Your body hunches and shrinks as dusky feathers sprout from your skin. Your arms become wings and your toes sharpen into talons.
You take the form of an owl or raven, as chosen when you cast the spell. Even though your Intelligence changes to 2, you retain your normal ability to understand your surroundings (unlike a normal animal). See the polymorph subschool for more details.
As its name suggests, this spell’s most common use is for unobtrusive observation, but it also allows a druid to overcome obstacles that hinder overland travel.
Source: Complete Scoundrel, page 106.