the bay by the city
San Francisco evokes an image that is all its own. The city and the surrounding landscape, that includes lovely places like Napa Valley as well as powerful economic engines like the Oakland waterfront and Silicon Valley, is a wonderful expression of how nature can fit within a human-dominated environment. But deep in the bowels of this wonderful place is an unfamiliar feature, a spectacle really, witnessed only by the most determined.
The industrial beating heart of the bay area surrounds south San Francisco Bay, where over a million shorebirds winter or stage each year. Starting just below the Oakland bridge going south along the bayfront to San Jose and the Silicon Valley than north again to the SF Airport you’ll find factories, shipping container docks, vast areas of storage buildings and facilities that include some of the most important tech businesses in the world. Hidden by all are long sections of waterfront with old salt ponds, tidal marsh, mud flats and vast areas of shallow water. Here shorebirds follow the age old rhythm — out with the ebbing tide , in with the flooding tide — while they search for food and places to roost.
The southern bay has long been known for its extraordinary stopover and wintering populations of waterfowl and shorebirds and it has been the focus of superior conservation efforts for years. The bay draws shorebirds in the fall and spring, who seek to replenish lost reserves before continuing to Mexico and other South American countries to winter or to the Arctic to breed, respectively. In the so called “teeth of winter” – which is mostly a succession of very similar days of 50-60 degree F highs and 40-50 degree nights, tens of thousands of western sandpipers, dunlin, marbled godwits, willets, short-billed dowitchers, least sandpipers, long billed curlews, surf birds and others, settle into thier daily routine for about 5 months. In their yearly cycle it’s the most time they will spend in one place
We are beginning a new shorebird project in San Francisco Bay aimed at trying to understand the status of red knots in the bay. Others are working on red knots on the west coast: Roberto Carmona with the Autonomous University of Baja California Sur, Joe Buchanon of Washington Fish and Wildlife and Jim Johnson of US Fish and Wildlife Service in Alaska. But none have focused on the relatively unknown but small population of knots on San Francisco Bay.
The west coast species of red knot Calidris canutus rosalaari, may actually be in worse shape than the east coast subspecies, C.c. rufa. Rufa is declining quickly, mainly because of the collapse of the Delaware Bay stopover and the inability of fisheries agencies to recover the horseshoe crab, but the status of rosalaari is still uncertain. It may have always been low in number or it too may be in decline. The lack of data may mean we will never know.
Tonque-in-check we called our first organized effort an “expedition” to San Francisco Bay,, but in truth it presents unique risks. The southern bay especially below the industrial docks of Oakland and Alameda, is essentially a channel flanked by wide shallows on each side. That why the ducks and shorebirds are there. At low tide these shallows will be around 1-2 feet deep but high tide adds 7 feet of water. The current can be swift and the winds of the bay are strong and variable depending on the season, the tide, the location on the bay and the time. The bay itself is infamous in the sailing world for it strong, gusty and regional winds. These winds are so honored by sailors that the 2013 America’s cup will be held in the bay this year. But these volatile wind conditions, mixed with the shallow waters of the southern bay, can combine to make very hazarding boating.
Two weeks ago we braved the waters of the southern bay, and thankfully it was a lake. Our goal was to find concentrations of red knots, especially roosts, where we could ultimately trap birds to begin our project. We hope to flag knots with uniquely inscribed leg flags, as we do in Delaware Bay, and to attach geolocators, small devices that tracks their movements for a year. We had difficulty reaching the SF bayshore because much of the shoreline is gated from public use, either to protect private property or sensitive areas. Our bigger problem was the extraordinary difficulty of moving from one place to another over land. Most moves requires a ride onto one of the seemingly continously jammed highways like the 101 on the east side or 880 on the west. Also the tidal flats were extensive and at low tide, birds stand far from the land’,s edge and hard to identify. We had to do our survey by boat and we secured the use of a 12 ft Zodiac with a 15 hp outboard.
On our first trip, we went to the west of the bay in the Bair Island section near Foster City. Fortunately, the wind was virtually still and the tide rising. Although we saw only 50 knots, they were among thousands of shorebirds and waterfowl. For a pair of seasoned wildlife biologists like Mandy and I, the sight was awe inspiring. Shorebirds, like the long-billed curlew and western sandpiper, waterfowl like the canvasback and bufflehead, flocks that cover the sky when flushed from the fertile shallow water and ever moving inter-tidal flats. It’s a site only rarely seen in our country but only one more aspect of the beauty of this bay.