Solving the problems of tracking birds

Just 25 years ago, tracking migratory birds using radio transmitters was a dream to most biologists because the technology was so expensive and batteries were short-lived. Today these problems have been resolved, and the price of transmitters has become almost reasonable.  

And thanks to the Internet, the public need not wait for months or even years for new information to get into print. Many researchers post their findings online, and some even include maps showing the movements of migrating birds.  

For example, in Ohio biologists attached radio transmitters to a mated pair of ospreys in September 2005. As their locations were posted on the Ohio Department of Natural Resources Web site, anyone could follow their progress. Both wintered in Brazil’s Amazon basin, but only the male returned in the spring of 2006. He acquired a new mate, then returned to the Amazon in the fall of 2006. Last spring he returned to central Ohio, reproduced and returned once again to the Amazon last fall. Ohio biologists have not received any signals from his transmitter since October, so either the transmitter failed or the bird is dead. All of this information as well as maps of the birds’ movements have been available on the Ohio DNR Web site (www.dnr.state.oh.us).

In Pennsylvania, Dr. Todd Katzner, Director of Conservation and Field Research at the National Aviary in Pittsburgh, has teamed up with the Pennsylvania Game Commission, Powdermill Avian Research Center (www.westol.com) and the Ministère des Ressources naturelles et de la Faune (www.mrn.gouv.qc.ca/faune/index.jsp) in Quebec to track the movements of golden and bald eagles throughout the east.  

In November 2006, Katzner and his team captured two golden eagles in western Pennsylvania and outfitted them with satellite telemetry devices. These new-generation devices are solar powered and can last up to three years.  

These birds spent last winter in southern West Virginia and Kentucky, then moved to northern Quebec in the spring, presumably to nest. They’re back in West Virginia and Kentucky for the winter, where Katzner suspects they thrive on road-killed deer. Follow the progress of these golden eagles as well as several bald eagles at the National Aviary’s Web site (www.aviary.org).

Finally, news just came in this week on six radio transmitter-equipped peregrine falcons released in West Virginia’s New River Gorge back in July. These birds were part of a group of 24 young falcons released in hopes of reintroducing a wild population of peregrines to the Gorge. They were taken from nests on bridges along the east coast. Biologists moved the young falcons to temporary nests along the rim of the Gorge where they fed them quail as they adapted to their new environment and learned to fly and hunt on their own.

When the birds left the area later in the summer, signals from the transmitters were periodically relayed to a satellite, then bounced back to a receiving station and recorded for tracking and analysis purposes.

One young falcon traveled north to Canada, then south to the Gulf of Mexico, traveling a total of more than 11,060 miles since July. It is now wintering near Mobile, Ala. Another individual spent some time in the Pittsburgh area before heading south and settling in the Tallahassee, Fla., area. Yet another was spotted on a Christmas bird count in downtown Greensboro, N.C.

Three other falcons are now hunting along the Gulf of Mexico and have been tracked more than 100 miles offshore, where, “we think they may be roosting at night on oil rigs or ships,” according to Matt Varner, a wildlife biologist for the National Park Service.

“Sixty percent of peregrines die in their first year, so these falcons have really battled the odds,” Varner said. “Their initial flights are the riskiest, but now that they’re on their winter hunting grounds, they should be good for a while. We hope to get some of these birds back to the gorge.”

To follow the movements of the New River Gorge peregrine falcons, visit www.nps.gov/neri/naturescience/peregrine_2007.htm.

X Send questions and comments to Dr. Scott Shalaway, RD 5, Cameron, WV 26033 or via e-mail my Web site, http://scottshalaway.googlepages.com.