Over and Under the Snow by Kate Messner

This one always reminds me of Owl Moon -- what with the story revolving around the father-daughter duo going through the snowy forest, keeping an eye out for animals -- but the actual content is quite different so both are entirely valuable in their own right. Smoothly written, it's an excellent introduction to the subnivean zone -- that layer between snow and ground, which is an entire world in its own right -- full of hibernating animals and also those hunkering down with the larders they gathered earlier in the year and munching their way through the winter. A few top dwelling animals -- deer and foxes, etc. -- make an appearance as well. 

There's a nice glossary at the back where it expands further on each animal mentioned, too. 

A great selection for natural history.