Why Do Groups of Loons Congregate on the Lake?

 Photo by Gio Bartlett / Unsplash

Question:

At our cabin in northern Minnesota, we normally have only one pair of loons that nest on the lake. However, one summer we began noticing eight to 10 loons gathering together on the lake for an hour or so, diving and swimming. We call it “The Loon Breakfast Club.” After the morning breakfast stop, they fly off. Is this behavior unusual? Are they gathering to socialize?

– Barb, Minn.

Answer:

In summer, many loons begin each morning by flying to a rendezvous lake to participate in some social bonding, like you have observed.

For those who haven’t witnessed it, a loon social gathering is an impressive event. As loons arrive, first flying past for a quick assessment and then gliding in silently, fellow sharp-eyed birds on the water greet them with an excited “hoot,” a salutation given nearly an octave higher than the usual contact call. With toes dangling and body held upright, each loon comes in on a high-speed landing that starts with the tips of their feet dragging in the water and ends in a chest-first splashdown. 

Coming to rest, each loon begins to seek out others, and they all begin to congregate into a loose raft of loons. In the skies above, other loons call in a hurried tremolo, signaling their intent to land and join the group, which settles into a routine that looks much like a dance.

The whole raft then swims about in a sort of slowly turning “square dance,” bills turned downward, red eyes looking in toward the middle of the circle. When one loon dives, the rest swim nervously, plunging faces underwater to track the diver’s progress. With poetry, grace and perhaps a dose of mistrust, the swimming circle erupts suddenly with loons splashing, chasing, dipping, diving and calling wildly.

The rogue loon suddenly erupts on the waves, pursuing the tail of another, and the two chase each other. Sometimes they pursue one another tirelessly over the water, wings churning froth in a competitive breaststroke until one bird is driven away from the group. Other times, the loons diffuse tension with an assortment of intense behaviors on splayed wings, rising powerfully from the water and calling.

Scientists have suggested a number of hypotheses for these social gatherings, including the possibility that the loons are preparing for fall migration. However, the apparent reasons for loon groups are often inconsistent. Maybe the “square dance” behavior represents a sort of aquatic chicken coop, a tussle for pecking order. Perhaps it involves a bit of play and learning, important skill-building behavior in the animal kingdom. It is even possible that the birds are already working on settling next year’s mating-season issues.