Energy selection functions: modelling the energetic drivers of animal movement and habitat use

Energetics are a key driver of animal decision-making, as survival depends on the balance between foraging benefits and movement costs. This fundamental perspective is often missing from habitat selection studies, which mainly describe simple correlations between space use and environmental features. To address this gap, we present a new model, the energy selection function (ESF), to assess how moving animals choose habitat based on energetic considerations, thus incorporating a key aspect of evolutionary behaviour into habitat selection analysis. We outline a workflow, from data-gathering to statistical analysis, and demonstrate the model’s utility with a case study of polar bears. Our findings show how cost-minimization may arise in species that inhabit environments with an unpredictable distribution of energetic gains. Because of its close links to existing habitat selection models, the ESF is widely applicable to any study system where energetics can be derived, and has immense potential for methodological extensions.