Mercury Contamination Similarities Found Between Birds and People
Birds aren't that different from people. We learn from our parents, just like zebra finches learn songs from their fathers. We are active and noisy during the day, like birds, and we can also be territorial. Also like birds, we try to attract mates through colorful displays and beautiful songs. Birds are sensitive to pollution in their environment just like we are: harmful elements such as mercury wreak similar havoc on human and bird biology alike. Because our species share so many attributes, studying birds illustrates the connections between them and us.
Avian researcher and life-long naturalist/bird watcher Claire W. Varian-Ramos has been studying the connections between humans and our feathered friends through the lens of pollution effects, specifically mercury’s affect on bird biology and behavior. After previous studies demonstrated the ability of environmental contaminants such as mercury to result in the birth of more females than males (sex ratio) in wild bird populations, similar findings have been reported for human subjects.
"Mercury is a potent neurotoxin affecting birds and other wildlife worldwide," Varian-Ramos wrote as co-author of a study published last year in Ecological Indicators. "Mercury contamination poses a threat to wildlife in ecosystems worldwide, particularly large, predatory species such as bald eagles (Haliaeetus leucocephalus). Mercury can affect behavior and reproduction in birds, and high levels in the diet can cause mortality."
Now a postdoctoral researcher and instructor at The College of William and Mary in Virginia, Claire’s work continues to focus on human-caused rapid environmental change and its harmful effects on birds. In a recent 2012 article on the effects of mercury on birds at a contaminated river site, published in the Journal of Avian Biology, Claire explained as co-author, "Mercury is a ubiquitous environmental pollutant that can negatively impact physiology and behavior of vertebrates, causing sub-lethal changes in condition and reducing fitness." In this study, her team studied three species at contaminated sites and all three exhibited sex ratios shifted towards females "in the predicted direction of greater production of females, and at a magnitude of 5-15% from that observed at reference sites."
Varian-Ramos has discovered that, like people, birds do not react uniformly to environmental contamination. After replicating circumstances sadly common in the wild—as a member of the Institute for Integrative Bird Behavior Studies—Varian-Ramos' interdisciplinary research team will soon publish the details of their lab study which investigated the variety of negative behavioral, physiological, and developmental effects of continued low-level mercury poisoning of songbirds.
Read more at MONGABAY.COM.
Eagle image via Shutterstock.