Visitors in the millpond park are surprised by the violence and commotion when ducks mate. It’s truly a spectacle that happens often from mid-spring through at least early August. When a hen is attacked by one drake, other males immediately rush to the scene and most will participate in one way or another. Some will fight with other males for dominance (right) while others are intent upon mating.
I haven’t witnessed a drowning of a hen, but I can see how it happens. Males grab the females by the neck with their bills and hold their heads under water. Most females are strong enough to take a breath once in a while, but if her health is compromised in any way, she might not survive.
Most of these wild splashfests only last a couple of minutes, but I’ve seen females continue to be attacked for up to ten minutes on land or in the water, sometimes both. It seems counterproductive from an evolutionary standpoint, but perhaps the purpose of these encounters is to test the strength of both the males and females. Only the strongest produce offspring.