, Volume 5, Issue 2, pp 201-225

Goal-oriented and compass-oriented movements of displaced homing pigeons after confinement in differentially shielded aviaries

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Summary

Young pigeons were kept in an aviary from the time of weaning until the time of displacement 3–5 months later. The two compartments of the aviary were differentially shielded by surrounding walls, and birds of both compartments were released simultaneously. During six years, seven types of shieldings were used (Fig. 1). Releases were conducted at four sites in the cardinal directions (distances about 100 and 30 km, respectively). Initial bearings and distributions of recoveries led to the following conclusions (Figs. 3 and 4):

  1. Visual shielding of the environment up to about 10° above the horizontal plane does not influence long-distance orientation, provided that the shielding does not also impair the airflow through the aviary.

  2. Homeward orientation is drastically reduced if the aviary is surrounded by walls made of glass.

  3. Homeward orientation from all four directions persists if the pigeons lived in corridors between two solid walls permitting airflow either along the N-S axis or along the E-W axis.

  4. The preferred compass direction (PCD) of pigeons which lived in this aviary in unscreened conditions is SSW. In the initial bearings, this PCD is more pronounced than the tendency toward home.

  5. The PCD is reversed to NNE in pigeons which lived in a corridor open at east and west (but is unaffected by a N-S corridor).

  6. The results obtained with the corridor aviaries do not support the olfactory navigation hypothesis as it stands so far (cf. Papi, 1976).

Some aspects of circular statistics are discussed in the Appendix.