Social Migration of Goose Families
Every year, millions of migratory geese travel thousands of kilometres between their Arctic breeding grounds and temperate wintering areas, making use of several stopover sites en route. Contrary to other migratory species, goose family groups stay together through their first migration, often even longer. It is expected that knowledge about migration and foraging sites is passed on in family groups from parents to chicks. Within individuals, migration routes and timing have been shown to be highly consistent. However, it is not clear if that is also the case between family members, i.e. that goose chicks use the same migration routes and timing as their parents after they have separated. We aim to disentangle those questions by studying life time tracks and social movement patterns in family groups of geese.
In collaboration with the Russian Academy of Sciences, the institute Alterra in the Netherlands and the Dutch Society of Goose Catchers, we catch family groups of larger white-fronted geese (Anser a. albifrons) and equip them with high resolution GPS/ACC transmitters. We follow their tracks throughout the year in order to understand migration timing in relation to environmental factors and social status of the geese. We compare movement tracks of the members of single families in their first year’s migrations and determine indices of coordination and leadership. Furthermore, we examine when and how young geese split off from their parents and how members of the same family find each other after being separated. In the future, we hope to be able to compare life-time tracks of geese that were tagged as young and compare them to tracks of their parents. The results of our study will be crucial for improving the conservation of larger white-fronted geese, get an insight in their ability to adapt to the changing climate and habitat and provide an understanding of mechanisms of coordination in family groups of large birds.