These were the two books I also couldn’t find at the library or anywhere reasonably. But I’m finding that Outdoor Secrets is very flexible. The additional books are only meant to enhance the use of the actual Outdoor Secrets book, so there’s no reason you couldn’t substitute a different book on the topic, or skip the additional book altogether and just use Outdoor Secrets, or use internet resources. I was able to find another book about trees (haven’t gotten to wasps yet) and we’ve just spent a lot of time outside looking at trees, collecting leaves (we were fortunate to be able to visit friends in a part of the US where the leaves actually change color, as they don’t where we live), feeling bark and doing rubbings, climbing trees…..you get the idea.