Karolina Adamska1, Monika Filar2
Bird Migration Research Station, University of GdaĆsk, Przebendowo,
84-210 Choczewo, Poland
bioka@univ.gda.pl 1, biomf@univ.gda.pl 2
Migratory orientation of the Chiffchaff (Phylloscopus collybita) and the
Willow Warbler (Phylloscopus trochilus) investigated with cage experiments
during autumn migration are presented in this study. Tests in the Busse?s cage
were applied to determine their directional preferences. All orientation data were
collected at Kalimok Ringing Station (Northern Bulgaria) in October 2006.
Totally, 246 orientation tests including 218 tests of the Chiffchaff and 28 of the
Willow Warbler were performed.
Tested species showed similar distribution of headings. SSE direction
was observed and also two northern directions NNE and ENE were noted.
However in the Willow Warbler SSE direction dominated, while the Chiffchaff?s
distribution of directions was more dispersed. Additionally the latter displayed
tendency towards SSW as well.
24 individuals of Chiffchaffs, randomly selected were tested twice.
During these analyses we found that birds tested for the second time showed
clearer pattern of preferred headings. Moreover proportion of ?northern?
directions (opposite to the standard direction during autumn migration)
decreased from 54% to 28%. This could suggest that stress connected with
specific conditions of orientation cage tests might have influence on bird
behaviour during the test. That is why during the following test, effect of that
factor discreased.




