Birds of a feather

With large, hooked beaks, sharp talons, and a wingspan of up to 7.5 feet, golden eagles are powerful and formidable birds of prey.

For biologists who study birds of prey, trapping and tagging them are often the most time-consuming and dangerous part of studying these incredible animals. In addition, golden eagles often make their nests in tall trees or on cliffs along waterways.

“It can take weeks to catch a single bird and, although rare, an eagle can be injured during trapping operations,” said biologist Todd Katzner, a 2003 Arizona State University School of Life Sciences alumnus who studies both golden and Eastern imperial eagles. “As a consequence, it is really beneficial to find ways to study eagles without ever trapping them.”

Unfortunately, it was the only option for scientists who were tracking bird populations at the time.

But one day, while conducting research on the ecology of birds of prey in Kazakhstan, Katzner had an epiphany. Looking around the ground, he realized there were Eastern imperial eagle feathers scattered everywhere.

“I started thinking that since we were already collecting tissues from the birds, there had to be something we could do with these feathers,” said Katzner, who was a doctoral student at the time. “So, I started talking to some geneticists, and we realized there was a critical question we could answer by using these samples: What is the death rate of these birds?”

By analyzing the DNA in the feathers from around a nest, Katzner realized he could track where every individual in an eagle population lived without ever having to directly interact with the birds.

Since eagles typically stay with one mate in one nest until they die, analyzing the feathers over a period of time can tell researchers whether the birds in a specific area are thriving or dying. It also tells them what parts of a habitat cannot be disturbed without causing eagles serious harm.

Katzner said no one had been able to accurately estimate eagle populations before the creation of this tracking method. He happily credits the School of Life Sciences and its faculty for their contributions to his success.

“I had a really positive experience at ASU,” Katzner said. “People challenged me — asked me hard questions. And I think, at the time, it seemed painful. But in the long run, it was the best thing those people could have done for me.”

After holding several post-doctoral positions, his dream job became available at the U.S. Geological Survey.

Today, much of Katzner’s job centers on keeping North American golden eagles safe from a serious threat — the development of wind energy. Eagles that fly below certain altitudes are at great risk of being killed by wind turbines. His job is to determine whether it’s safe to build the turbines in certain habitats, by finding areas where eagles fly high enough to avoid the blades. Katzner does this by using his feather tracking method.

Using the research and tracking skills he developed at ASU, Katzner said his efforts to protect the country’s golden eagle population have already been successful, while also allowing the U.S. to safely gather renewable wind-energy.

“I’m thrilled with what I’ve been able to accomplish,” Katzner said. “This type of work is really what I’d hoped graduate school would allow me to do, and I feel fortunate that it has all worked out so well for me.”

Todd Katzner holds what he believes to be the first adult Eastern imperial eagle ever caught on breeding grounds. Katzner began working with imperial eagles as a PhD student at ASU.