eagle

Populations of the American bald eagle — the bold national symbol of the United States — have quadrupled since 2009, according to a new report by the U.S. Fish and Wildlife Service and its partners.

Bald eagles once teetered on the brink of extinction, reaching an all-time low of 417 known nesting pairs in 1963 in the lower 48 states. However, after decades of protection, the banning of the pesticide DDT, and conservation efforts with numerous partners, the bald eagle population has flourished, growing to more than 71,400 nesting pairs.

According to scientists from the Service’s Migratory Bird Program, the bald eagle population climbed to an estimated 316,700 individual bald eagles in the lower 48 states. This indicates the bald eagle population has continued to increase rapidly since our previous survey.

To estimate the bald eagle population in the lower 48 states, Migratory Bird Program pilot biologists and observers from many Service regions, programs and contract observers conducted aerial surveys over a two-year period in 2018 and 2019. The Service flew aerial surveys over high-density eagle nesting areas to generate accurate estimates and count occupied nesting

territories.

To obtain information on the lower density eagle nesting areas, the agency worked with the Cornell Lab of Ornithology to use eBird relative abundance data to acquire information on the areas that were not practical to fly as part of our aerial surveys.

“Working with Cornell to integrate data from our aerial surveys with eBird relative abundance data on bald eagles is one of the most impressive ways the Service has engaged with citizen science programs to date,” stated Service Assistant Director for Migratory Bird Program Jerome Ford. “This critical information was imperative to accurately estimate the bald eagle population in the contiguous United States, and we look forward to working with Cornell in the future.”

“One of our main objectives was to see if population modeling based on the Cornell Lab’s eBird data would enhance the survey work the Service was already doing,” said Viviana Ruiz-Gutierrez, Assistant Director of Cornell Lab’s Center for Avian Population Studies, who supervised the lab’s role in this partnership. “We now have greater confidence in using our results to supplement the Service’s monitoring efforts, and we’re hoping that this will allow the Service to track bald eagle populations over a much wider area in the most cost-effective manner in the future.”

Based on those two major sets of data for this population estimate, the Service next created an integrated population model to expand the estimates of the number of occupied nests across the plot area to estimates of the entire population in the lower 48 states. Information on survival rates, productivity and breeding rates provided the information needed to make this conclusion.

This technical report is the second in a series of reports that have been published on bald and golden eagles. For more information on bald eagle management and additional background, please visit the Eagle Management page.

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