Circle Dancing

This morning we had a visiting loon, very close to the nest site. A third loon on a territory is always trouble, especially when the pair is on the nest or has chicks in the water. A visiting loon will enter a territory to evaluate it. It will only confront the resident pair if it is interested in driving out the member of the pair that is the same sex and thereby taking over the territory.
The circle dance is the first step in a visitor sizing up the competition. As you can see in this clip, it is very regimented in form. It consists of the participants swimming in a circle and synchronous diving. This way each loon can judge the strength and agility of the other.
In this case, the visitor decided it wasn’t worth escalating matters and backed off after a few minutes. In other cases, the end result could be an aquatic wrestling match, a wing-rowing chase, or even a stealthy submarine attack, using the bill to to impale the breast of the opponent. These encounters sometimes end in the death of either the visitor or the resident. But fortunately this incident ended quickly and the pair was able to get back to nesting duties.