I've also seen ducks at the seaside (Black sea) in the spring and I was surprised by that. Usually there are a lot of seagulls. Now in the summer the ducks vanished to lakes and other places and just the seagulls rule everything on the sea. And they are quite aggressive (larger gulls are aggressive omnivores that occasionally kill and scavenge smaller birds, ducklings, or injured members of their own or other species during territorial fights or extreme food shortages).