At the very end of several paragraphs' worth of information on hummingbirds in the Peterson guide, the last sentence is just one word: "Pugnacious." I always find that so delightfully funny. Here are these gorgeous, fairy-like creatures, and at the same time they are really fierce. Aside from the way they chase each other off, I've seen them chase chickadees out of the bird bath when they decided they wanted to drink, and you better believe those chickadees got right the hell out of there. I hear they've been seen to go after owls and hawks.