The San Francisco Bay is designated as a site of hemispheric importance to shorebirds and annually supports over one million waterbirds. The San Francisco Bay is highly urbanized but is currently undergoing the largest tidal wetland restoration effort on the West Coast of the United States. These dramatic habitat shifts, high levels of human disturbance, and a highly modified predator community exert significant pressures on locally breeding waterbirds. Despite these pressures, San Francisco Bay supports the largest breeding population of American Avocets and Black-necked Stilts on the Pacific Coast, and over 30% of the Pacific Coast breeding population of Forster’s Terns.
Within the USGS WERC waterbird breeding ecology program, we are studying habitat selection, movements, and factors influencing waterbird nest success and chick growth and survival. We have found that waterbirds rely heavily on salt ponds for breeding and foraging, and this wetland habitat type should continue to be a part of the mosaic of restored wetlands within the Estuary. We have also found that predation on waterbird nests and chicks is high, with California gulls representing a predominant predator within the Estuary. We also have found that mercury contaminantion within the Estuary is high, and may be currently impairing avian reproduction.
USGS Contact For This Project
Ackerman, J.T., C.A. Eagles-Smith, J.Y. Takekawa, S.A. Demers, T.L. Adelsbach, J.D. Bluso, A.K. Miles, N. Warnock, T.H. Suchanek, and S.E. Schwarzbach. 2007. Mercury concentrations and space use of pre-breeding American avocets and black-necked stilts in San Francisco Bay. Science of the Total Environment 384: 452-466.
Ackerman, J.T., C.A. Eagles-Smith, J.Y. Takekawa, J. Bluso-Demers, D. Tsao, and D. Le Fer. 2009. California gull movements in relation to nesting waterbirds and landfills: implications for the South Bay Salt Pond Restoration Project. Administrative Report, U. S. Geological Survey, Western Ecological Research Center, Davis, CA; 64 pp.
Iverson, S.A., J.Y. Takekawa, S. Schwarzbach, C.J. Cardona, N. Warnock, M.A. Bishop, G.A. Schirato, S. Paroulek, J.T. Ackerman, H. Ip, and W.M. Boyce. 2008. Low prevalence of avian influenza virus in shorebirds on the Pacific Coast of North America. Waterbirds 31:602-610.