Everybody knows about the California clapper rail, the charismatic (though elusive) endangered bird of San Francisco Bay marshes. The San Pablo Baylands shelter almost half its known population. But here the clapper shares the wetland with its smaller, quieter, and still more elusive cousin, the California black rail, Laterallus jamaicensis coturniculus.
The black rail is sparrow sized—five to six inches long—and dark slate in color, with faint white bars on its sides, a chestnut nape, and a back with prominent white spots. You need good timing and good luck to glimpse it. Researchers estimating its numbers don’t even try to look; they listen, broadcasting its call—Grr kkick-kic-kic—and counting the answers they get.
The black rail spends most of its life in mature stands of pickleweed or alkali bulrush, where spaces under the canopy allow movement and nesting. The best sites are near creeks or sloughs with slightly higher vegetated ground nearby to provide escape in very high tides: refuge both from the water below and from predators—herons, egrets, harriers—in the air above. The rail itself eats aquatic invertebrates, land insects, and possibly seeds.
While there are outlying colonies on the ocean coast and even in the Sierra foothills, most of the birds are found around San Pablo Bay and in Suisun Marsh. The highest concentrations are in the Petaluma Marsh Wildlife Area and at several points along the Napa River, including White Slough in Vallejo. Though not as near the brink as the clapper rail, the black rail is a California Threatened Species and a federal Species of Management Concern. Its full recovery depends on expanding the number of marshes that are large, remote, and fully tidal: just the kind of living spaces that the San Pablo Baylands can now provide.