So much birds! I like the birds of prey, include the Old world vulture, the eagle, and the falcon! But the New World vultures were strongly resembled the Old World vultures, but they weren't closely related to. Sorry to bug you.
If you don't mind, I'd like to ask: How has Lulu.com has worked out for you? I read how to upload something there. I wasn't sure if it was worth it to try one small book on SketchUp. I see that you have a number of really good items up there; so, even if you make only a little bit of money on one item, you probably sell a lot of them.
Lulu is fantastic for me. It's a really good thing. Of course it depends on how much audience you have, but you really lose nothing having a book up there, some end up listed on amazon, and you can also offer ebooks up there.
It's like a "How to Draw" version of Sibley! XD I love it. Thanks! There's just too much to cover, so I absolutely cannot complain about any details left out. I'm just impressed that you were this detailed at all for a general Birds tutorial. Really, it's kind of impossible to generalize birds. As you've found out. XD *FAVES*