The Ever-after Bird — Ann Rinaldi

Now that her father is dead, CeCe McGill is left to wonder why he risked his life for the ragged slaves who came to their door in the dead of night. When her uncle, an ornithologist, insists she accompany him to Georgia on an expedition in search of the rare scarlet ibis, CeCe is surprised to learn there's a second reason for their journey: Along the way, Uncle Alex secretly points slaves north in the direction of the Underground Railroad.
    
Set against the backdrop of the tumultuous pre-Civil War South, The Ever-After Bird is the story of a young woman's education about the horrors of slavery and the realization about the kind of person she wants to become.