The Salt Pond Puzzle: Restoring South San Francisco Bay

  • A California gull comes in for a landing on the gull-filled flats of the South San Francisco Bay salt ponds

    Michael Kern and the Gardens of Eden
  • A California gull, which eats gull eggs (shown here) as well as those of other species

    Michael Kern and the Gardens of Eden
  • USGS biologists in the California gull colony at Pond A6, part of the South Bay Salt Pond Restoration Project where the gulls are encouraged to nest.

    Judy Irving © Pelican Media
  • Sources: Google Maps/South Bay Salt Pond Restoration Project
  • Caitlin Robinson-Nilsen examines a snowy plover egg at the E Ponds in the South Bay.

    Michael Kern and the Gardens of Eden
  • Snowy plovers are tiny shorebirds, whose offspring can fall prey to larger birds like California gulls.

    Michael Kern and the Gardens of Eden
  • Panorama of Salt Pond A6, taken in 2010 before the area was breached as part of the South Bay Salt Pond Restoration Project. Today, the area has accumulated sediment and looks like a natural mudflat. The image was created by stitching together 12 wide-angle frames taken by a camera at 150 feet, suspended from a kite, and is part of the Hidden Ecologies Project,

    Cris Benton
  • A pair of avocets chase a California gull that had snatched their baby from a nest at Don Edwards S. F. Bay National Wildlife Refuge.

    Ken Phenicie Jr.

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The stuff of floating islands -- of ingenuity and determination -- might make the difference for plovers, too. Whatever amount of pond habitat remains will need to be enhanced. Across the Bay, for instance, is an experimental plot -- "the bird laboratory" -- in pond SF2, nested in the R complex beside the Dumbarton Bridge: 30 giant islands for nesting and high-tide refuge. SF2's archipelago was constructed for $9 million in 2010 as part of the restoration's first phase, and what happens there will inform future projects. "At low tide, a lot of mud flat is exposed," says Strong –– providing forage for shorebirds. "And there are deep areas for dabbling ducks." In 2011, 154 avocet nests and five snowy plover nests were counted on the islands -- a real success. Then again, if you concentrate waterbirds, predators might notice. SF2 is far from the gulls' home range, but for similar projects nearer Alviso, says Ackerman, "all that effort essentially could be devastated if California gulls go in and depredate."

In general, the restoration project is trying to do more with less, and that, too, could buoy the plover. "They have been here for almost a hundred years now," says Robinson-Nilsen, and with little human presence, "this is one pocket where we can do something pretty easily to help them survive." The bird observatory has tried to help the birds by enlisting volunteers to leave footprints -- plovers nest in incongruities -- and sprinkling white shells across dry pond bottoms for camouflage. But they're still searching for effective, low-budget ways to improve plover habitat.

Ultimately, significant acreage will need be to left for snowies if they're to hang on, says Robinson-Nilsen, and those ponds will need to be meticulously managed, drawing down water in late February, while ensuring ditches stay full all summer for wet pecking grounds. The restoration plans to provide nine dedicated plover ponds. SF2 includes one such "nursery," which incubated 13 nests in 2011. But this winter, pond E8a -- where 60 nests were found in 2011 -- was breached and flooded; though it could be a natural fluctuation, 81 fewer nest scrapes were found in the South Bay this year.

The restoration is designed to proceed cautiously, as part of its adaptive management philosophy. Its plan outlines "triggers" for individual species, red flags that would compel the project to pause, reassess -- or halt altogether, even short of 50/50. Snowy plovers would pull their trigger by dipping below the 99 birds counted in 2006 before restoration commenced, or by declining in number for several years. "But we can't guarantee species will use the habitat we create and enhance," says John Bourgeois, the project's executive manager. "Birds do unpredictable things." This year, no plovers were seen on SF2's pricey islands.

The official Bay Area recovery goal is 500 breeding plovers, and 3,000 for the entire coast. Robinson-Nilsen thinks anything more than 250 is a stretch, though, even under the 50/50 scenario. "Where are the other 250 going to go? There's almost no habitat anywhere else. Partially it's that this target did not take into account the restoration -- the fact that their habitat is going to be cut in half in the next 10 years."

We sat in the truck for another hour, keeping the rousted gulls off the levee between A22 and A23. There were just 23 gulls when we arrived this time, and the bird observatory was going to scale back hazing. "One day, they definitely kept me on my toes," Robinson-Nilsen remembered. "I was so glad that this area is closed to the public because I'm sure I looked crazy." Hundreds of the rascals circled and settled behind the Explorer, again and again. An interspecies game of chase ensued. Now, the wind rocked the truck, whistled around its mirrors. "Last night," Robinson-Nilsen told me, "I had a dream that we found two gull nests on this levee." The nightmare jolted her awake. "But that's not true yet. Hopefully, it won't be."

Her premonition hasn't transpired. Twelve thousand of A6's evicted gulls conveniently nested in the adjacent A14 colony last year, while others were absorbed safely elsewhere. And oddly, only 38,000 nested in total. For whatever reason, many apparently didn't attempt to breed.

This year, the breeding gull count is 52,700, a new record. But the gulls didn't even show up at the levee I helped defend. Instead, they tried to seize several of SF2's new islands, which, says Robinson-Nilsen, "is the last thing we wanted." So the bird observatory resumed its patrol by kayak -- a little bit more challenging, especially since Robinson-Nilsen is currently pregnant. Every day for three weeks, she paddled out, blowing her whistle sharply. The birds flew to a neighboring islet. She gave chase, no doubt looking crazy.

Movement, you might say, is the estuary's only surety. After all, the Bay didn't exist until about 10,000 years ago, when the ocean first slid through the Golden Gate after the last ice age. The marshes didn't settle until 3,000 years ago, when the sea level steadied. Before the salt ponds, there were no snowy plovers, fewer waterbirds; before the landfills, and perhaps the Mono land bridge, no California gulls to harass them. Only recently have we begun to influence these tides, let alone become aware we were doing so. Yet now we help decide which species go where, or even which survive.

On the levee last year, I asked Robinson-Nilsen if she ever felt a sense of loss about what was once here, before we filled it in and blocked it out. "It's amazing to think about this landscape before all this development," she replied. "Wetlands stretching as far as the eye could see. But still, there's so much wildlife here -- it's just different wildlife."

Nick Neely is a Bay Area native, or perhaps invasive. After receiving a master's in literature and environment from the University of Nevada, Reno, he interned at HCN in 2010, and now lives (temporarily) in New York City. He sends his sincere apologies to the salt marsh harvest mouse, for devoting all of his words to the birds.

This story was made possible with support from the Kenney Brothers Foundation.

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