bethana, we used flying creatures first, and I have to say it was boring at first. I guess for me it was “are we really going to study birds for a whole year???” But then it did pick up, though it would still be my least favorite of the 3 Apologia Elementary animal books.
Having said that, I would suggest a bird ID if you have any birds that visit your yard. You could start a journal with your kids of the ones you see, and that is fun to look back over.
We have this book, which we found extremely helpful, and it is nice hardbound book.
http://www.amazon.com/National-Audubon-American-Birdfeeder-Handbook/dp/0789403374/ref=sr_1_1?ie=UTF8&qid=1344475324&sr=8-1&keywords=national+audubon+north+american+birdfeeder+handbook
Ours is the 1992 edition, but it looks like you can find newer used editions too.
I would say try to stick with it b/c it is a great book that we all enjoyed once we got going, but yes, it is slow at first. 