Even Low-level PCBs can Change Bird Songs
Fascinating research out of Cornell that has some troubling implications given the pervasiveness of some pollutants in the environment.
Researcher Sara DeLeon, working on her Ph.D. at Cornell University, looked at blood samples of Song Sparrows and Black-capped Chickadees and discovered that presence of PCB (polychlorinated biphenyls) disrupts how these species sing their songs. The birds come in contact with the toxins when they ingest contaminated insects, and the study found that the chemicals appear to mimic hormones in the bird’s brains and interfere with the parts of the brain that affect song and song structure.
The species in question were excellent indicators of the effects of this type of pollution. Both Black-capped Chickadees and Song Sparrows feed primarily on insects while feeding nestlings, not only consuming the toxins themselves but passing them to their young. Both species are mostly non-migratory and common in the study area, a stretch of the Hudson River in upstate New York. Between 1947 and the late 70s – when PCBs were finally banned – General Electric manufacturing plants in the area dumped more than 1 million pounds of PCBs directly into the Hudson River. The Hudson River drainage contains high PCB levels even now, nearly 40 years later.
How did DeLeon determine the structural differences in the songs of these birds? At the Guardian, Grrlscientist explains:
http://blog.aba.org/2013/09/even-low-level-pcbs-can-change-bird-songs.html?utm_source=rss&utm_medium=rss&utm_campaign=even-low-level-pcbs-can-change-bird-songs
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