Exploration-exploitation Learning in Foraging Hummingbirds is Driven by Cumulative Experience and Energetic Costs

Exploration is necessary to gain information about environments, but testing exploration is often overlooked. Previous studies of animal foraging have considered non-rewarded choices to be mistakes representing failure to exploit valuable resources. Here I define several ways to quantify explorative behaviour and use those metrics to test how the probability of explorative choices changes with experience and body mass. I exposed five ruby-throated hummingbirds to an artificial flower array and quantified their exploration across repeated foraging sessions with different reward positions in each session. As the birds gained experience with the experimental paradigm, explorative behaviour started higher at the beginning of each new session despite its overall decrease as the session progressed. Smaller birds were more explorative than heavier birds, consistent with previous tests of foraging success and body mass. These results show that a hummingbird's explorative behaviour changes with body mass and learning resource dynamics through experience.