Type: Wild
Sources: Complete Adventurer
Masters of the Wild

You can sharpen your sense of smell.
Prerequisite: Wild shape.
Benefit: You can expend one daily of wild shape to gain the scent (see page 314 of the Monster Manual) for 1 hour per Hit Die. While this benefit is in effect, you can detect opponents within 30 feet by sense of smell.
In addition, if you have the Track feat, you can track creatures by scent. You retain this benefit regardless of what form you are in.