Behaviour of the Marsh Harrier during the post-fledging period

摘要

Thirteen individually marked Marsh Harriers (5 adults and 8 fledglings) from three families were observed on the calcareous marshes near Chelm in eastern Poland. Young harriers start flying at 37-42 days after hatching. Young males started to fly earlier then females. Duration of the post-fledging period (PFP) was 25 to 37 days, on average 32 days. Daily numbers of fledging flights increased up to the third week and then decreased. Total time of flight increased up to the fourth week of the dependent period. The number of the flights in last week before departure from breeding places was significantly less than in the former weeks. The maximum time of the single flights increased from the beginning up to fourth week. The maximum time of the flight observed in a young bird was over 32 min.