COLUMN: Nesting bald eagles

Michele Olson
Jones County Naturalist

     Who builds a car sized nest of large sticks in the tallest trees? If you guessed the bald eagle, you are correct.

     Nesting bald eagles in Iowa have increased over the past 30 years. If you are over the age of 40 maybe you remember when seeing an eagle in Iowa was a rare occurrence and finding an eagle nest almost unheard of. Now we almost take it for granted that eagles once again soar freely in our sky.

     In Iowa, the bald eagle has made a remarkable comeback for a bird once on the Federal Endangered Species List. Over the past 40 years Iowa’s nesting bald eagle numbers have gone from just a few recorded nests to over 427 confirmed nesting territories with many others unreported and yet to be discovered. You might even be lucky enough to discover one in your own neighborhood!

     Winter is the perfect time to get out and explore the area where you live in the hopes of spotting an eagle nest, also known as an aerie. Made up of large sticks, eagle nests are hard to miss in Iowa’s winter landscape.   Ranging from 5 to 9 feet across and weighing as much as 2 tons, they really stand out!

     Since eagles like to nest near water, they tend to build their nests near rivers, ponds, lakes, streams, and farm waterways. They prefer towering conifer trees, but will build in large cottonwood, oak, and maple trees, usually choosing the tallest tree in the area. This again makes spotting a nest relatively easy since prime nesting habitat in Iowa is fairly limited due to habitat loss, land practices, and rural and urban construction.

     Nesting pairs have a typical territory of 1-2 square miles and will keep other pairs away from their immediate nesting site. They can be observed adding sticks to their nest any time of the year but are especially busy during the winter months preceding the laying of eggs in February and March. That means right now eagles will be close to their nest sites and actively preparing their nests.

     It is important to realize that nesting eagles are protected by law and they and their nests should not be disturbed. Since eagles have only “one shot” to raise their small family of 1-3 eaglets each year, it is vitally important that onlookers keep their distance. Do not approach an eagle nest or disturb the eagles in any way. It is best to observe an eagle nest from a distance with binoculars or a spotting scope.

     Once eggs are laid, incubation takes roughly 35 days. Incubation is mostly done by the female, but the male will pitch in to give the female a break. During incubation, one parent is always on the nest, not only to keep the eggs warm but to protect them from possible predators.

     Newly hatched eaglets can be observed in nests from late April through May. Eaglets are covered with a soft grayish-white down and during cold snaps must be kept warm by their parents. Adult eagles feed their young by shredding pieces of meat from their prey (raccoons, rabbits, fish, squirrels, etc.) with their beaks and offering the pieces to their young. Young eaglets grow rapidly and by three weeks old will be up to a foot tall. By six weeks they are nearly as large as their parents. Young eagles will be ready to take their first flight between 10 and 13 weeks after hatching, which in Iowa is usually sometime in June.

     Watching an eagle nest can be a wonderful family activity. What better way to learn about our national bird and the wildlife that is in our own backyard.

     For more information on bald eagles in Iowa or to report an eagle nest site visit the Iowa Department of Natural Resources website at Another great learning opportunity for all is the Decorah eagle cam which can be viewed at



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