the American white pelican (pelecanus erythrorhynchos) is much more common, especially at the Don Edwards National Wildlife Refuge. White pelicans are even larger than brown pelicans, with wingspans averaging nine feet. They are snowy white, with black flight feathers visible only when their wings are spread. These birds nest and breed at inland US lakes during spring and summer, then spend late fall and winter in the Bay Area.
Unlike brown pelicans, white pelicans don’t plunge-dive. While swimming, they catch fish by scooping water into their pouches, then strain out the water and swallow the fish. Sometimes, groups of white pelicans form a semi-circle, slap their wings against the water, and drive a school of fish closer to shore, where the fish are easier prey.
Both white and brown pelicans are vulnerable to injury or death if oil is spilled into San Francisco Bay. If these birds eat fish that have been swimming and feeding in toxic pollution, pelicans can also accumulate a heavy load of toxic substances in their bodies. For the safety and health of pelicans and all Bay wildlife, Baykeeper works to stop toxic industrial pollution in the Bay, and for the Bay to have the strongest protections from oil spills.
Photo of white pelican by Joan Robins; photo of brown pelican by John ‘K’ (Flickr/CC)