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Levels of Mercury in Feathers of Clapper Rails (Rallus crepitans) over 45 Years in Coastal Salt Marshes of New Hanover County, North Carolina

Fournier, Auriel M.V., Welsh, Kyle James, Polito, Michael, Emslie, Steven D., Brasso, Rebecka
Bulletin of environmental contamination and toxicology 2016 v.97 no.4 pp. 469-473
Rallus, bioavailability, birds, carbon, coasts, diet, feathers, foraging, habitats, mercury, nitrogen, salt marshes, stable isotopes, North Carolina
We sampled clapper rail (Rallus crepitans) feathers from museum specimens collected between 1965 and 2010 to investigate changes in mercury (Hg) availability in coastal marshes of New Hanover County, North Carolina. Stable isotope analysis (δ¹³C and δ¹⁵N) was conducted to control for dietary shifts that may have influenced Hg exposure. Hg concentrations ranged from 0.96 to 9.22 μg/g (ppm), but showed no significant trend over time; diet (δ¹⁵N) or foraging habitat (δ¹³C) also provided little to no explanatory power to the variation in Hg concentrations among clapper rails. Our findings suggest the bioavailability of Hg to clapper rails in coastal North Carolina salt marshes has remained consistent over time, despite the global trend of increasing mercury in many other bird species, providing an excellent baseline for any future assessment of Hg availability to salt marsh birds in coastal North Carolina.