Sunday, April 11, 2021

Bald Eagle Numbers in the Lower 48: Great News

Environmental & Science Education, STEM, Behavior, Biodiversity 

Ed Hessler

Bald Eagle (Haliaeetus leucocephalus) numbers are up across the contiguous United States according to a new estimate reported by Gustave Axelson in All About Birds (March 24, 2021; updated March 26). 

The new number from the USFWS Bald Eagle Population Update report is 316,708, writes Axelson, "is more than quadruple the eagle population reported in the 2009 report. The rising number of Bald Eagles undoubtedly reflects the continuing conservation success story that stretches back to the banning of DDT in 1972."

And it also in some measure represents better survey data, "a major advance by the USFWS in using citizen-science powered supercomputing to generate better estimates for the eagle population."  However, Brian Milsap, the raptor coordinator for the USFWS Division of Migratory Bird Management noted in the press conference that "'the vast majority of this increase really is attributed to Bald Eagle population growth." (my emphasis). Axeslon's report has a great graphic illustrating where the eagles are found across large regions of the United States and a bar graph showing the number of nests with breeding pairs from the low in 1963 to the number in 2020.

The Cornell Lab of Ornithology has developed animations of relative species abundance to show movements throughout the year. Here you may watch how this changes throughout the year for the Bald Eagle.

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