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 that corticosterone levels in birds' feathers correspond to levels in birds' tissues, the researchers collected feathers from captive European starlings and compared the feather cortisone levels of starlings with and without experimentally-elevated cortisone (via a small capsule implant)They also collected blood samples from each bird three times during the experiment: before implantation and three and five days after implantation.
The researchers analyzed the feathers in two ways. They divided one batch into subgroups that differentiated three stages of growth—before, during and after implantation.
In the second part of the study, the scientists wanted to determine if feathers from the same bird would have similar corticosterone levels. To do this, they selected two feathers from the same bird.
An analysis of the feathers yielded several findings. The nine starlings implanted with corticosterone had significantly higher levels of the hormone in their feathers during the study period than the other birds. Also, the scientists found no difference in corticosterone levels between feathers taken from the same bird, indicating a consistency in feathers grown at the same time.
Romero and Lattin are collaborating with other researchers to see if this technique can be applied to preserved bird specimens at the Smithsonian Institute in Washington, D.C. Feathers may be a way to determine whether birds that lived in the wild decades ago lived in stressful environments.
"This opens up the possibility to use museum specimens to look at how changes in the environment may have affected the birds," says Romero.
Elevated Corticosterone is Related to Deformities in Feathers
In previous experiments, the scientists found that feathers from birds implanted with corticosterone in had lighter, weaker feathers. Lattin says that the results suggest that elevated corticosterone levels could impact birds' health.
The research was funded by a grant from the National Science Foundation.
Christine R. Lattin, J. Michael Reed, David W. DesRochers and L. Michael Romero
Article first published online: 11 MAY 2011 | DOI: 10.1111/j.1600-048X.2010.05310.x
Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville, and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university's schools is widely encouraged.
Alex Reid | EurekAlert!
How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH
A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology