|Creature-Products||Dead Mallard: Mallard Feather, Entrails, Mallard Meat, Bone Material or Wishbone|
This data is specified at the individual Terrain pages.
It's a male duck. Its female counterpart is the Mallard Hen.
Mallards can easily be caught on horseback. Come at them from behind so that they won't flee in the direction of the water on which they spawned and then simply run after them.
Knarr is another option, you need to be careful not to squash the mallard though, instead carefully going close enough to startle it to fly, then right click it to stat chasing it. (may not work with low quality Knarr.)
Without Horse or Knarr, there is a trick that requires a friend (or an alt) to startle Mallard to fly it towards you, it won't change direction. Works best when both have rowboats.