Maybe a Fox by Kathi Appelt

Sylvie is one year older than her sister Jules. Their mother died a number of years before but they live pretty happily with their father on a big piece of wooded land in Vermont. One day there is a accident and Sylvie is killed.  As Jules and her father cope with another crushing loss in their family, a baby fox is born in the woods near their house.  The fox is connected with Sylvie and Jules somehow, and ends up having an important role to play in Jule's life.

Kathi Appelt is an amazing writer.  She portrays Jules' grief in aching terms and the way that Jules tries to deal with her grief is very believable for a character her age. Like Ghost,(see below), this is getting a lot of critical attention, but I actually liked Ghost better.  I felt like Appelt stuck in a couple too many social issues.  Not only is Jules dealing with the death of her sister, and the earlier death of her mother, but her best friend's brother is dealing with grief because of his friend who died while they were both serving in Afghanistan.  This brother of the friend also has a spirit animal, which is a giant mountain cat that is thought to be extinct.  If they had left out the friend's brother, the giant cat, and Afghanistan I think I would have liked the whole story better.  Still the writing is pretty amazing, so for that reason I can see why it has received some good reviews. (272 p.)