Hummingbirds are weird. I had assumed that given the size of their brains, they'd be not as smart (naive assumption). But they are curious critters! I have a few who visit my backyard, where I have a chair which noone uses. The other day I decided to sit down in the chair and soak in the sun (a rarity in SF, I might add) with my eyes closed. And soon I heard a low buzzing sound, and what do you know? A hummingbird was hovering about a foot away from my face, observing me. It backed off a bit when I opened my eyes, but did hover around for a few more seconds before flying away. The control they have on their flight is unbelievable. They can hover with so much precision!