Autumn Migration Dynamics and Biometrical Differentiation of the Dunnock (Prunella modularis) Passing the Southern Baltic Coast
The aim of this study is to determine biometrical differentiation among Dunnocks caught at the two ringing sites (Bukowo-Kopań and Mierzeja Wiślana) located on the southern Baltic coast. The distance between those two stations covers 190 km. The material was collected during autumn fieldwork of the Operation Baltic in 1961-2003. The material used for biometrical analysis comprises only immature birds from the period of the most intensive migration, when the numbers of caught individuals allowed to compare the results for both stations. The seasonal dynamics at both sites was pooled for 43 years of catching. Medians of autumn migration for the stations were significantly different. A shift of the median for the eastern site (Mierzeja Wiślana) by 6 days after the median for the western site (Bukowo-Kopań) suggested different origins of birds migrating through the stations. The analysis of standard deviations for the studied biometrical parameters confirms an intra-seasonal change in proportions of birds probably originating from different areas in Europe.