From Pathfinder Howl of the Wild, which isn't enabled.

Sharpened Senses

FEAT 13

Activity free action

Frequency once per round

Your senses have become so sharp that you notice changes subconsciously. You Seek. If you use one of your senses from Natural Senses, you gain a +2 circumstance bonus to the check.

Pathfinder Howl of the WildORC