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[whitespace] Clapper Rail
Photograph by George Sakkestad

Feathered Frenzy

The California clapper rail dwindles because of shrinking habitat and a sly fox

By Jim Rendon

Name: Rallus longirostris obsoletus
Status: Endangered
Natural Habitat: San Francisco Bay and coastal wetlands
Last Stand: San Francisco Bay Wildlife Refuge, Palo Alto Baylands
Reason for Demise: Loss of protective marsh, red fox, feral cats

SOMETIMES EVOLUTION can be a bit of a joker. Species that come of evolutionary age in relative isolation have the unfortunate habit of losing the defenses that more streetwise species rely on for survival. They not only become vulnerable to change but also sometimes can seem utterly unprepared for the world around them. The California clapper rail is one of those evolutionary punch lines.

The rust-brown bird, a little smaller than a chicken, is only found in the San Francisco Bay area, an ecosystem that, for tens of thousands of years, kept the bird safe from all manner of predators. The dense marsh that circled the bay before it was filled in for freeways, cul-de-sacs and glassed-in offices covered nearly 200,000 acres. In some areas of the South Bay, nearly a mile of marsh separated grassland from bay. The few predators that were interested in the bird had to traverse acres of bog on their way to a meal.

As a result, the birds don't fly well, covering at best a hundred yards or so in each flight. Lacking webbed feet, they don't swim well either. Like other bay birds, clapper rails lay their eggs on the ground. And they have a terrible habit of standing still when they are in danger. The only thing they have going for them, says Joy Albertson, a biologist with the San Francisco Bay Wildlife Refuge, is that they can run like mad. Unfortunately, their habitat is underwater half the time.

Needless to say, the rails are in bad shape.

During the gold rush, thousands of them were killed a week and shipped to San Francisco restaurants, where they were served up as a delicacy. Since then, the rail's habitat has virtually disappeared. Eighty percent of the bay's wetlands were filled in for development or converted for ponds used to make salt. In the South Bay, only tiny slices of healthy marsh remain, hugging the edges of Cargill's vast complex of salt ponds.

By 1991, there were only about 300 clapper rails left in the world. Those remaining rails were falling fast to predators, mostly feral cats, Norway rats and red fox, all species introduced by humans. Since most of the remaining strips of marsh are linked to levees surrounding the salt ponds, predators have easy access to the birds and their nests.

Officials at the refuge began trapping and destroying fox and cats. And the trappipng has created new hope for the bird. In this decade alone, the rail population has grown from a few hundred to nearly a thousand. Seven hundred rails now make their homes south of the San Mateo Bridge.

But the rails may have a larger problem to worry about. There is simply not enough marsh remaining to support a robust population. With only a few thousand acres of healthy salt marsh left in the South Bay, any significant loss of habitat or birds due to something like an oil or chemical spill could easily doom the species, Albertson says.

Until the South Bay regains more of its traditional marshland, the clapper rail will remain at risk.

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From the November 24-December 1, 1999 issue of Metro, Silicon Valley's Weekly Newspaper.

Copyright © 1999 Metro Publishing Inc. Metroactive is affiliated with the Boulevards Network.

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