Monitoring Kentucky’s Bald Eagles
The bald eagle is one of the most successful and well-known species recoveries in North America. Despite widespread declines in the mid-1900’s, Kentucky’s nesting bald eagle population is growing at a rapid pace, with 123 occupied nesting territories documented during the spring of 2013. The national Midwinter Eagle Survey has demonstrated that Kentucky’s winter eagle population is also doing well. These standardized surveys, which occur each January, have resulted in counts of 250-400 eagles throughout the state in recent years.
Although winter and nest monitoring projects have been documenting an increase in bald eagle populations in recent years, biologists still see many questions left unanswered. Do Kentucky’s bald eagles migrate during cold winters? What happens to young bald eagles that hatch in Kentucky nests? Do Kentucky eagles survive well over the long term? What threats do bald eagles still face?
Kentucky’s eagle tracking project was started in 2010 in hopes to answer many of these questions that other eagle monitoring projects do not address.
Kentucky Eagle Tracking Project Background
Kentucky’s bald eagle tracking project began in May 2010, when the Kentucky Department of Fish and Wildlife Resources (KDFWR) partnered with The Center for Conservation Biology (CCB) to attach satellite transmitters to nestling bald eagles at Ballard Wildlife Management Area (WMA) in Ballard County, KY. The project was later expanded to include the capture of immature and adult eagles by rocket-net at Ballard WMA and Doug-Travis WMA in Carlisle County. Each year 2010-2015, KDFWR deployed at least one satellite transmitter on a bald eagle in order to learn more about the movements of these birds.
The eagles wear a 70g solar-powered GPS-PTT satellite transmitter. The transmitter weighs about the same as 20 pennies. This is less than 2% of an eagle’s body weight. The transmitter is attached externally, like a backpack with a harness made of special Teflon ribbon. The transmitters do not interfere with flying, hunting, mating or nesting and allow biologists to safely and easily follow the movements of these birds. The transmitter powers on once every hour and a tiny GPS unit inside it takes a location for the bird which is accurate to about 50 ft. Then, every three days the transmitter turns on and sends all of these locations to satellites, which in turn bounce the information back to earth. Biologists and the public can then view the locations and learn about the birds.
Click each bird’s name in the menu near the top of the page to read about each bird’s story. Please visit the following link to view interactive maps for the tracked bald eagles: http://www.seaturtle.org/tracking/?project_id=506
Solar panels recharge the transmitter’s battery, and in general provide about three years of tracking data from each bird. The transmitters will provide important information on the following aspects of bald eagle ecology, which will help to inform conservation decisions for bald eagles in the future:
- Home Range
- Habitat Use
- Threats (Use of High-Risk Areas)
KDFWR is no longer putting transmitters on bald eagles due to limited staff time and funding. However, updates on birds that are still transmitting will be posted to this site and a detailed analysis on this project will be released soon.