Cylones and pelagic seabird movements

Abstract

Records of Fulmar Fulmams glacialis, Sooty Shearwater Puffinus griseus, Gannet Sula bassana and Kittiwake Rissa tridactyla, off Kullen in south Sweden, in the decade 1970 to 1979 have been analyzed with respect to meteorological conditions. A causal model describing the occurrence of flap-gliding pelagic seabirds off Kullen is proposed, based upon evidence of (1) close association of these birds with eastward travelling deeper cyclones; (2) restrictions of bird movements due to certain wind directions and velocities; (3) absence of documented cyclonic centre passages south of Latitude 58ON at Longitude 10° in connection with observations of birds; (4) earlier flight behaviour studies. A clockwise movement of birds in the Kattegat is ascribed to the interaction of (a) prevailing wind conditions in cyclones, (b) inertia of wave topography, (c) the birds' flight technique. The apparent conformity between the successive clockwise coastal pattern of movement of flap-gliding pelagic seabirds in the Kattegat and the North Sea is considered.