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Algae feasts on the sun’s rays. A snail grazes on the algae before being eaten by a fish. Satisfied by its meal, the fish swims lazily at the surface where it is snatched up by an eagle who eventually dies and feeds a worm. Nature recycles. Welcome to The Nature of Phenology where we share the cycles and seasons of the outdoors. I’m your host, Hazel Stark, and this episode was written by Joe Horn.
As we creep ever closer to the darkest day of the year—the winter solstice—nights have grown long, days have grown short, and the precious warmth bestowed upon us by the life-giving sun has waned. As this seasonal cold has sunk in, I have watched ice creep over the surface of water bodies, then thicken, and creep further. While this ice cap over our inland waters can certainly mean great fun for us humans who skate and ice fish, it means that certain fish-eating predators must look elsewhere to catch a meal on the go. This couldn’t be truer for the feature of today’s program that has been recently relocating themselves as lakes and ponds freeze: bald eagles.
The eagle population rebound is still relatively new after their unfortunate and completely avoidable population crash due to the widespread usage of the pesticide DDT as reported by Rachel Carson in her world-changing book Silent Spring. Talking to my parents, they never remembered seeing eagles in their home state of Connecticut until the 80’s and even then it was a rare occurrence. And so it was no surprise that they, being the nature nerds they are, loaded me, my brother, and a massive space telescope in the family car to drive over an hour to a small dammed river to watch a convocation of eagles.
After the long drive, we piled out of the car and my parents unloaded and set up the telescope. With its 1980’s burnt orange color, 9” diameter, and imposing shiny steel tripod, this telescope only came out of my parents’ bedroom closet when there was truly a spectacle we had to see. I fondly remember my dad pulling out this telescope to gawk at celestial events as a family. What added to this mystique even more was that we were even allowed to stay up way past our bedtime for these celestial spins. So I knew that we were in for something special that day at the dam.
We wandered down the pathway to a small viewing blind and my parents set up the telescope. I remember hearing the chirps of the bald eagles which I thought sounded more like a gull than the menacing scream so often depicted in patriotic pop culture. And so there we sat for what seemed like forever watching a steady show of five eagles diving for fish, bringing them up to a perch, and swiftly tearing them apart. Better yet, we got a front row seat to the action as zoomed in as one might find in a David Attenborough film—albeit upside down in the viewfinder of the telescope, which was much better used for stargazing.
So why are eagles so fond of dams? As our seasons grow colder and bodies of water freeze, eagles are forced from their summer haunts on lakes, ponds, and large rivers to open water in search of food. The agitation of a surface-drawn dam, or the warm temperatures of a bottom-drawn dam mean that the water downstream is often completely clear of ice which allows the eagles to access their favorite food: fish. But there is a more sinister reality at play. Along with the flow of water, fish that are intent on migrating down our rivers will try to make the leap over or through the dam. Whether simply stunned or killed outright from the poor fish passage of New England’s plethora of antique dams, many of these fish will float up where they are easily observed and snatched by the hungry eagles. While this can be helpful for the eagles, this is just one symptom of a very serious problem that dams pose to our native fish.
So this weekend, you might consider heading over to a local dam to see if there happen to be any eagles hanging around looking for a quick meal. One such dam that has a stellar reputation for pumping out plenty of eagle food is the Milstar Dam in Waterville and Winslow, but many of our state’s large dams will do. Better yet, you could bring a kid along to share the joy of observing these large and charismatic birds. [eagle sound here]
You can find a link to the full transcript of this show as well as references, contact information, and accompanying photos by visiting archives.weru.org. You can also listen to or download our features or subscribe to podcasts. Theme music was by a pileated woodpecker, made available by the US Fish and Wildlife Service. Thanks for listening and please join us next week for another dive into The Nature of Phenology.
Robinson, D.A. and G. Kukla, 1985: Maximum Surface Albedo of Seasonally Snow-Covered Lands in the Northern Hemisphere. J. Climate Appl. Meteor., 24, 402–411, https://doi.org/10.1175/1520-0450(1985)024<0402:MSAOSS>2.0.CO;2