The success story of bald eagles in Iowa

The sight of a majestic Bald Eagle perched high in a tree or soaring low over the river is common this time of year in Louisa County. As bodies of water freeze over in Canada and the northern states, Bald Eagles migrate south to join our resident Bald Eagles. They congregate around open water where they can find food. It's common to see multiple birds all in one area as they share the resources. But it hasn't always been this way.

Bald Eagles are native to North America and not found on any other continent in the world making them the perfect national symbol for the United States. Unfortunately, Bald Eagles were hunted as vermin because they occasionally preyed or scavenged on livestock.

As settlers moved across the country, timber habitat was drastically reduced. In the 1940s, pesticides such as DDT and DDE entered the food chain. Runoff introduced these pesticides into the water which in turn affected the aquatic insects and moved into the fish and waterfowl.

The concentration of any toxin increases as it moves up the food chain. For Bald Eagles, the toxins in the fish made the shells of their eggs so thin they broke. DDT and DDE also affected the reproduction of many other birds whose prey includes fish or insects or birds that eat insects.

Pesticides plus hunting and habitat loss meant that the Bald Eagle population dropped to near extinction. In the 1960s there were, on average, less than 4,000 Bald Eagles left in the contiguous United States.

The return of these majestic birds was only possible through the banning of DDT in 1972 and the protections provided through the Endangered Species act in 1978. Programs were created for the conservation of Bald Eagles and preservation of their habitat and nests. Iowa didn't have a nesting pair of Bald Eagles again until 1977.

Each year, during nesting time, a Bald Eagle Midwinter Survey is conducted by the Iowa Department of Natural Resources to evaluate the population in Iowa. As of 2019, Iowa had 431 active Bald Eagle territories with a 66% success rate of the 262 nests surveyed. A total of 2,924 Bald Eagles were counted which is just under two per river mile!

Now is a perfect time to watch Bald Eagles along the rivers of Louisa County. You may see adult pairs carrying sticks in their talons, adding to the bulk of their already huge nest. Or you may see adult Bald Eagles already sitting in their nest, defending their territory. Get outside, keep your eyes open, and enjoy!