A lookout in the rigging of the Walrus.
Lookouts are people in charge of keeping an eye out for things. Ship’s lookouts are in charge of keeping watch for other ships, land, and various dangers. They are usually stationed in the tops or elsewhere in the rigging, and often equipped with a spyglass to aid them in their efforts.
On land, lookouts are often stationed in high places such as hills, so as to have as wide a view as possible.