To a long list of predators and threats, the western snowy plover, a sparrow-sized bird that nests in sandy beaches on the Sonoma coast, has a new nemesis: climate change.
The little brown, black and white shorebird is among the feathered species at risk from rising seas due to climate change, bird experts said.
"They are already in trouble," Gary Langham, director of bird conservation for Audubon California, said of the plovers, a threatened species since 1993. "Climate change makes it ten times worse."
Two other local birds — the black rail, a rare fowl that nests in tidal marshes at Bodega and Tomales bays, and the black oystercatcher, often seen at Bodega Head — are specifically named in a new report, "State of the Birds 2010."
Also at risk is the common murre, which breeds on coastal rocks at Point Reyes in Marin County.
The report, released by the U.S. Fish and Wildlife Service and 12 other public and private agencies, says that hundreds of bird species face habitat loss and disruption of food supply from climate change.
It calls for improved bird monitoring programs to assess the impact of climate change, along with increased habitat conservation.
The report says that climate change is "altering the natural world as we know it," but does not delve into the controversy of global warming.
Of 84 coastal bird species nationwide assessed in the report, 74 species — nearly 90 percent — were deemed to have medium to high vulnerability to climate change.
America's birds have been impacted by hunting, pesticides and human development for more than a century, Interior Secretary Ken Salazar said in releasing the report.
"Now they are facing a new threat — climate change — that could dramatically alter their habitat and food supply and push many species toward extinction," he said.
A rising sea level, one aspect of climate change, could eliminate beaches where the snowy plovers nest and marshes that harbor the black rails, said Glenn Olson of Audubon, one of the agencies collaborating on the "State of the Birds" report.
For the common murre, once abundant on the California coast but devastated by a 1986 oil spill, the prospect of increased fluctuation of ocean temperatures could affect breeding, Olson said.
The black oystercatcher, which nests among coastal rocks, could be displaced from breeding sites by a rising sea level, Langham said.
Since much of California's coastal area has been developed, shoreline birds can't necessarily move to new habitat, he said.
"They run out of real estate real quickly," he said. "You can't just transplant a salt marsh and have everything work out."
The snowy plover, found locally at Salmon Creek, Bodega Harbor and Doran Beach, faces a host of hazards. It nests in the sand, barely visible to naked human eye, but vulnerable to falcons, raccoons, owls and other predators, as well as humans and their dogs.
A kite flying overhead resembles a predator, and may drive an adult plover off its nest, leaving the tiny eggs exposed to the cold and to predators.
In Southern California, grooming of large expanses of beach disrupts plover habitat, Langham said.
In the long run, he said, some species may adjust to the consequences of climate change: "We just don't know what's going to happen as soon as you start reshaping the elements," he said.