SEEN - SE European Bird Migration Network
Who is the first and who is the last on the route? - the Blackcap case
Grzegorz Zaniewicz
Bird Migration Research Station, University of Gdańsk, al. Marszałka Józefa Piłsudskiego 46, 81-378 Gdynia, Poland
e-mail: zidia@wp.pl

The wing length of the Blackcap Sylvia atricapilla is known to show gradual variation, increasing towards the northern parts of the range. Using the biometrical data collected during a 43-year period (1967–2006) we calculated daily average wing length of the Blackcap caught during autumn migration at Bukowo-Kopań (54°21´N, 16°21E´) station, Poland.

The analysis showed differences in time of departure between long- and short-winged Blackcaps. Long-winged birds pass southern coast of the Baltic Sea as first and short-winged birds undertake migratory flight as one of the last. Short-winged individuals are observed twice during the catching season: 1 - before active migration when their fat load is on relatively low level and 2 - in the end of the migration period. Moreover the highest percentage (30%) of birds caught more than once was ringed in the pre-migratory period. They stayed at the ringing site relatively longer than birds ringed when migration was already in course. Also the time between ringing and last catch was significantly longer for short-winged Blackcaps than for the long-winged ones. Both other research and the results of this study indicate that long-winged Blackcaps originate from the northern areas of the species’ range. This pattern is consistent with the leap-frog migration known for the Blackcap.
Created by Pronetix 2006