... or ducky pr*n.
The mallards are pairing up. We shouldn't have been surprised, but we were; we assumed that they would wait until the spring, but when I looked it up, I found that mates are chosen in the fall, and courtship continues all winter.
We watched several couples engaging in the mating rituals this Friday on Reifel Island. It starts with the male preening and making odd sounds, grunting and whistling to attract her attention. Then he faces her, beak to beak, and starts to bob his head straight up and down. After a bit, she joins in, and they sit there in the water, looking like one of those string-operated antique toys. (I had to laugh, but they were oblivious, fortunately.)
When they tire of this game, the male starts pecking the female gently on the top of her head or the back of her neck ...
... until she lies flat in the water. Then he mounts her, holding on by the feathers on her head. Maybe he's being helpful, keeping her head above water; maybe he's just preventing her escape.
When it's all over, the male swims away, and his mate takes a bath.
These couples are more or less monogamous (he's not quite as faithful as she is), and will stay together all winter until she lays her eggs in the spring. Then he will abandon her to hide away and go through his spring molt. She will not molt until her duckings are ready to move out on their own.