D&Dtools1

This spell allows you to adopt the nature and some of the abilities of a particular animal.
Upon casting the spell, you can choose any animal whose Hit Dice are equal to or less than your caster level.
You retain your own form, but you gain the natural and extraordinary senses of the creature you choose, including blindsense, blindsight, darkvision, low-light vision, and scent, as applicable.
You can also choose to replace either or both of your Listen and Spot check modifiers with those of the animal chosen.
For example, a 3rd-level druid casting this spell might choose to adopt the nature of a wolverine to gain low-light vision, scent, and Listen and Spot check modifiers of +6.
Alternatively, she could select the eagle and gain low-light vision, Listen +2, and Spot +14.
If the druid's Listen check modifier were better than +2, she could retain her own Listen check modifier while gaining the eagle's Spot check modifier.