San Francisco Bay Restoration: Conversion Of Salt Evaporation Ponds To Tidal Marsh

The purchase of 16,500 acres of salt evaporation ponds from Cargill Salt by the California Department of Fish and Game and the U.S. Fish and Wildlife Service, with added contributions from several philanthropic organizations, was finalized in early 2003. The acquisition is seen as a major milestone in the effort to restore tidal wetlands that used to be a significant part San Francisco Bay's ecosystem.

Having photographed on Cargill's salt ponds and on the largest tract of undisturbed wetlands remaining in San Francisco Bay -- Palo Alto Baylands Nature Preserve -- I thought it would be interesting to do a photo essay featuring images of wildlife utilizing both of these natural and man-made habitats.

The top photo is symbolic of the effort to convert salt ponds to tidal action marsh. The right side shows a former salt pond undergoing experimental restoration at Cargill Salt, while the left side shows an active salt pond -- what the restored pond used to look like. The sharp contrast in appearance and application of these adjacent features prompted me to select a theme of "similarities and differences" for the photo essay.

Stilts resting in salt pond

Similar

The shallow waters of both habitats are havens for feeding and resting shorebirds such as Black-necked Stilts and American Avocets.

Click on images to enlarge

Stilts at Baylands

Caspian Tern nesting colony on island in salt pond

Different

There is a sharp contrast in nesting styles between Caspian Tern and Marsh Wren.

Caspian Terns nest in a large colony and lay eggs in shallow depressions on an exposed island in a salt evaporation pond.

Marsh Wren uses marsh vegetation to weave an elaborate nest hidden in the middle of a flowering mustard plant.

Marsh Wren building nest at Palo Alto Baylands

Snowy Plover at edge of salt evaporation pond

Similar

Both habitats support endangered or threatened species. Snowy Plovers have adapted to nesting on earthen levees forming salt ponds, and are often seen feeding on brine flies at the edge of ponds.

A handful of Black Rails have been seen at Palo Alto Baylands during the highest winter tides when they are forced to make a dash toward shoreline brush to escape rising water.

Black Rail at Baylands

Pair of Clapper Rails stretching near salt ponds

Different

At most locations Clapper Rails are hard to spot, and even harder to photograph. With the photo on the left, taken near salt ponds, it took two birds with outstretched wings, their reflections, and long shadows to barely fill the frame.

Palo Alto Baylands is the one exception. During the highest winter tides Clapper Rails can be seen on higher ground just a few feet away from the boardwalk, providing exceptional photo opportunity.

Clapper Rail at Baylands

Stilt nesting in creek bed adjacent to salt ponds

Similar

Black-necked Stilts are common nesters in both habitats. Around salt ponds Stilts nest on levees, islands, and creek beds. The year the photo on the left was taken late rains raised the water level in the creek, forcing Stilts and Avocets to work at a frantic pace to reinforce their nests to keep eggs dry.

Palo Alto Baylands offers the best viewing of nesting sites since birds are used to foot traffic and tend to build nests very close to the walking trail that starts at the Visitor Center.

Stilts courtship ritual at Baylands

Forster's Tern hovers above salt pond

Different

The fishing methods of the Forster's Tern and the Black Skimmer are quite different. The Tern spots fish from the air, briefly hovers, then dives head first to grab fish with its beak.

The Black Skimmer flies low over water with the tip of its lower mandible beneath the surface, trailing a wake. When a fish is detected by touch its beak would snap shut to secure it.

Black Skimmer skims Charleston Slough

From 1999 to 2002 I was granted special access by Cargill Salt to photograph wildlife utilizing salt evaporation ponds that ring San Francisco Bay from Redwood City to Hayward. During this period, and for several years prior to it, I also photographed at Palo Alto Baylands Nature Preserve and Charleston Slough. My photography around these varied habitats has resulted in a file of over 3,200 photographs of local and migratory birds, which are available for publication and as fine art prints. The file also includes year-by-year documentation of a salt pond conversion to tidal flow marsh, showing growth of marsh vegetation and development of feeder channel.

See the Birds Stock List for a listing of available bird species. You can also read more about wildlife utilizing salt ponds in this article.

If you would like see additional images please email me and I'll be happy to upload images onto a special viewing platform for your private review.