Migrating young pied flycatchers Ficedula hypoleuca do not compensate for geographical displacements

摘要

The present study tested whether young Scandinavian pied flycatchers, Ficedula hypoleuca, would direct their orientation back towards their southwest-directed migratory route in autumn if displaced by the maximal biologically realistic distance due south or due west. The aim was to clarify the nature of their inherited spatiotemporal orientation programme. Forty-eight young pied flycatchers were caught and tested at Christianso, Denmark, They were then divided into three groups of equal size and orientation, of which one group was displaced due south and another due west, while the third remained as a control at Christianso. Three different experimenters then simultaneously tested their orientation. The birds oriented in the same direction at all localities, showing no signs of compensatory orientation. This result suggests that young pied flycatchers on their first autumn migration use a simple clock-and-compass strategy to reach their wintering area. If this suggestion holds, then all the prerequisites (a compass and an internal clock) for orientation during the autumn migration seem to be known at present, at least at the behavioural level. In addition, the present study provides further evidence supporting the assumption that observations in an orientation funnel reflect the orientation of actual migration. [References: 37]