Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

DNA from feathers tells tale of eagle fidelity

07.07.2005


A trail of feathers led a team of Purdue University scientists to confirm that eagles from central Asia are quite possibly the most faithful of birds.


An Eastern imperial eagle chick scolds Todd Katzner, conservation director with the National Aviary, as he collects feathers from the bird’s nest. Katzner is working with geneticists at Purdue University to use DNA from feathers to help determine the conservation status of this rare central Asian eagle. (Photo courtesy of Todd Katzner)



By performing DNA analysis on the feathers left behind at nesting sites, the researchers were able to identify individual Eastern imperial eagles in a nature reserve in Kazakhstan. Their analysis showed that not one adult strayed from its mate - a degree of fidelity highly unusual among birds, the vast majority of which mate with and raise offspring from multiple partners.

Not only is this study the first to confirm monogamy in eagles, more importantly, it also is the first to rely on feathers collected "noninvasively," or without trapping and handling, to provide a source of DNA to determine relationships among individuals and determine various population parameters.


"That we were able to use feathers we collected noninvasively as a source of DNA is the number one thing scientists will be interested in," said Andrew DeWoody, associate professor of genetics and senior author of the study, which was published online Friday (July 1) in the journal Molecular Ecology.

"People have been doing studies like this for several years with mammals, but this is a first for birds."

By developing a protocol for extracting DNA from feathers, the researchers also have added another tool to help conservation biologists study rare and elusive birds of prey.

The researchers used a technique called DNA fingerprinting to help them genetically "tag" individuals in the population without capture, said Jamie Rudnick, the paper’s first author and a graduate student who conducted the study as part of her doctoral thesis.

"Collecting feathers at the nest site helped us determine population parameters we wouldn’t have been able to otherwise," she said.

Those parameters, such as yearly survival rates and ratios of males to females, help conservation biologists monitor populations of rare or endangered species. Noninvasive sampling allows biologists to track changes in populations over time without the risks associated with handling live animals, she said.

"Eastern imperial eagles are hard to catch, and individuals are difficult to tell apart," Rudnick said. "By performing genetic analysis on feathers collected at the site, we were able to track the presence or absence of individual birds over a six-year period."

This kind of monitoring is essential to conserving rare or endangered species, said Todd Katzner, director of conservation and field research at the National Aviary in Pittsburgh and a study co-author.

"You can’t conserve a population unless you know how big it is and whether it’s growing or shrinking," Katzner said. "This approach allows us to monitor wild populations in a way that’s less invasive and more cost-effective than other methods."

Observational studies of imperial eagles suggest these birds, like most large birds of prey, are at least socially monogamous. This means a male-female pair stays together throughout the breeding season and shares responsibility in raising young, DeWoody said.

But just because two individuals act like a pair doesn’t guarantee they’re not having trysts on the sly. In fact, studies over the last decade have shown most broods of socially monogamous birds include offspring from at least two genetic fathers.

"Our study actually stands out as a relatively rare instance in which DNA fingerprinting uncovers genetic monogamy in a bird population," DeWoody said.

Unlike their smaller songbird cousins, most raptors are believed to be truly monogamous, and this study provides the first genetic confirmation of monogamy in at least one species, DeWoody said.

"It’s very likely that other raptor biologists will follow this with similar studies on other species of interest like bald eagles," he said.

This project is one part of a larger research program on the eagles of Naurzumski Gosudarstvennyi Zapovednik (Naurzum State Nature Reserve), a large nature reserve in northern Kazakhstan. This reserve supports an unusual diversity of raptors and is home to no less than 24 different species of hawks, eagles, falcons, owls and harriers.

Also participating in this study were Evgeny A. Bragin of the Naurzum State Nature reserve, Karamendy, Kazakhstan; and O. Eugene Rhodes Jr., of the Purdue Department of Forestry and Natural Resources. The Wildlife Conservation Society provided funding for this project.

Jennifer Cutraro | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Life Sciences:

nachricht Ageless ears? Elderly barn owls do not become hard of hearing
26.09.2017 | Carl von Ossietzky-Universität Oldenburg

nachricht eTRANSAFE – collaborative research project aimed at improving safety in drug development process
26.09.2017 | Fraunhofer-Gesellschaft

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The fastest light-driven current source

Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.

Graphene is up to the job

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Goodbye, login. Hello, heart scan

26.09.2017 | Information Technology

The material that obscures supermassive black holes

26.09.2017 | Physics and Astronomy

Ageless ears? Elderly barn owls do not become hard of hearing

26.09.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>