How to use (and not to use) movement-based indices for quantifying foraging behaviour.

Area of Science:

• Animal behavior
• Movement ecology
• Quantitative biology

Background:

• Moves per minute (MPM) and proportion time moving (PTM) are widely used to quantify animal foraging behavior.
• Existing movement-based indices have fundamental drawbacks that limit their interpretability and accuracy.

Purpose of the Study:

• To identify and address the limitations of current movement-based foraging indices.
• To propose novel methods and analytical frameworks for more robust quantification of foraging behavior.

Main Methods:

• Utilized analytical and simulation models.
• Incorporated individual and species-level foraging data from lizards.
• Developed a bias correction formula for MPM and introduced changes per minute (CPM).

Main Results:

• MPM is constrained by move and stop durations, leading to potential misinterpretation.
• MPM and PTM are interdependent, and certain values in their plane are unattainable.
• MPM exhibits inaccuracy and imprecision; CPM offers a bias-free alternative.
• A new foraging plane based on average move and stop durations was proposed.

Conclusions:

• Current movement-based indices like MPM require careful application and interpretation.
• The novel CPM index and proposed foraging plane enhance the rigor of behavioral studies.
• Guidelines are provided to improve the accuracy and reliability of animal foraging behavior analysis.