Practice question

Optimal patch departure occurs when the instantaneous rate of resource gain in the current patch falls to the average rate available in the environment, including travel time. This rule maximizes long-term gain rather than requiring complete depletion. Remaining until a patch is empty is often inefficient because the last items are difficult to find, while leaving too early sacrifices readily available food. The phrase “leave at maximum gain rate” is a simplified description of leaving at the point that maximizes the overall intake-rate tangent in the marginal value theorem. It should not be interpreted as departing at the initial instantaneous peak, which would imply virtually no patch exploitation. The relevant evidence concerns process rather than wording alone. Linking the described pattern to energetic returns, fitness consequences, or receiver responses makes the inference biologically coherent and distinguishes it from the competing alternatives. Ecological categories are simplified models, yet they remain valuable when their assumptions are stated. The selected description captures the dominant net effect, while real systems may vary with density, habitat, life stage, and environmental conditions.