I have a hummingbird feeder hanging near my office window, a source of much amusement. One little female has delegated to herself the role of sentry. She feeds and then sits on the tippytop of the pole holding the feeder. From there she dive bombs other hummingbirds (mostly other females) to keep them from feeding. Occasionally, a ruby-throated male drops in for a drink, but most of boys apparently have already begun migrating. The females usually remain a bit longer, so the war is usually among the girls. Seems like a lot of wasted energy for nothing but territorial rivalry.
