Wild Birds Along Contaminated River Have Altered Songs
Photo credit: Rain0975
Wild birds have..."simpler, shorter, lower-pitched songs."
Wild birds that live along the mercury contaminated South River just outside of Waynesboro, Virginia were found to sing "simpler, shorter, lower-pitched songs." Wild birds rely on their voices for mating and protecting their territory. The researchers included Kelly Hallinger, a freshman at the time with College of William and Mary in Williamsburg and her professor, and ecologist, Dan Cristol.
Species whose voices she captured included the house wren, Carolina wren, and the song sparrow. Hallinger recorded hours of singing and compared the results to non-contaminated birds. "Sonograms showed the uncontaminated birds reached high notes of around eight kilohertz, while the mercury-fed birds' highest notes topped out at around six kilohertz."
Not the first time
This is not the first time we've heard about mercury contamination in wildlife, or that mercury disrupts their natural behavior. Many animals can become exposed due to "mine tailings, industrial effluent, agricultural drainwater, impoundments, and atmospheric deposition from electric power generation" (Wolfe). It has also been found that exposure to metals such mercury cause "significant physiological and biochemical responses" without overt signs of toxicity (Scheuhammer). So birds can be seriously, even fatally, contaminated even though they show no outward signs of it. They can experience a decrease in egg production, an increase in death rates, and young birds are typically more sensitive to these effects (Scheuhammer).
Wild Birds' Songs, Feather Colors Changed By Mercury Contamination (2014, August 28). In National Geographic. Retrieved 13:48, August 30, 2014, from http://news.nationalgeographic.com/news/2014/08/140828-bird-song-mercury-language-brain-science-winged-warning/.
Wolfe, M. F., Schwarzbach, S. and Sulaiman, R. A. (1998), Effects of mercury on wildlife: A comprehensive review. Environmental Toxicology and Chemistry, 17: 146–160. doi: 10.1002/etc.5620170203
Scheuhammer, A. M. (1987, Febuary 4) The Chronic toxicity of aluminium, cadmium, mercury, and lead in birds: A review. DOI: 10.1016/0269-7491(87)90173-4
Other links to check out: Dan Cristol's Webpage: http://wmpeople.wm.edu/site/page/dacris