An explanatory series focusing on one of the most complex issues facing California: water sharing. And at its core is the Sacramento-San Joaquin Bay Delta. Stay with kcet.org/baydelta for all the project's stories.
As we mentioned in our piece on the salt marshes of San Francisco Bay, about 95 percent of the Bay's once-abundant salt marshes have been lost. We've built landfills and freeways on them, diked them and filled them to extend our cities and our parking lots, or dredged them out to build marinas. And the result is that one of California's most productive ecosystems has been almost wiped off the face of the earth.
We know better now. We've learned the value of those formerly disdained salt marshes for flood control, for increased water quality, and as habitat for wildlife.
But the damage we've done persists, and thus it's no surprise that one of California's most endangered animals is wholly dependent on those salt marshes: the California Ridgway's rail.
Formerly known as the California clapper rail, the Ridgway's rail isn't just dependent on salt marshes in general: it requires a certain configuration of salt marsh, namely edges -- "ecotones," in the jargon -- between cordgrass and mudflat or slough.
Gray-brown chicken-sized shorebirds with long, downward-curved bills, California Ridgway's rails (Rallus obsoletus obsoletus) use the open mudflats and sloughs, and low stands of pickleweed as a larder, foraging for clams, crabs, mice, lizards, small fish; just about anything they can fit down that downward-curved beak. When they're feeling a little bit too exposed, they head into the adjoining cordgrass to hide out.
That sheltering cordgrass also gives the rails a place to nest, breed, lay eggs, and rear their coal-black young -- which look remarkably like the "susuwatari," or soot sprites, from Miyazaki's films. At extremely high tides -- "rail tides" -- the cordgrass becomes too wet for the rails' liking, and they head up onto higher ground, where birders who pay attention to tide tables will often be waiting with binoculars.
Some of those birders may still be grumbling at the rail's name change, which was only made official in 2014. Generations of Bay Areans, yours truly included, learned the bird as the California clapper rail, Rallis longirostris obsoletus. That was based on century-and-a-half-old assumptions that the West Coast rails were part of an East Coast species. But genetic work completed last year showed that three West Coast rails -- the one in San Francisco Bay, along with the birds formerly known as the Yuma and light-footed clapper rails, should actually be three subspecies of a unique West Coast rail species, which the researchers named for the late ornithologist Robert Ridgway, who first described the California subspecies.
Once fairly widespread in other estuaries along the Northern California coast, the California Ridgway's rail may have had a range extending from Morro Bay to Humboldt Bay. Now, the subspecies is pretty much restricted to San Francisco Bay, which was always its stronghold. About 500 individuals remained in 1991, a perilous low point for the subspecies' population. Numbers have climbed somewhat since then.
That phrase "chicken-sized" pops up in most descriptions of the rail, and 19th Century Bay Areans took that to heart: stories abound of San Francisco restaurants with racks of roasted rails in the window. But the big blow to the rails' numbers came as a result of our changing its habitat.
With 95 percent of the Bay's salt marshes gone by the 1960s, it's no wonder the Ridgway's rail nearly winked out of existence. The rail -- then called the clapper rail -- was listed as Endangered under the U.S. Endangered Species Act in 1970, which probably saved it from oblivion.
The rail's fate isn't secured yet. Despite renewed efforts in the last 30 years to restore the bay's salt marsh habitats, rising sea levels may well undo that hard work and drown out existing salt marshes. Invasive cordgrasses may reshape the edges on which the rail depends.
Nonetheless, restoration efforts on behalf of the salt marsh are helping ensure that habitat fore the rail will continue to exist, which means the Ridgway's rail may still be popping out for your grandchildren and their kids to watch during rail tides. Though who knows what the birds will be called by then?