Who Decides Where the Nest Goes?

In contrast to the social and vocal behavior, loon nesting behavior is a low-key activity, as the following video shows. This makes sense, as the birds do not want to draw attention to their nest site. When searching for a nest location, male and female remain close together, as they probe shorelines, islands or emergent vegetation that could support a nest. A pair member that has found a potential site gives deep head bows. You should also just be able to hear the soft “maa” calls emitted by pair members while nest-searching. The loons give a few vigorous head shakes during the video, which are not part of loon nesting behavior but are simply their way to get a moment of relief from the blackflies that harass them in May.

Intuitively, one might suppose that female loons should decide where to lay their eggs, as they are the ones that produce them. However, it is actually male loons who are in charge of nest placement within the territory. This behavioral pattern has the interesting consequence that males benefit more than females from remaining on a familiar territory, where they can reuse successful nestsites from previous years and avoid nestsites where predators ate the eggs before they could hatch. For their part, female loons gain no measurable benefit from breeding on a lake where they have bred before, as their reproductive success depends upon their mate’s knowledge of nestsites, not their own.