Mercury Concentrations in Post-Fledging Wood Storks

Abstract

-Mercury concentrations were measured in blood, down and feather samples collected from 20 postfledging Wood Storks (Mycteria americana) captured in the coastal zone of Georgia to establish a reference level for free-ranging storks utilizing this region and assess if mercury is present in potentially hazardous concentrations. Blood concentrations ranged from 0.04-1.57 gg Hg/g (wet weight) and down and feather concentrations ranged from 1.23-18.05 gg Hg/g (dry weight). Comparisons of observed concentrations with published levels of concern suggest that some free-ranging storks may be at risk of sublethal effects due to mercury contamination. Observed concentrations are generally higher than those reported for Wood Stork nestlings in this region from the same time period, possibly resulting from differences in diet and patterns of down/feather growth and molt. Received 21 March 2001, accepted 5 May 2001.