Control of migration: Should I stay or should I go?

How individuals know whether, when, where and how to migrate may vary with species and their degree of sociality. In some taxa, where animals migrate together in groups, such as in geese or cranes, the young appear to learn from older birds, including aspects of the seasonal timing, migration routes and wintering areas. In many other species, however, individuals may migrate alone, unaided by conspecifics. These individuals may have little or no opportunity for the cultural transmission or learning of migratory behavior and thus should rely instead – particularly during their first migratory journey – on endogenous, genetically inherited spatiotemporal migration programs encoding when, where, and how far to migrate. We study the control mechanisms of migration using the partially migratory Common blackbird (Turdus merula) by precisely observing the migratory phenotype in the field, performing common garden breeding and translocation experiments.