Ontogenetic stability of inherited migratory directions in a nocturnal bird migrant: comparison between the first and second year of life

摘要

According to current theory young passerine migrants on their first migration are equipped with a genetic programme of duration and direction of migration which enables them to reach their winter quarters independently of adults. The question was investigated whether in birds prevented from gathering migratory experience the genetically determined directional information is expressed only during the first autumn migratory season or whether it is retained as an endogenous directional preference at least throughout the 2nd year of life.