Salton Sea, Calif. – As the Salton Sea’s waterline continue to recede, California’s largest lake is losing some of its iconic bird species, including pelicans and cormorants. The report released today, which aggregates several sources of bird monitoring data, shows how dramatic ecological change at the Salton Sea is forcing some birds out, resulting in fewer overall species of birds taking advantage of habitat.
One of the fastest disappearing species appears to the be the American White Pelican which, according to surveys, has declined from a high of 20,000 birds in 2008 to fewer than 100 now, according to aerial surveys conducted by the California Department of Fish and Wildlife. Audubon’s own surveys shows a similar drop-off on recent years. This decline is largely the result of the Sea’s increased salinity, which is killing off the tilapia upon which the birds feed.
“For a community that once held annual Pelican Days Birding Festivals, the decline of these great birds is certainly disheartening,” said Andrea Jones, Audubon California’s director of bird conservation, and principle author of the new report. “At its peak, the Salton Sea hosted a broad diversity of birds, and any habitat restoration that takes place here should serve that diversity.”
The Salton Sea is one of the most important places for birds in North America, and the larger region is home to about a million people. As part of the Colorado River Delta, the sea filled and dried for thousands of years prior to its current, 35-mile-long incarnation. The 350-square-mile sea has partially replaced wetland habitat lost to agricultural and urban conversion in the Colorado River Delta, California’s coast, and the San Joaquin Valley. For more than a century, the sea has served as a major nesting, wintering, and stopover site for millions of birds of nearly 400 species.
Since 2003, when Colorado River water that filled the Salton Sea in the form of agricultural runoff began to be diverted elsewhere, the state of California has been slow to complete promised restoration and dust control projects. This became ever more urgent at the end of 2017, when water to partially compensate for the loss was cut off, accelerating the falling sea level and increasing the danger of air pollution and habitat loss.
Recent months have brought hope for the Salton Sea. California for the first time has committed substantial funding, about $280 million, for habitat restoration and dust mitigation. While several restoration projects are identified in the state’s 10-year restoration plan, those projects are far behind schedule.
Beyond the pelicans, the new report notes that the numerous Eared Grebe and Double-crested Cormorant are also declining rapidly. Declines have occurred as recently as within the past couple of years. For example, Audubon’s Christmas Bird Count data show an average decline of 63% per year for the past few years for Eared Grebes (once occurring at the Sea in the millions and now at most in the thousands). Double-crested Cormorants, which once had a breeding colony of more than 5,000 nesting pairs on an island within the Sea, have all but disappeared.
But the report also notes significant increases, in the past two years, for shorebirds, such as the Western Sandpiper, and waterfowl, such as the Ruddy Duck. The report notes that these species are taking advantage of large numbers of insects being produced as the receding waterline exposes wet shoreline.
While some species are taking advantage of the current food resources, Audubon has documented an overall decline in diversity, with a 10% decline in species diversity in just the past two years. However, as the shoreline stabilizes in coming years, the Sea’s wet edges dry up, and the Salton Sea becomes more saline, fewer hospitable habitat conditions will persist. The Sea saw a potential preview of that this past January when more than 7,000 Ruddy Ducks died from avian cholera, a contagious disease that affects waterfowl in crowded and stressed conditions.
“Some birds will diminish and other birds will prosper – but the overall number of birds at the Sea is shrinking,” added Jones. “It is my hope that ten years from now, people can visit the Salton Sea and watch large formations of these magnificent birds flying along the shoreline and dropping down onto the water to feed on the fish below its surface.”
About Audubon California
Audubon California is building a better future for California by bringing people together to appreciate, enjoy and protect our spectacular outdoor treasures. With more than 350,000 members and supporters in California and an affiliated 48 local Audubon chapters, Audubon California is a field program of the National Audubon Society. More information is available at ca.audubon.org.