Directional Preferences of the Robin (Erithacus rubecula) and the Blackcap (Sylvia atricapilla) During Autumn Migration at Arosio (N Italy) in 2005

Results of orientation tests of nocturnal migrants with the use of Busse's cage (Busse 1995, Busse 2000) are described in this paper. That method enables to study directional behaviour of nocturnal migrants during daytime. The aim of these studies is the description of directional preferences of the Robin and the Blackcap at the ringing station Arosio, northern Italy. Totally, 220 orientation tests for the Robin and 77 for the Blackcap were performed. Tested species have shown differentiation of directional preferences. Distribution of directions for the Robin is very clear. One direction was preferred - SSE direction (34%). For the Blackcap the distribution of headings was more complex, but two main directions could be distinguished - SSW (23%) and WSW (22%). Migration patterns of both these species in Europe are complicated. Birds migrating through northern Italy should be regarded as different migrating populations (Remisiewicz 2002, Mokwa 2004). However, migration pattern of the Robin was strongly determinated in one SSE direction, which indicates the Apennine Peninsula. Blackcap followed two directions, which indicate western winter quarters. Obtained results stood in accordance with other data, such as recoveries. Although the obtained results seem to be very interesting and promising, only intensive studies, especially in areas indicated by tested birds, could give information about migration pattern of these species.