The Increasing Threats to Bay Birds

Oct 2, 2008
Sejal Choksi, with contributions from the Golden Gate Audubon Society
by Sejal Choksi, with contributions from the Golden Gate Audubon Society

Experiencing the San Francisco Bay’s amazing array of wildlife is one of the many pleasures of living in the Bay Area. Countless creatures call the Bay home, and millions of birds stop over during their annual migration. The San Francisco Bay is an important staging area along the Pacific Flyway, a migratory route used by more than 250 species of birds. These birds use the Bay to feed and regain strength during their migrations, which can span from Alaska to Argentina. The work of San Francisco Baykeeper and the Golden Gate Audubon Society protects not only the Bay and our local wildlife, but also species across North and South America.

You may already be familiar with one group of birds that frequent the Bay, diving seabirds. Seabirds like loons, cormorants, pelicans and grebes spend most of their time on the open ocean, seeking rocky islands or cliffs to nest and raise their young. They can be seen diving for food in the Bay. Perhaps the most recognizable diving seabird is the Brown Pelican, who breeds on rocky islands off the coast of southern California and Mexico and travels north to the Bay Area during the winter season. And if you’re walking along one of the Bay’s many marshes, you might even be able to spot the rarer American White Pelican, which has a large white body and dark wingtips.

The Bay is also visited by several waterfowl species, birds with webbed feet and waterproof feathers, like geese and both diving and dabbling ducks. Diving ducks are recognizable because their large feet and legs are further back on their bodies, helping them maneuver underwater; however, that feature also makes them awkward on land. Diving ducks in the Bay include the Ruddy Duck, Surf Scoter, Red-breasted Merganser and Common Goldeneye. In contrast, dabbling ducks have heavy bodies and a short tail, and their legs are in the center of their bodies, which allows them to easily walk on land. Dabbling ducks, like the Mallard, can be seen gliding in the shallow areas along the Bay’s shoreline or flying to and from the shallows to feed. 

Unfortunately, both resident and migratory bird species face increasing obstacles to survival in the Bay. The biggest threat is habitat loss – degraded shorelines and disappearing wetlands are eliminating the homes and breeding grounds of many of these birds. Today, the Bay has lost more than 90% of its historic tidal wetlands, the base of all aquatic life. Bird populations are also impacted by collisions with tall man-made structures and pollution from toxins and pesticides, as well as cycles of drought and food loss.

Additionally, birds are impacted by major pollution events, such as last year’s Cosco Busan oil spill. That spill released over 50,000 gallons of bunker fuel into the Bay, with devastating consequences for wildlife. The spill killed more than 2,000 birds in the San Francisco Bay and harmed countless other species and marine wildlife. Birds like the Surf Scoter had little chance of survival when their habitat and food sources – mollusks, fish, aquatic insects, and vegetation – became highly toxic.

This winter we will see many of the birds that survived the Cosco Busan oil spill return to the Bay, along with their new offspring. As the one-year anniversary of the spill approaches, Baykeeper and the Golden Gate Audubon Society are working to create a safer habitat for birds and other creatures in the Bay. We collaborated with Bay Area legislators to pass several bills in response to the oil spill, including one to provide more teams to rescue oiled birds in case of future spills. San Francisco Baykeeper and Golden Gate Audubon Society strongly support the Governor’s approval of the oil spill bills, all of which are badly needed to improve future oil spill prevention and response. 

The next time you cross the Bay on a ferry or walk along the Bay waterfront, take time to appreciate our avian neighbors and visitors. By joining San Francisco Baykeeper and the Golden Gate Audubon Society, you too can help protect these Bay birds and wildlife, and their critical habitat. 

To learn more about conservation efforts for the birds of San Francisco Bay, visit To help protect the San Francisco Bay from pollution, visit

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