What do you roll to sleep in a hidden spot?

Scenario: a character is alone in the forest, and needs to sleep. Of course, they don’t want to get killed in their sleep, so they try to sleep in a hidden spot, like inside the treetops, heavily obscured by branches and leaves from all sides.

Question is, what do they roll for, if at all, since monsters are all but guaranteed to pass by during the night? Do they roll Stealth (assume the most obscured position), or Survival (find the best sleeping spot & camouflage it)?