Sep. 18, 2013 — In an article published today in the journal PLOS ONE, researchers at Cornell University's Laboratory of Ornithology report that in some environments, songbirds exhibit inconsistency in their songs which may be caused by non-lethal levels of contaminants that persist in the sediments of the Hudson River region.
The research reported in "The Effect of Polychlorinated Biphenyls on the Song of Two Passerine Species," was funded by New York Sea Grant, a joint program of the State University of New York, Cornell University and the National Oceanic and Atmospheric Administration.
Lead author Dr. Sara DeLeon, working with principal investigator Dr. Timothy J. DeVoogd and co-investigator Dr. Andre A. Dhondt, studied songbirds that nest along the Hudson River valley, a region with legacy levels of PCBs as a result of decades of electronics manufacturing upriver. Polychlorinated biphenyls (PCBs) are synthetic chemical pollutants with demonstrated detrimental toxic and developmental effects on humans and wildlife.
"Dr. DeLeon's work would have brought a smile to the face of Rachel Carson," said William Wise, Interim Director of New York Sea Grant. "This type of dedicated field research can tease out the impact of organic contaminants in the environment on creatures that are known to all of us. Sara and colleagues are drawing the connections between contaminant, animal behavior and, ultimately, a population's health."
Songbirds feed their young PCB-contaminated aquatic insects as their main food source. Some birds continue eating insects throughout life, thus increasing PCB ingestion if they live in contaminated areas. The research team non-lethally investigated total PCB loads, congener specific PCB profiles, and songs of black-capped chickadees (Poecile atricapillus) and song sparrows (Melospiza melodia) along a historical PCB gradient at the Hudson River in New York State.
Key among the team's findings is that song disruption is tied to specific types of PCBs -- there are 209 variations, differentiated by the positioning and number of chlorine atoms. DeLeon tested 41 of these variations to isolate their effects.