(Reuters) - Tropical birds, from kingfishers to wrens to warblers, are showing signs of mercury contamination as artisanal and small-scale gold mining operations reach deeper into jungles, new research finds.

 

Birds living within 7 km (4 miles) of such gold mining activity were found to have mercury concentrations over four times higher than those living at other sites across the tropics of Central and South America, according to the study published Tuesday in the journal Ecotoxicology.