SEEN - SE European Bird Migration Network
Differentiation of directional preferences of the Robin (Erithacus rubecula) during the autumn migration through the Beskid Niski Mountains

Karolina Adamska, Monika Filar

Bird Migration Research Station, University of Gdańsk, Poland

Data were collected at Akcja Carpatica ringing station (49º32’N 21º34’E) located in the Beskid Niski Mountains (S Poland) in 2000–2003. In total, during six autumn seasons 624 orientation tests were performed with the Busse’s method (Busse 1995) for studies on directional preferences of night migrants. Data were elaborated with a non-standard method for circular data evaluation proposed by Busse and Trocińska (1999) that could be applied to multimodal distributions. Tested birds showed high proportion (more than 60%) of the reversed directions for the autumn migration. Thus we decided to analyse the headings’ pattern after applying the reversing procedure (adding 180° to all northern directions). This is based on an assumption that birds show axial behaviour in the cage. In all studied seasons differentiation of the directional preferences could be observed. Such directions as: SSE, SSW, ESE and WSW were preferred. To demonstrate seasonal directional preferences changes during the migration period, autumn seasons of 2000 and 2003 were divided into periods reflecting migration waves. Tested Robins indicated intra-seasonal changes and differentiation of the directional preferences between all studied years.

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