Studying the Bay’s Birds

In April, the U.S. Fish and Wildlife Service (USFWS) released a report summarizing over five years of studying San Francisco Bay’s waterfowl. This report comes on the heels of several other reports on long-term monitoring of the Bay Area’s waterbird populations, particularly in response to the wetland restoration underway through the South Bay Salt Pond Restoration Project and elsewhere. So, what are we learning about the ducks, grebes, geese, gulls, and many other species that rely on the Estuary, particularly as we work to bring back thousands of acres of historic wetland habitat lost to development?

In late 2018, the U.S. Geological Survey (USGS) produced Trends and Habitat Associations of Waterbirds using the South Bay Salt Pond Restoration Project, based on 13 years of data that analyzed bird abundance in relation to various habitat characteristics, such as salinity, depth, topographic relief, etc. In addition, the San Francisco Bay Bird Observatory (SFBBO) recently completed an assessment of over ten years of monitoring data of waterbird abundance trends in the South Bay restored and unrestored salt ponds. These assessments have found that many guilds using the South Bay salt ponds have doubled or even tripled in abundance since restoration efforts began in the early to mid-2000s. These findings echo the results of the USFWS Fall Midwinter Waterfowl Survey 2013-2018, which assessed waterfowl use of open bays, salt production ponds, managed ponds, sloughs, marshes, inlets, coastal lagoons, and other near-coastal waters throughout all parts of the Bay including Suisun Bay. The Midwinter Waterfowl Survey generally found the highest abundance of waterfowl and coots in the North Bay and South Bay salt ponds (including both active salt production ponds, managed ponds, and restored areas).

Nevertheless, not all waterbird populations are rebounding in these locations. Phalaropes may be declining in abundance within the South Bay Salt Pond Restoration Project area, and as Bay Nature Magazine reported last year, surf scoters have been in decline throughout the Bay for decades. 

The findings of these reports will continue to be evaluated by scientists and resource managers, as the results point to the many ways our great diversity of waterbirds respond to different management actions and restoration strategies. The release of these reports completes or significantly advances the following tasks under Action 6: Maximize habitat benefits of managed wetlands and ponds.

Task 6.1: Produce a yearly report on bird response to specific management measures, and share progress within five years – 100% complete

Task 6.2: Produce report comparing bird use of various habitat types in the Bay and share results – 60% complete