Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Isotopes from feathers reveal bird migration

06.11.2003


Using naturally occurring patterns of stable-isotopes created by weather and plants, Jason Duxbury of the University of Alberta and his colleagues are tracking the migration routes of birds of prey. Their work on the summer origins of migrating and wintering Peregrine Falcons and Burrowing Owls has shed new light on what has previously been the secret, non-breeding half of the birds’ lives.



By analyzing stable isotopes of hydrogen, carbon, and nitrogen in bird feathers, Duxbury has been able to trace Burrowing Owls wintering grounds in southern Texas and central Mexico, as well as migrating Peregrine Falcons caught on the gulf coast of Texas, back to their breeding grounds in Canada.

The principle behind the work is simple: birds are what they eat. And what birds eat while growing feathers on the breeding grounds contains isotopes of hydrogen, carbon, and nitrogen. These vary in predictable patterns across North America.


Duxbury will be presenting a paper on his work on Wednesday, November 5, at the annual meeting of the Geological Society of America in Seattle, WA. Scientists there are exploring the evolving interface between isotope geochemistry and ecology.

Hydrogen and its heavier version, the isotope deuterium, are both naturally found in molecules of rain water. But as the cycle of evaporation and precipitation repeats across North America and over mountainous regions, the heavier deuterium isotopes get left behind. That creates well-mapped hydrogen/deuterium trends across the continent, Duxbury explains.

"There is a well known gradient of depleting deuterium/hydrogen ratios from the Gulf of Mexico and the Atlantic Ocean across the eastern part of North America," said Duxbury. As you get near mountains there is also a noticeable elevation effect that reflects how changes in elevation also cause precipitation cycles.

The hydrogen isotope signature of animals is essentially the isotope signature found in the water and food they eat. Furthermore, the isotope signature found at the bottom of the food chains can be passed up to the top of food chains. The result is that isotopic signatures in the feathers of the top predators reflect the area where the food was consumed while the feathers were grown.

Carbon isotopes, also found in feathers, vary with latitude due to different growing conditions for plants across the continent. Even nitrogen isotopes can help track birds, though nitrogen isotopes variations are not found in predictable patterns. The application of nitrogen-rich fertilizers in agricultural areas can also alter nitrogen isotope ratios, Duxbury explains.

To collect the feathers for analysis, Duxbury and his colleagues rely on other researchers across North America. "Since 1995 I’ve had other researchers who were banding birds gather feathers all across North America," Duxbury said.

In order to get a local isotope baseline for a bird population the researchers first gather feathers from nestlings at their nest sites. Then they gather feathers from birds on migration or on their wintering grounds to trace them back to the isotope baseline based on the nestlings.

In the case of Burrowing Owls, the stable isotope technique has traced unbanded owls wintering in central Mexico back to Canadian breeding populations, said Duxbury. Subsequent analyses have also revealed that Burrowing Owls disperse more widely between breeding seasons than previously thought. That discovery, in turn, can be applied to population models used in the conservation of Burrowing Owls.

This relatively new technique will not replace banding, says Duxbury, since it cannot trace a bird to an exact location. However, the recovery of a banded bird is very rare event, and so it takes decades to accumulate data. Stable-isotope analysis is providing similar dispersal and migration data, but at a far greater rate. In essence, every bird that is captured for a feather sample is equivalent to a band recovery, Duxbury says.

"Essentially, it’s not as good as getting a band return, which gives you A to B," says Duxbury. "You can’t say exactly where a bird’s origin was, but you can narrow it down to a region. For instance, with an isotope signature we can get it back to southern Alberta, whereas a band can get it to an exact nest location."

Satellite telemetry is by far the most accurate method of tracking birds. However, it comes with a hefty price. In addition, technology has not developed satellite transmitters small enough for Burrowing Owls, says Duxbury.

Ann Cairns | EurekAlert!
Further information:
http://gsa.confex.com/gsa/2003AM/finalprogram/abstract_66548.htm
http://www.geosociety.org

More articles from Earth Sciences:

nachricht New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>