MEDFORD/SOMERVILLE, Mass.--When faced with environmental threats like bad weather, predators or oil spills, wild birds secrete a hormone called corticosterone. Traditionally, researchers have analyzed blood samples to detect corticosterone levels in wild birds.
But recently, scientists have shown that corticosterone spikes can also be detected by analyzing bird feathers. A Tufts University study published in the May 11 online edition of "Journal of Avian Biology" confirmed the new technique as a useful way to determine avian stress response not only to sudden natural threats but also to human-caused activities that have a long-term impact on the environment, such as large construction projects or oil spills.
L. Michael Romero, professor of biology in the School of Arts and Sciences at Tufts, says the findings will be useful to conservationists. "There is a fair bit of public interest in whether human activities create stress in wildlife," says Romero, who directed the study that was led by doctoral student Christine R. Lattin. "The idea is that we can determine whether human changes will leave a record of stress in birds' feathers."
Feathers Offer Advantages Over Blood Sampling
For researchers studying stress in birds, feathers present significant advantages over blood sampling. Scientists can obtain feather samples by collecting naturally-molted feathers from the nest without having to handle birds.
Also, blood samples provide only a snapshot of corticosterone in the blood at the moment the blood sample is drawn. Feathers, however, reflect hormone levels during the time it takes feathers to grow, says Lattin.
"This is important in understanding the long-term impacts of stressors on animals, because stress hormones are mostly beneficial in the short term, and only become a problem when they are at high levels for a sustained period of time," Lattin says.
To test the hypothesis t
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