Male Canada geese are very aggressive. During mating season they choose a female (if they do not have one, as they are monogamous) and defend her (and later the nest) against all rivals (even other species).
This scene started with a couple sleeping at the edge of the pond, when suddenly a second pair loudly came swimming across to chase the couple away. The couple did not budge, and instead it lead to a long fight about whom the pond belongs to. I was standing right next to them, and they were a) loud and b) scary!
