These are some of the books and stickers the kids and I are learning
The Nature Connection is absolutely the best book for learning about nature journaling that I have ever seen. It covers every aspect needed from weather to stars and from plants to living creatures. It covers the simple materials needed, page set-up, and the how-to on gathering the information for your journal. It would be a great addition to any home library, for any age group, just for its general outdoor information alone.
We also have the usual bird, wild flower, tree and butterfly identification books to refer to when we get back inside and begin to write about and illustrate the things we have seen. The kids love looking at the pictures in them even when we've not been out.