The bird I have that I get the maddest at is smart. She's a GLW named Daisy, but I've nicknamed her b*tchy-poo, because she's such a bully to the others, especially my newbies. I've shut her out of the run before for bullying my little girls, and after pacing back and forth trying to figure out how to get back in for a minute or so, she'll go all the way around our 36 ft. long garage/workshop AND our lean-to junk/storage area to sneak in the back door of the run. She's got evil smarts.
