Scientists are turning to baby eagles in Michigan to gauge the health of the environment. Eagles, being top predators, give us clues about water quality since they are closely tied to lakes and rivers.
Eagle biologists Bill Bowerman and Mike Wierda are on a mission. They navigate through Michigan following GPS coordinates to find bald eagle nests. “You certainly see parts of Michigan you wouldn’t normally explore,” Wierda shares, highlighting the adventure.
In the back seat, there’s a large blue cooler full of vials containing baby eagle blood, preserved at a frigid minus 70 degrees. Bowerman and Wierda, having grown up near lakes in different parts of Michigan, now work at universities out of state. They reunite each spring and summer for their research.
However, funding for monitoring eagle and waterbird health has been cut in recent years. This time around, they volunteer to continue their work.
Collecting eagle blood is crucial because it serves as a concentration point for environmental contaminants like DDT, PCBs, and mercury. As eagles have distinct territories, the data over time helps scientists monitor the ecosystem’s health.
“The trends in those populations are vital for assessing aquatic health,” Bowerman explains. They rely on aerial surveys to guide them to eagle nests.
Once they reach the designated area, they split up to search for the nest. Bowerman moves effortlessly through the brush, looking for signs of the eagles, like “whitewash” and clusters of twigs.
After some searching, they locate the nest, which is impressively large—about five to eight feet across. Wierda prepares to climb the 70-foot tree to collect the eaglets.
“When I get to the nest, the babies are adorable. They hold their wings up and make cute noises,” Wierda says.
As Wierda begins his ascent, two adult eagles circle above, but they seem quieter than usual. After about an hour, he reaches the nest—only to find it empty. This is unexpected.
“What a bummer. We saw clear signs of eaglets,” Wierda remarks, puzzled.
It’s unclear what happened. Just two weeks earlier, aerial surveys had captured images of two eaglets. The team wonders if a storm brought them down or if they could have starved. They search the area but find nothing.
Bowerman, who started this project in 1961 and has been studying it actively since 1984, shares, “This is unusual.” They suspect a mix of factors is at play, potentially contributing to recent eagle losses.
To navigate funding issues, Bowerman and Wierda formed a nonprofit called Wings Over Water Research Institute, dedicated to ongoing eagle research. Their previous work included groundbreaking studies, such as one that tested eagle eggs for PFAS, published in Environmental Pollution.
The data collected throughout these endeavors is more than just numbers. It helps paint a picture of the health of eagles and, by extension, the environment they inhabit. These insights are essential for understanding ecosystem dynamics and the ongoing fight to protect wildlife.
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