Three images of three different waterfowl flapping their wings. Waterfowl flap their wings for several reasons whilst on or in the water. They may flap them simply to dry off after diving; they may flap them to show aggression or as defensive posturing to make them appear intimidating; or they may flap them impress the ladies during courting rituals.
Top Image: My first sighting of a Hooded Merganser this year. The small female Hoodie, in this instance, wants to get on to a ridge of ice fully occupied by much larger Mallards. She puffs herself up and flaps her wings directly in front of the row of Mallards, then she simply shoves her way in, snapping at the Mallards who quickly make room for her.
A male Common Goldeneye during a courting display.
A female Common Merganser drying off after a dive.