Nocturnal Behavior of the Common Loon, <em>Gavia immer</em>

Abstract

Very little is known about nocturnal activity of Common Loons (Gavia immer). Knowledge of both diurnal and nocturnal behavior is needed to gain a complete understanding of their ecology. I used night vision light intensifiers to observe nocturnal behaviors of Common Loons. Results were consistent with the hypothesis that, as visual predators, loons would not forage at night and also that they would spend the majority of their time resting (92%). Loons, however, were just as active locomoting (patrolling) during the night as they were during the day. This suggests daily energy budgets need to be reexamined to incorporate this overlooked aspect of loon behavior. Lastly, loons on large lakes with multiple loon territories spent more time locomoting than loons on lakes that had just a single pair.

Additional Data and Perspectives on Interspecific Aggression in the Common Loon, <em>Gavia immer</em>

“…We assume that a significant expenditure of time and energy is required for such intense patrolling activity, which occurs even through the night (Paruk 2008), and that this activity may not be an example of misdirected territorial behavior, as described by Murray (1971). We propose instead that, unlike many passerine birds (Veen et al 2000;Fitzsimons 2006), loons do not innately discriminate among territorial intruders as to their depredation potential.…”