Ruby-Throated Hummingbird 2
They expend an exceptional amount of energy just fighting with each other. I watched as two of them faced off about one inch from each other. Then they flew straight up until they were just about out of sight. At times it appears as though they struck each other with their beaks. It happens so quickly that you can’t actually see it; you just hear a clunking sound. They weigh in at one tenth of an ounce so you would think that they wouldn’t be so fearless.