Published on the Web 12/3/2007.
Mercury concentrations in blood and feathers of prebreeding forster's terns in relation to space use of san francisco bay, california, usa, habitats†
Article first published online: 9 DEC 2009
Copyright © 2008 SETAC
Environmental Toxicology and Chemistry
Volume 27, Issue 4, pages 897–908, April 2008
How to Cite
Ackerman, J. T., Eagles-Smith, C. A., Takekawa, J. Y., Bluso, J. D. and Adelsbach, T. L. (2008), Mercury concentrations in blood and feathers of prebreeding forster's terns in relation to space use of san francisco bay, california, usa, habitats. Environmental Toxicology and Chemistry, 27: 897–908. doi: 10.1897/07-230.1
- Issue published online: 9 DEC 2009
- Article first published online: 9 DEC 2009
- Manuscript Accepted: 17 OCT 2007
- Manuscript Received: 28 MAR 2007
- San Francisco Bay
We examined mercury concentrations and space use of prebreeding Forster's terns (Sterna forsteri) in San Francisco Bay, California, USA, to assess factors influencing mercury levels in piscivorous birds. In 2005 and 2006, we collected blood and feathers from 122 Forster's terns and radio-marked and tracked 72 terns to determine locations of dietary mercury uptake. Capture site and capture date were the most important factors explaining variation in blood mercury concentrations (geometric mean ± standard error: 1.09 ± 0.89 μg/g wet wt), followed by sex and year. Accordingly, radiotelemetry data revealed that Forster's terns generally remained near their site of capture and foraged in nearby salt ponds, managed and tidal marshes, and tidal flats. In contrast, capture site and capture date were not important factors explaining variation in feather mercury concentrations, probably because feathers were grown on their wintering grounds several months prior to our sampling. Instead, sex and year were the most important factors explaining mercury concentrations in breast feathers (9.57 ± 8.23 μg/g fresh wt), and sex was the most important factor for head feathers (6.94 ± 7.04 μg/g fresh wt). Overall, 13 and 22% of prebreeding Forster's terns were estimated to be at high risk for deleterious effects due to mercury concentrations in blood (>3.0 μg/g wet wt) and feathers (>20.0 μg/g fresh wt), respectively. Breeding terns are likely to be even more at risk because blood mercury concentrations more than tripled during the 45-d prebreeding time period. These data illustrate the importance of space use and tissue type in interpreting mercury concentrations in birds.