Impacts on Bald Eagles Portend Climate Change Effects in the Land-Sea Interface

More than 30 years of information reveal factors that could help predict whether nests will succeed.

By the editors of Park Science magazine

About this article

This article was originally published in the "Research Roundup" section of Park Science magazine, Volume 39, Number 1, Winter 2024-25 (January 15, 2025).

Bald Eagle in flight carrying a fish in Glacier Bay National Park and Preserve.

Image credit: NPS / K. Smith

Bald eagles on the U.S. Pacific Coast nest and breed on land but get most of their food from the ocean. Studying them can help us understand how extreme events, like the northeast Pacific marine heatwave of 2014–2016, affects interconnected marine and terrestrial ecosystems.

Researchers looked at more than 30 years of information on bald eagle nesting in Alaskan coastal areas. They wanted to see how nest success relates to weather conditions, food availability, and the 2014–2016 marine heatwave. They published their results in the November 2024 issue of Ecosphere.

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The researchers found that prey hotspots, like where bears feed and leave many salmon carcasses, were a good predictor of nest success. So were warmer, drier springs with plenty of salmon. Nest success in areas with fewer salmon declined once the marine heatwave began. These results foreshadow the potential impacts of a warmer climate on bald eagles and other such terrestrial species.

Schmidt and others. 2024. The effects of spatiotemporal variation in marine resources on the occupancy dynamics of a terrestrial avian predator. Ecosphere 15: e70078.