TIMING OF AUTUMN MIGRATION AND BIOMETRIC CHARACTERISTICS OF MIGRATING POPULATIONS OF EUROPEAN ROBIN (ERITHACUS RUBECULA L., 1758) IN NORTH-EASTERN POLAND

摘要

We studied the autumn migration of the European robin (Erithacus rubecula) through north-eastern Poland. During the study period 2002-2004 we analysed a total of 2375 individuals: 1991 first-year birds and 349 adults. First-year birds had shorter wings than adults. Body condition was influenced by age, year of migration fat content and arrival time. Our results show that first-year birds arrived earlier, had low-fat levels and were in a comparatively poorer body condition to that of the adults and were less effective foragers. Stopover length decreased during the migration season for both age groups as a result of rush to their wintering areas because of winter approach. We found that adult females arrived later than adult males.