The Gathering by Kelley Armstrong

Maya was adopted and had accepted that. She knew she looked Native, but didn't know an exact tribe and she had a birthmark on her hip in the shape of a paw print. An old woman in town calls her a "skin-walker" and things start to unravel until Maya realizes the woman was right.

Another great story by Kelley. Towards the end of the book she started to connect it back to the Summoning, reckoning, and awakening series with Project Genesis and the name, Elizabeth Delaney. If you read those books, those would all sound familiar, but you didn't need to read those books to understand this one, but I'll be interested to read the Calling to see how she connects everything.