All of us know loons on Sylvia by their haunting vocalizations. There are three long-distance calls: the wail, the tremolo, and the yodel. Each one plays a role in establishing and maintaining the breeding territory.
Recognizing Loon Calls
Common loons are large, fish-eating birds that winter on the ocean but breed on freshwater lakes. Loons have been studied for years, but only in the last fifteen years do we have a large enough population of banded individuals to begin to understand the details of their behavior.
Breeding territories can be founded on vacant lakes by replacing a missing pair member or by actively evicting a member of the pair. When an intruding female takes over a territory, the displaced female moves to an adjacent lake. In contrast, about 30 percent of territorial battles are fatal when the intruder is male. If a loon is killed, it is always the resident male, never the intruder. We don't know why there is this asymmetry in the behavior of the two sexes. But since the male loon seems to select the nest site with improving reproductive success every year, this may be the reason.
Video from Cornell University - eight short videos detailing loon behavior that offers insights into the life of our Sylvia Lake loons.