Jason Townsend, a Ph.D. candidate at SUNY College of Environmental Science and Forestry in Syracuse New York and VCE research associate, was awarded Best Presentation by Association of Field Ornithologists at their annual meeting. His presentation was titled, Catharus thrushes as bioindicators of mercury hotpots: from the Catskills to the Caribbean. VCE co-authors on the presentation were Chris Rimmer and Kent McFarland and Charles T. Driscoll from Syracuse University, Center for Environmental Systems Engineering.
Jason’s research documented mercury bioaccumulation in a densely forested watershed of the Catskill Mountains, NY. Mercury is a potent neurotoxin that accumulates in the environment as a result of global atmospheric pollution. While many studies have documented mercury accumulation in aquatic ecosystems, little is known about mercury cycling in strictly terrestrial ecosystems. Jason’s study showed that mercury accumulation in the soil and leaf litter increased with elevation in this watershed. Thrushes of the genus Catharus, which are arrayed along this elevational gradient, also showed increased blood mercury content with increasing elevation. High elevation Bicknell’s Thrushes (C. bick- nelli) and Swainson’s Thrushes (C. ustulatus) showed significantly greater blood mercury levels than did lower elevation congeners, Hermit Thrush (C. guttatus) and Veery (C. fuscescens). This finding could have particularly important health and conservation implications for Bicknell’s Thrush, which is generally restricted to forests above 1000 m in the northeastern United States. Furthermore, blood mercury levels in all species declined with season, indicating that early-season thrushes either carry mercury from their winter grounds or consume a diet higher in mercury during the early part of the breeding season (May –June 15).
An additional analysis of mercury in Bicknell’s Thrushes wintering on Hispaniola showed the highest blood mercury levels of any birds in this study and also wide, site-specific variance, potentially reflecting local pollution patterns.
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