With the help of a grant from the U.S. Department of the Interior Bureau of Land Management, a team of West Virginia University researchers hopes to gain insight into the demography of golden eagles in California’s Mojave Desert and accurately predict their population trends.
Todd Katzner, a research assistant professor in the wildlife and fisheries resources program in WVU’s Davis College of Agriculture, Natural Resources and Design, and his team will combine field work, genetic monitoring and population modeling to accomplish their goals.
Collecting accurate data will allow the researchers to evaluate genetic uniqueness and monitor turnover rates at nests—vital information for effective conservation and management of a species threatened by increasing demand for renewable energy.
While not listed as endangered, California golden eagles are identified as a species of concern by numerous state and federal agencies including the Department of Forestry and Fire Protection, the Department of Fish and Game, the U.S. Fish and Wildlife Service, and the Bureau of Land Management.
“California’s golden eagles face a variety of threats, but the rapid development of renewable energy such as wind and solar is of particular concern for conservationists,” Katzner said. “Prior studies in California and elsewhere have shown a high mortality rate of golden eagles from collisions with wind energy turbines.”
In an effort to better understand the increasing wind turbine mortality rate among the majestic creatures, Katzner and his colleagues recently used global positioning systems and telemetry units to measure and predict eagle flight behavior.
Almost 10 years ago, Katzner and his collaborators designed the first non-invasive genetic monitoring program for any avian species—an approach that has since been widely adopted by the scientific community.
“Our approach allows us to genetically test feathers collected at nesting sites, and to compare genetic signatures of breeding adults from one year to the next” Katzner said. “Using this method we have been able to estimate key demographic parameters for long-lived eagles with minimal disturbance to the animals.”
The technique resulted in faster data collection, larger sample sizes and greater precision in parameter estimates—all of which will be invaluable to determining genetic uniqueness of the Mojave eagles.
For this study, the researchers’ approach will be two-fold.
Genetic data gathered from the Mojave eagles will be compared to those from Pennsylvania and other regions of the United States to determine gene flow and inbreeding. From there researchers will focus on genomic distinctiveness, proposing to completely sequence the genome (DNA) and transcriptome (RNA) from Mojave eagles.
“Eagle populations in the Mojave area include resident breeders and wintering migrants,” Katzner explained. “Understanding the genetics of these eagles and how they are related to their kin elsewhere in the USA and in the world is critical to building effective conservation management schemes for these populations. For example, we would protect them differently if they are highly genetically distinct than if they are just like eagles anywhere else in the country.”
After determining the genetic distinctiveness, the researchers will then characterize demography measuring survivorship, mortality, durability and territory occupancy by comparing the identities of breeding individuals at nests over time.
“We know eagles tend to remain in a single breeding territory for many years,” Katzner said. “Given that knowledge, it’s reasonable for us to believe mortality is a cause for changes in adults at a territory.”
Although a one-year study won’t completely evaluate a long-lived eagle species, Katzner hopes to create a framework for long-term genetic monitoring of the birds and to provide useful data to allow for both renewable energy development and conservation of a sensitive species.
Joining Katzner on the project are J. Andrew DeWoody, professor of genetics and associate head of the Department of Forestry and Natural Resources at Purdue University, Adam Duerr and Tricia Miller, research biologists with the WVU Research Corp., Philip Turk, assistant professor of statistics in the WVU Eberly College of Arts and Sciences, and Jacqueline Doyle, a postdoctoral scientist at Purdue.
For more information on Katzner’s current and past projects, visit http://katznerlab.com/.
