Are dragonflies territorial?

I was sitting out back at my (getting rather small, we haven't had much
rain) pond this afternoon and watched the dragonflies. There are oodles of
them that hang out around here, green ones, blue ones, speckled ones, a
bunch of different kinds and sizes. Some of the green ones would fly
underneath my chair and around me keeping the air as free of biting bugs as
any repellent I have ever used. It was sort of like having my own little
insect air force to protect me. As I sat and looked out over the pond,
however, there was one and only one dragonfly flying. It was big and it
was red. It would patrol over the pond, and then when it wanted to rest it
flew up to a nearby pine tree. Other dragonflies would start to hover over
the pond, and then the red one would leave it's perch and dive and chase
the other dragonflies until they left. Then it would patrol over the pond
for a bit, and then go back up into the pine tree. Other dragonflies would
start to hover over the pond again, and the red dragonfly came out of the
tree to chase them away again. This happened over and over, and this isn't
the first day, either. Are all dragonflies like this, or do I just have an
obnoxious bully at my pond?

Galen Hekhuis NpD, JFR, GWA
Hell hath no fury like a bird in the hand.