When the birds leave our yard it becomes quite silent, but we make up for it by visiting our nearby bridge roost, which consists of 100,000 martins from the coastal plain area, including our own. The sound of the birds coming in the roost over water is deafening. Recently we took a sunset boat trip where Amelie and Noah first experienced those 100,000 birds in flight all around them.
Noah knows what martins are, when they are flying overhead he points to the martins and "flaps his wings." Amelie was pointing out all the nice motorists who were obeying the new speed limit, and driving slowly on the bridge to avoid hitting and killing the birds. So now she understands what her mom is doing when I have to leave home to go "save the martins!"