Clinton’s skyline tent showcases one of America’s greatest wildlife success stories, the winter migration of bald eagles. This national group of winged acrobats performs daily along the riverfront with their main stage at Lock & Dam 13.
These sky dancers perform aerial acrobatics and claw cartwheels as they fly along the Mississippi River shoreline. Their appearances emphasize the social interaction between eagles in flight which can be courtship, family ties or aggression. Two eagles will chase each other relentlessly when one suddenly grabs upside down and grabs the talons or prey being held by the other. The entangled eagles spin down seemingly uncontrollably, but with the grace of experienced aeronauts, let go of their talons and resume their pursuit game.
Ice conditions along the Mississippi River determine the concentration areas of eagles. Fish is a primary food source, but river ice hinders most fishing opportunities. Eagles then concentrate at the locks and dams where rapid currents flowing over the dam not only keep the tail waters open but also stun and kill the fish, resulting in an all-you-can-eat floating sushi buffet. Eagles also patrol open waters where ducks and geese are common. A slow moving or injured bird will be their next meal.
Eagles are opportunistic eaters, eating road-killed critters, mortally wounded but unrecovered deer, and deer gut piles discarded in the field. Locally, researchers from the U.S. Fish and Wildlife Service collected 58 dead bald eagles and necropsies documented that more than a third had clinical lead poisoning. X-rays of eagles showed tiny lead ammunition fragments were present in their digestive systems.
X-rays were also taken of piles of deer gut and showed that small lead ammunition fragments were embedded in the discarded deer tissue that eagles often preyed upon. A piece of lead smaller than a grain of rice will kill a bald eagle if swallowed. Hunters are encouraged to use unleaded ammunition, such as copper, which is commercially available for shotguns, muzzleloaders, and rifles.
The number of local eagles varies daily and can range from a few individuals to several hundred during river icing. In January 2014, more than 1,000 bald eagles were counted from the observation deck at Lock & Dam 13. Viewing opportunities are usually better in the early morning, but currently hundreds of bald eagles can be seen during the day due to the frozen river channel.
There is a live streaming internet webcam near the nest of our local internationally renowned trio of bald eagles. The webcam provides an interesting glimpse into the daily life of this bald eagle family. Armchair eagle viewers from more than 70 countries follow our eagle trio consisting of two fathers and a mother. The stewards of the Upper Mississippi River Refuge, Army Corps of Engineers and US Fish & Wildlife Service provide the webcams on the Stewards website www.stewardsumrr.org.
We are fortunate to have the Mississippi River at our doorstep. Take the time to visit the riverfront to view our great river and the aerial minuets of the sky dancers.
Ed Britton is a Wildlife Refuge Manager at the Upper Mississippi River National Wildlife & Fish Refuge and a volunteer at Bickelhaupt Arboretum.