If you are following the events on Blue-Southeast, you will recall that the male there, who was caring for two large, healthy, 5-week-old chicks, was evicted and seriously injured by an unbanded male, who drove him off and seized territorial control. The new male was an indifferent stepfather, initially pecking at his stepchicks and then simply ignoring them. Meanwhile, the displaced father licked his wounds on the west side of the lake and waited for the situation to improve. Things did get better; after a few weeks of limited interaction with the female, who was preoccupied with rearing her two voracious youngsters, the new male drifted away, permitting the displaced male, who quickly regained his health, to resume parenting and rejoin his mate.
While I am delighted to see the old, evicted male pick himself up, dust himself off, and recover his position, the behavior of the usurping male on Blue-Southeast presents a puzzle. Why would an outside male hurl himself into a violent, dangerous battle, win a new and productive territory, and then relinquish it shortly afterwards without a fight? We do not understand such behavior well. However, it is possible that a young male that is physically superior to a another male with a territory can battle and defeat that male without great danger, settle and live within the territory for a time, and then decide that the breeding space does not suit his needs. I think that the preferences of loons for natal-like lakes and, later, lakes of certain clarity, might hold the key to understanding this curious behavior.
We will keep collecting data in an effort to understand why loons fight fiercely for territories and then sometimes give them back to owners. Meanwhile enjoy this video of the Blue-Southeast female enduring relentless begging by one of her chicks as she forages for it.