The Value of Experimental Approaches in Migration Biology

The past several decades have ushered in a golden age in the study of migration biology, leading to a wealth of descriptive articles that characterize various aspects of migration and its implications for individuals, populations, and ecosystems. However, relatively few studies have adopted an experimental approach to the study of migration, and fewer still have combined lab and field experiments to glean insights into the mechanisms underlying variation in migration behavior and success. Understanding the proximate and ultimate causes of migration timing, energy allocation and optimization, migration success, and fitness is important to aid the conservation and management of wildlife populations by establishing appropriate protections or managing environmental conditions that influence migration. With recent technological advances and miniaturization of animal-borne electronic tracking devices, as well as ground-, water-, and space-based telemetry infrastructure, researchers have the tools necessary to experimentally test hypotheses central to the mechanics of migrations and individual variation therein. By pairing physiological measurements, molecular analyses, and other approaches within an experimental framework, there is the potential to understand not only how animal migrations function but also what differentiates successful migrations from failed migrations and the associated fitness implications. Experimental approaches to migration biology are particularly important, as they will help us to better comprehend and hopefully predict animal responses to environmental and anthropogenic changes by isolating confounding variables that challenge inferences from observations.