Gulls are often spotted flying around near the Ocean. They are big white birds that drop feathers when you kill them, which are mostly used to make arrows. It’s easiest to kill gulls after they land but they’re almost impossible to melee. Your best bet is to use wooden arrows to get your first couple of feathers.
Gulls will flee whenever you get anywhere near them and sneaking doesn’t seem to help. They also won’t spawn in mid-ocean, so if you see a gull, you know land is near.