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Body symmetry of Forster’s terns (Sterna forsteri) in San Francisco Bay was related to blood and feather mercury concentrations. Body asymmetry can affect a bird’s fitness by reducing flight efficiency, thus increasing energetic costs (especially during migration) and interrupting normal feeding and breeding behaviors.
Herring, G., Eagles-Smith, C.A., and Ackerman, J.T., (2017). “Mercury exposure may influence fluctuating asymmetry in waterbirds.” Environmental Toxicology and Chemistry, 36(60), 1599-1605, doi: 10.1002/etc.3688.
Herring, G., Eagles-Smith, C.A., and Ackerman, J.T. (2016) “Fluctuating asymmetry in waterbirds in relation to mercury exposure.” U. S. Geological Survey Data Release. https://dx.doi.org/10.5066/F7KW5D5Z