This is so utterly cool.
Every night, just at sunset (and not a minute before) the sound of cackling starts, and many flocks of geese begin hovering overhead. It seems that they are coming from the Missouri River, and heading north over to the Mississippi. They circle and even seem somewhat confused about where they are going. It must be that there are 2 rivers here, so close together. Eventually though, they all go north to the Mississippi.