This past weekend I traveled to the Conowingo Dam at the Susquehanna River along the PA/MD border to see the Bald Eagles who spend the winter here.
The Conowingo Dam is one of the largest non-federal hydroelectric facilities in the US, and when it is generating electricity fish and water are sucked into the dam through large turbines. The presence of these fish attracts large numbers of Great Blue Herons, Gulls, and Bald Eagles.
I was afraid I was too late to see the Eagles because they nest very early (Feb 20 – April 30 in PA), and they leave their wintering locations in early February to begin building their nests. But I was thrilled to count 18 Bald Eagles perched on the rocks and in the trees above the river.
I am reminded that there was a time not too long ago when the presence of even one Eagle along this river was a big deal because the Bald Eagle population crashed due to the bioaccumulation of DDT in their systems. According to the US Fish and Wildlife Service:
DDT and its residues washed into nearby waterways, where aquatic plants and fish absorbed it. Bald eagles, in turn, were poisoned with DDT when they ate the contaminated fish. The chemical interfered with the ability of the birds to produce strong eggshells. As a result, their eggs had shells so thin that they often broke during incubation or otherwise failed to hatch. DDT also affected other species such as peregrine falcons and brown pelicans.
Bald Eagles were placed on the Endangered Species list in 1967, and the road back has been very slow.
The presence of the Eagles now is also a sign of river health. If the river was polluted the aquatic vegetation would not thrive, the fish would not have a food source, and therefore the Eagles would have nothing to eat.
I learned this lesson very well while I was in grad school and spent much of my time working with Clay Sutton, a New Jersey biologist who has spent the last 20 years monitoring river and watershed health on several long-term studies.
Several times a week, I would meet with Clay Sutton and his partner James Dowdell and we would travel to dedicated points to count the number of birds on the water at each site, and thus determine the health of these waterways.
In 1983 only 3 Bald Eagle nests remained in Pennsylvania. Last year over 200 nests were located in this state.
In 1973 New Jersey had only one nesting pair in the state. Last year NJ recorded over 100 nests in the state.
Bald Eagles mate for life and build large nests at the top of trees which they add to every year. Some of these nests have weighed in at over 1500 pounds!
Although it is unlikely that you would have a Bald Eagle nest in your wildlife garden (unless you lived along a river, lake, or estuary), we can all help to ensure the continued recovery of this magnificent bird by eliminating the use of chemical fertilizers, pesticides, and herbicides in our gardens.
These toxic chemicals run off our properties every time it rains, and are washed into our streams and rivers, polluting this water and causing algae blooms, eutrification, and a dead zone in the Gulf of Mexico that is larger than the state of New Jersey.
It is quite easy to manage your wildlife garden without the use of any of these chemicals, as Ellen Sousa has done a terrific job of describing. Our responsibility as gardeners extends far beyond our own garden gates!
Please enjoy this lovely poem by my friend David Bourne, The Eagle (dedicated to his father-in-law Bert on the day of his passing)
And this great post about Bald Eagle recovery efforts in Wisconsin by our new frequent commenter Wisconsin Wildman.
Have you seen nesting Bald Eagles near your wildlife garden?
Carole Sevilla Brown lives in Philadelphia, PA, and she travels the country speaking about Ecosystem Gardening for Wildlife. Check out her new free online course Ecosystem Gardening Essentials, 15 free lessons delivered to your inbox every week.
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