Eagles on the Mississippi
Can you imagine a world without bald eagles? Magnificent, majestic creatures, soaring over the frozen Mississippi River, scanning the waters for prey. Then that shrill scream rends the air as they dive toward the icy water, talons outstretched, now clutching a wriggling fish as those powerful wings pump, rising into the air, razor sharp talons and beak now digging into dinner as the eagle perches high in a tree. An awesome, fearful sight. And to think that we nearly lost this incredible symbol.
In the early 70s, I remember my Weekly Reader telling me our national symbol was endangered because of chemicals used to rid farms of bugs. A hue and cry from environmentalists and we the people got DDT banned. The chemical itself didn’t kill the birds. It was the effect it had on critters down the food chain. By the time an eagle ate a fish, that fish had such concentrated levels of DDT that, when eagles laid eggs, the shells thinned and cracked, killing the babies inside. No shells, no baby eagles.
Now, in winter, I drive over the Mississippi and see dozens of eagles in the trees where they sit near open water waiting for their next meal. With populations substantially recovered, eagle watching has become a winter draw to the Quad Cities. Endangered species success story, right? Well, maybe.
While banning DDT eliminated one threat to bald eagles, others still exist.
According to Kelly McKay, a wildlife biologist from Hampton, the number of eagles wintering on the river has dropped over the past decade. So where are they?
McKay says this may be due to milder winters up north, but also eagles are wintering farther inland to find more food. Though eagles mostly eat fish, they also eat carrion, such as dead livestock or winter-killed animals. So there are still food sources out there. Problem solved, right? Not quite, because eagles are mostly fish eaters, and McKay has noted the numbers of one specific fish are dropping alarmingly: the gizzard shad. This small, silvery fish often suffers from winter kill in vast numbers due to river icing. In some lock chambers, McKay would see up to 10,000 dead shad. While this may sound bad, eagles would happily feast on these dead fish, and it was a lot easier for them to find food this way.
But in the past two decades, where McKay previously saw huge numbers of dead shad, he is seeing almost none. In some places, numbers have gone from 10,000 to less than a dozen. So what happened to the shad?
McKay’s biggest suspect? Zebra mussels, which clean the water by eating enormous amounts of plankton, the shad’s food source. Once these invasives move in, it’s extremely difficult to get rid of them. But it’s hard to know for sure without research, and McKay says this research would have to happen the same way we learned about the eagles: through citizen scientists. So he is training them through Resource Enhancement and Protection (R.E.A.P.) workshops. He feels with more people trained to observe and record environmental data, we might learn what’s happening to the gizzard shad. And if we can find out, maybe we can figure out how to turn this around.
So the next time you take out a dollar bill, look closely at the eagle on the back, and consider where our country would be without that majestic symbol. Now think about how you, as a citizen, could play a role in helping to work toward securing the future for the bald eagle, who really is more than just a symbol.