I can't answer your last question, but thought I'd comment anyway. 500mm, wow, I've only gone as far as 200mm. With 500, do you have to use a tripod? They are all fine shots, in spite of your dilemma. On my monitor though, it looks like #1 and #3 could have some more contrast. Or maybe it's #3 looks a little blue. But even if it is, that would be an easy fix. Love that bird! What a cool surprise!