Gravity anomalies without geomagnetic disturbances interfere with pigeon homing--a GPS tracking study.
The gravity vector theory postulates that birds determine their position to set a home course by comparing the memorized gravity vector at the home loft with the local gravity vector at the release site, and that they should adjust their flight course to the gravity anomalies encountered. As gravity anomalies are often intermingled with geomagnetic anomalies, we released experienced pigeons from the center of a strong circular gravity anomaly (25 km diameter) not associated with magnetic anomalies and from a geophysical control site, equidistant from the home loft (91 km). After crossing the border zone of the anomaly--expected to be most critical for pigeon navigation--they dispersed significantly more than control birds, except for those having met a gravity anomaly en route. These data increase the credibility of the gravity vector hypothesis.
Institute of Anatomy, University of Zurich, 8053 Zurich, Switzerland Max Planck Institute for Ornithology, D-78315 Radolfzell, Germany.
Nicole
N
Blaser
Ukrainian Geological Institute, 02088 Kiev, Ukraine.
Sergei I
SI
Guskov
Ukrainian Geological Institute, 02088 Kiev, Ukraine.
Vladimir A
VA
Entin
Institute of Anatomy, University of Zurich, 8053 Zurich, Switzerland.
David P
DP
Wolfer
High-Technologies Institute, 03038 Kiev, Ukraine.
Valeryi A
VA
Kanevskyi
Institute of Anatomy, University of Zurich, 8053 Zurich, Switzerland Department of Physiology, School of Laboratory Medicine and Medical Sciences, KwaZulu-Natal University, Durban 4000, South Africa hplipp@anatom.uzh.ch.
Hans-Peter
HP
Lipp
D000818:Animals; D010856:Columbidae / Q000502:physiology*; D005260:Female; D005426:Flight, Animal; D040362:Geographic Information Systems / Q000295:instrumentation*; D006112:Gravitation; D006702:Homing Behavior / Q000502:physiology*; D008297:Male; D009949:Orientation; D014455:Ukraine
Biological GPS; Columba livia; Gravity vector; Gravity-based navigation; Horizontal component; Navigation strategies; Object following; Orientation