When most people think of this iconic bird, they associate them with Alaska not the midwest. The bald eagles of Iowa is a large flock that migrate there in the winter. Not really sure where they come from but I do know they migrate. They leave Iowa in the spring. The eagles young and old take part in a feast of fish that the Mississippi river supplies. They particularly like the locks and dams on the Mississippi. The locks and dams stun the fish temporarily bringing them to the surface of the river. This makes a great buffet for the Baldies. I visited a couple locations while I was searching for this symbol of america. I found two that were pretty well populated with eagles. The first place was at Credit Island Park. See map below.
Credit island is a nice park with picnic tables, swings for the kids, and even an old tank. In the winter it turns into a Bald Eagle resting area as it overlooks the Mississippi river. They use the trees in the park to look over the river for any fish that may come to the surface. You can capture eagles perched in trees, but from this location it's difficult to get any action shots of eagles plucking the fish from the cold waters.
The second place and the better of the two was a place called Lock and Dam 14 Park. See map below. I first arrived just after sunrise and it was -5 degrees fahrenheit(wind chill was much colder). I was a bit hesitant about getting out to explore, but as soon as I pulled into the parking lot, there was an eagle perched in a nearby tree. I grabbed a few clicks and after that the temperature seemed less bothersome.
I walked around this small park and at a certain vantage point I could see about 70-80 bald eagles perched in the trees. They all gathered in this one particular area. It was a cool sight, but to far away to get a good photograph. As the sun got higher in the sky the eagles began to do their fishing. When one would grab a fish it drew the attention of the other eagles and many would chase that eagle to get the fish away. This resulted in some mid air scraps and wonderful photo opportunities. I would say that a 400mm would be the shortest lens to use. If you are capable of renting a lens I would go with a 500mm or 600mm, and that would get you some pretty awesome images.
The winter season in and around the Mississippi and the quad cities are great for Bald Eagle images. I haven't seen another place like it! I will be going back, next winter with a longer lens! The images below are from both Credit Island park and Lock and Dam Park 14. I was using a 70-200mm with a 1.4 extender.