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Flying Comeback

High above the Bay, beneath its many bridges, an enigmatic, dark-eyed flier is quietly making a comeback. Peregrine falcons, which dive at speeds of up to 200 mph to catch ducks, shorebirds and big city pigeons, have just been removed from the federal endangered species list.

Their removal can largely be attributed to the ban on DDT that began in 1972, as well as extensive captive breeding efforts. DDE, a breakdown product of DDT which the peregrines ingested from contaminated prey, was thinning their eggshells, causing reproductive failure. In 1970, biologists checked over 100 nest sites throughout California and found just two pairs breeding successfully, says Doug Bell, peregrine expert with the San Francisco Bay Bird Observatory. But by the early 1990s, the Bay Bridge boasted two resident breeding pairs, and peregrines were wintering on most of the other bridges and even at the Bay Bridge toll plaza's radio towers.

This past spring, says Bell, peregrines attempted to nest on the Richmond, Antioch, and Bay Bridges, a sea cliff near Muir Beach, and even an office complex at Redwood Shores. "It's likely that five to seven pairs of peregrines now call the Estuary their home," he says.

Because young peregrines are often hit by cars and even drown when they first try to leave their urban lofts, the Santa Cruz Predatory Bird Research Group has been removing the young from the bridges in the spring and releasing them elsewhere around the state.

Could there ever be too much of a good thing when it comes to something as magnificent as a peregrine? They definitely have an impact on concentrations of shorebirds as well as nesting terns, admits Bell. "But the key is to provide enough habitat for the prey - in this case, to maintain a diverse estuarine system that allows the intricate balance between predator and prey to play out. Peregrines are not new to the Bay Area - they undoubtedly witnessed the coming of the first Spanish explorers. Now, thanks to anenlightened public, the peregrine has a second chance to reestablish its rightful place in the Bay Area's ecosystem." And for anyone still worried about their prey, Bell adds, "They eat far more pigeons and doves than ducks."

Contact: Doug Bell (408)946-6548

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