Iowa had nesting eagles everywhere when the first settlers arrived, but there were no nesting eagles in the state for most of the 1900s. Habitat loss and later the use of DDT drove them to near extinction in all but the more remote areas of Alaska and Canada. Their recovery in much of their historic range is one of our top conservation success stories.
The bald eagle was not a unanimous choice as our national bird. Benjamin Franklin preferred the wild turkey and felt the eagle was what he called a "sharper" - one who made a living by dishonest means. Eagles are opportunistic feeders. They prefer fish, but are not averse to eating carrion (dead meat). They will feed on whatever they can find if fish aren't readily available. That includes everything from waterfowl, turtles and even frogs! They frequently steal food from each other and from smaller raptors like the osprey. The bald eagle was selected in spite of objections due to its power and majestic appearance.
Eagles can live 20 years in the wild, and even longer in captivity. They mate for life, but will take a new mate if one is lost. It takes them a long time to reach sexual maturity for a bird. Most eagles don't mate until they're at least four years old, the first year they'll actually display the characteristic white head and tail.
Eagles typically lay two eggs each year and begin their nesting cycle in late winter when there's still danger of the eggs freezing if left unattended at the nest for more than a few minutes. Both parents help to incubate the eggs so that each has a chance to feed. In good times when food is plentiful and bad storms are few both young often survive to at least fledging. Young eagles may die after leaving the nest due to accidents like hitting power lines, car accidents, or even starvation. Hunting is a learned skill, and like people, eagles don't learn at the same rate.
Even though egg shell thinning DDT was banned years ago, eagles are still threatened by human activity. One of the chief causes of eagle mortality today is lead poisoning. Lead poisoning of eagles is one of the reasons that non-toxic shot is now required to hunt waterfowl. A continued source of lead comes from feeding on dead game birds and animals that were not retrieved by hunters. They also pick up lead fragments from gut piles of field dressed deer and from the hides and boned out carcasses of deer that are left out in the field. It takes only a tiny amount of lead to make an eagle sick. Sick birds may not be able to breed even if they live, or may become so weak that they can no longer hunt and die of starvation.
Bald eagles have been nesting in ever increasing numbers in Iowa. Thirty years ago, I was speaking to groups saying things like, "Lacking the proper habitat, we can't expect to ever see nesting eagles in Grundy County." But there are at least four nests in the county this year. One is north of Grundy Center. A second is south of the County Collection Center (old landfill). The third is about a mile and the fourth is a mile west of Morrison. All have had activity this winter by pairs adding more nest material to them. If you suspect an eagle nest elsewhere, let me know please.