Multivariate analysis of initial orientation in homing pigeons: Is there a “preferred compass direction”?
Tóm tắt
The mean vanishing direction of homing pigeons of a given release often deviates from the home direction considerably. Any kind of geographical systematic in these deviations might give us a hint on the distribution of the information involved in the homing process. Analysis of releases arranged symmetrically around the home loft with methods of circular statistics could not resolve the pending question of site-specificity vs. directional effects in the initial orientation of homing pigeons unambiguously. In part, this ambiguity comes about by the facts that
Circular statistics are unable to resolve the impacts of these nested factors in the experimental design employed at present. In separate analyses of mean vanishing directions and lengths of mean vectors with nested analysis of variance, site-specific effects could be disentangled from directional characteristics. According to this analysis for pigeons from our lofts at Tübingen the angular deviations of the mean vanishing direction from the home direction is site-specific, whereas the scatter of the bearings depends on the cardinal direction of the release site with respect to home. The application of multivariate statistics to circular data may not be possible in all cases. But once they are, these multivariate methods will help to separate the confounding effects of different experimental conditions in the multi-factorial system of pigeon homing.
Tài liệu tham khảo
Batschelet, E. (1981): Circular statistics in biology. London, N. Y.
Foa, A., S. Benvenuti, P. Ioalé &H. G. Wallraff (1984): Geographical and temporal variability in pigeon homing. Behav. Ecol. Sociobiol. 15: 25–34.
Ganzhorn, J. U., &K. Schmidt-Koenig (in press): Initial orientation of homing pigeons around Tübingen. In:K. Schmidt-Koenig, K.-L. Schuchmann &R. v. d. Elzen (eds.): Internat. 100. Jahresversammlung DO-G, Bonn.
Keeton, W. T. (1973): Release-site bias as a possible guide to the “map” component in pigeon homing. J. Comp. Physiol. 86: 1–16.
Kiepenheuer, J., N. E. Baldaccini &E. Alleva (1979): A comparison of orientational and homing performances of homing pigeons of German and Italian stock raised together in Germany and Italy. Monitore Zool. ital. 13: 159–171.
Kramer, G. (1957): Experiments on bird orientation and their interpretation. Ibis 99: 196–227.
Ditto (1959): Recent experiments on bird orientation. Ibis 101: 399–416.
Lorenz, R. J. (1984): Grundbegriffe der Biometrie. Stuttgart.
Michener, M. C., &C. Walcott (1967): Homing of single pigeons — analysis of tracks. J. exp. Biol. 47: 99–131.
SAS/STAT (1987): Guide for Personal computers. Cary.
Schmidt-Koenig, K. (1961): Die Sonne als Kompaß im Heim-Orientierungssystem der Brieftauben. Z. Tierpsychol. 68: 221–244.
Ditto (1963): On the role of the loft, the distance and site of release in pigeon homing (the “cross loft experiment”). Biol. Bull. 125: 154–164.
Ditto (1987): Bird navigation: has olfactory orientation solved the problem? Quart. Rev. Biol. 62: 31–47.
Ditto, &C. Walcott (1978): Tracks of pigeons homing with frosted lenses. Anim. Behaviour 26: 480–486.
Siegel, S. (1956): Nonparametric Statistics. Tokyo.
Sokal, R. R., &F. J. Rohlf (1969): Biometry. San Francisco.
Walcott, C., J. L. Gould &A. J. Lednor (1988): Homing of magnetized and demagnetized pigeons. J. exp. Biol.
Wallraff, H. G. (1959): Örtlich und zeitlich bedingte Variabilität des Heimkehrverhaltens von Brieftauben. Z. Tierpsychol. 16: 513–544.
Ditto (1970): Über die Flugrichtungen verfrachteter Brieftauben in Abhängigkeit vom Heimatort und vom Ort der Freilassung. Z. Tierpsychol. 27: 303–351.
Ditto (1974): Das Navigationssystem der Vögel. München, Wien.
Ditto (1978): Preferred compass direction in initial orientation of homing pigeons. In:K. Schmidt-Koenig &W. T. Keeton (eds.): Avian migration, navigation and homing. Berlin, Heidelberg, N. Y.: 171–183.
Ditto (1979): Goal-oriented and compass-oriented movements of displaced homing pigeons after confinement in differentially shielded aviaries. Behav. Ecol. Sociobiol. 5: 201–225.
Ditto (1986): Directional components derived from initial orientation data of inexperienced homing pigeons. J. comp. Physiol. A 159: 143–159.
Wiltschko, R., &W. Wiltschko (1985): Pigeon homing: Does initial orientation include a “preferred compass direction”? J. comp. Physiol. A 157: 469–476.
Ditto, &C. Walcott (1987): Different effects of olfactory deprivation in different countries. Behav. Ecol. Sociobiol. 21: 333–342.