In the last decades, the study of bird migration focused on two main topics; the discovery and description of migratory routes and destinations, and the investigation of the mechanisms that regulate temporal and spatial patterns.
Currently, the focus is more on the ecological and evolutionary aspects of bird migration, and their relevance for conservation policy. While the endogenous regulation and heritability of migration strategies have been studied in detail, their interaction with the environment has received far less attention. Moreover, little is known about the fitness consequences, which are ultimately responsible for individual, population-level and species differences in migration strategies. Of particular relevance are the relationships between the requirement and availability of resources (i.e. fuel), and the need to balance these two factors with the allocation of time between rest and flight. The optimal strategy in this will depend on many factors. Our research on e.g., wheatears, godwits and grey plovers shows that these factors can be successfully studied with the combination of field observations, field experiments and research under controlled conditions. These approaches are further developed within the institute.
In addition, the study of metabolic physiology and the biochemical basis of migratory behaviour has taken flight. Technological advancement in physiological and biochemical analyses in particular has contributed to this, as it now allows us to study these aspects in vivo in relatively small birds. The study of differences between migratory and resident individuals, within the same species, provides especially important new insights in this respect. The scope of this work extends beyond birds, because the biophysical regulation of fat deposition for migration very much resembles the human diabetes type IIb pathology, with the added benefit that fat deposition is an annually reoccurring event.
An aspect of avian migration that has so far received little attention is its importance within the complete life history of an individual. The speed of migration may affect arrival time in the breeding area, which may in turn determine the quality of the obtained breeding territory or nest site, leading to a strong cascade of effects on fitness. Only the study of migration within a complete life-history framework can thus ultimately explain and predict responses to a changing environment.