Unravelling migratory connections: the next level.

Migration is widespread among birds, and the strength of the link between the breeding and wintering grounds, migratory connectivity, influences many ecological and evolutionary processes. Despite its importance, migratory connectivity is poorly estimated for most species. Traditionally, visual observations and bird ringing have been used to monitor migration, but these methods require more effort for relatively little return. Genetic markers and stable isotope signatures have increasingly been used to study connectivity. Each approach has its distinct strengths and weaknesses, and as is often the case, a combination may yield the most insight. In this issue of Molecular Ecology, Rundel and colleagues (2013) present a novel Bayesian statistical framework in which genetics and stable isotope data can be combined to improve the assignment of individuals to different winter or breeding regions. The development of such new statistical methods combined with the increasing number and ease of access of isotopic and genetic data sets will greatly enhance our understanding of migratory connectivity. Add to this the developments of miniature devices to track movements of individuals, and the field is destined to make major progression in the decades to come.