Divergence in timing of parental care and migration in barnacle geese

In migratory geese, the extended association of parents and offspring is thought to play a crucial role in culturally transmitting the migration strategy to the next generation. Goslings migrate with their parents and associate closely with them almost until the next breeding season. Families do not break up until spring migration, when the parent--offspring conflict intensifies during preparation for the next generation of offspring. Recently, the commencement of spring migration of the Russian population of the barnacle goose has been delayed by about 1 month. Here, we investigated whether the duration of parental care behavior changed with this alteration in migratory behavior. In contrast to our expectation, we found that parental care terminated well before the commencement of spring migration and that parent--offspring associations were nearly absent during spring migration. We argue that the mechanisms for determining the duration of parental care is different from that determining the commencement of spring migration; hence, we conclude that a divergence in timing has developed between both behaviors. A consequence of this divergence could be that the cultural transmission of migratory behavior is disrupted, possibly playing a role in the recent establishment of new populations of Barnacle geese across the Russian flyway. Copyright 2011, Oxford University Press.