I can't seem to find where the duration of Supernatural abilities is listed. In particular I'm trying to figure out how long a Bogeyman's Striking Fear lasts.
However long the Fear effect it was chained into last.
If someone was shaken for one round, he is now Afraid for one round.
Presumably he usually achieves this by attacking a creature Shaken from his Aura of Fear, which lasts as long as they're in the aura.
It should be mentioned in the ability, reading the Bogeyman's one, it has two halves:
"If a bogeyman confirms a critical hit or a sneak attack with one of its claws on a target currently suffering a fear effect, that effect automatically becomes one step more severe (shaken creatures become frightened, frightened creatures become panicked, and panicked creatures cower in fear). A DC 25 Will save negates this increase." - this changes the step of the fear effect, not its duration, so duration is until the old fear effect ends.
"In addition, a critical hit from the bogeyman's claw forces any target that has successfully saved against the creature's fear aura to make another Will save against its effects, even if 24 hours have not yet passed. This is a fear effect. The DC is Charisma-based."
This is based off of the aura, which states it lasts "as long as it is in the aura."