They say that ‘birds of a feather flock together,' which is a more positive trend than ever for the United States’ bald eagle population.
According to the U.S. Fish and Wildlife Service’s (USFWS) 2020 Bald Eagle Population Report, the number of bald eagles has more than quadrupled in the lower 48 states since 2009 — from 72,434 individuals in 2009 to 316,700 in 2020 — with nearly 160,000 residing in the Mississippi Flyway, which includes those protected and thriving throughout TVA’s seven-state region.
Upon receiving protection from a series of laws initiated in 1967 and ultimately by the Endangered Species Act (ESA) resulting from the negative impacts of the insecticide Dichloro-diphenyl-trichloroethane, (DDT), bald eagle numbers have slowly rebounded. Shortly after DDT was banned in 2007, the bald eagle numbers were determined to be stable enough to remove the species from the endangered species list. To further conservation efforts, bald and golden eagles were placed under the Bald and Golden Eagle Protection Act. According to Hill Henry, TVA senior program manager for Natural Resources Policy in Environment and Energy Policy, these efforts led to a spike in eagle numbers.
“This is a remarkable recovery from only 417 breeding pairs reported in 1963,” he says. “The ESA and the DDT ban really initiated the recovery. Compliance with management guidelines outlined by the Bald and Golden Eagle Protection Act, which protects eagles and their nests, have continued the positive trajectory of eagle numbers. TVA’s compliance with the Bald and Golden Eagle Act and the ESA has been important in protecting eagles, as well as other imperiled plants and animals throughout the Valley.”
According to Henry, TVA has played a major role in the restoration and conservation of the bald eagle throughout the Valley, especially with TVA’s efforts in water quality improvement in the Tennessee River where bald eagles forage for food.
“At the time, DDT’s impact on eagles and other birds was unlike anything the biological community had ever seen,” he says. DDT was initially used as the first modern synthetic insecticides in the 1940s to combat malaria and typhus among military and civilian populations. It was later banned when scientists linked it to thinning eggshells among eagles and other birds. “The impacts to eagles were quite dramatic once discovered,” Henry says.
In response to the overall decline in eagle populations, TVA began monitoring eagle numbers and working with other agencies to transport eagles to the Valley from other parts of the U.S. in an effort to enhance their protection and ultimately begin restoring their numbers once again.
In addition, TVA participated in the Hacking Program with Alabama Department of Conservation and Natural Resources, which installed nesting boxes on TVA lands in north Alabama and allowed them to raise eaglets until they were ready to be released into the local environment. Today, TVA assesses potential impacts of TVA’s operations on nesting bald eagles and avoids their nests during the breeding season. TVA also sponsors bald eagle “nest cams” with East Tennessee State University’s Department of Biological Sciences to allow viewers to follow the day-to-day activities of eagles in northeast Tennessee (watch here: Eagle Camera (etsu.edu).
“Because the bald eagle is one of the keystone species residing in the Valley, its rewarding to see their numbers rebound throughout the region due to the elimination of DDT, improving water quality in the Tennessee River and the combined management efforts of TVA and the conservation community,” says Henry. “No doubt many species have benefitted from these conservation efforts; but to see such vast improvement in the numbers of a keystone species like bald eagles, this ecosystem-level response to these conservation efforts is quite remarkable.”
According to Henry, this year’s USFWS eagle population report was a highlight for him and his colleagues. But they also recognize that the rise in numbers means an increase in unexpected avian-related challenges.
“We’ve observed eagles nesting on TVA’s transmission structures before, but never as frequently as in recent years,” he says. “During my first 20 years here at TVA, I can recall two eagle nests on TVA structures. In the last five years, we’ve encountered many more. While this is a testament to their restoration, it presents TVA and the electric utility industry with new challenges concerning the safety of eagles and the reliability of our energy delivery.”
Efforts to meet such a challenge have already begun through TVA’s participation in the Avian Power Line Interaction Committee (APLIC), which seeks to develop and standardize policies and procedures that will help the electric utility industry protect avian resources while also enhancing reliable energy delivery. “TVA has a voice in the development of those standards,” says Henry.
With regulations around eagles and migratory birds changing dramatically, Henry says engaging with APLIC gives TVA the opportunity to collaborate and improve methods for future preservation efforts and regulatory compliance.
“Additionally, TVA does not have standardized procedures for addressing the entire spectrum of avian challenges incurred by the agency,” he says. “Environment & Energy Policy and TVA’s Office of General Counsel is developing an MOU with the US Fish and Wildlife Service to document TVA’s compliance with avian-related laws and regulations. We will also initiate the development of a TVA-wide Avian Management Plan this spring with TVA organizations to standardize our procedures, identify and address our avian challenges, and ensure TVA’s compliance with changing avian-related laws and regulations.”
This effort will provide TVA staff with detailed corrective actions that they can use when encountering avian challenges in their day-to-day work.
“This is especially important as we expect eagle and other avian-related challenges to continue to increase throughout TVA’s power service area,” Henry says.
*Eagle Photo by Steve Letson.