Exploring Creation with Zoology 1 by Jeannie Fulbright (2005, Hardcover, Student Edition)

I was really excited when Apologia came out with some science books for elementary grades. My son had started with Apologia's General Science when in 7th grade, and we loved the conversational, chatty style. One can quickly forget that he's reading a text book and almost think he's found a novel! In FLYING CREATURES, like other Apologia texts, the focus features one area in depth rather than a shallow overlook of a broad spectrum of subjects, allowing the student to feel that he has a real understanding of something rather than year after year "learning" the same thing over and over again in hopes that at some point he will retain some of it! For example, one whole lesson is about the feathers of a bird, rather than just a paragraph. By the end, the child really understands how God made feathers to work so beautifully together for warmth, nesting, and flight. (Did you know that white feathers are warmer than dark feathers?! And we always thought the ptarmagan was white only to blend with the Arctic snow!)
When my daughter, not an avid reader, gets enthusiastic about a book, that's a good indicator for its interest level. Yet, the material is still sufficiently challenging so that the student who finishes the course has a good grasp of the vocabulary and the information of the subject. Over a year later, my daughter still remembers things she learned about insects and birds.
My daughter really enjoyed the very "do-able" experiments. She and her dad together built a birdhouse according to instructions in the book, giving her more of her favorite "Daddy time." Other experiments take much less overseeing and still teach lots.
The only drawback to the elementary books is that they do not include tests. If you like concrete assessments rather than just general assignment assessments, you'll have to make your own, which I did.