ON THE ROLE OF THE LOFT, THE DISTANCE AND SITE OF RELEASE IN PIGEON HOMING (THE "CROSS-LOFT EXPERIMENT")

¹ Dept. of Zoology, Duke University, Durham, N. C., and Max-Planck-Institut f. Verhaltensphysiologie, Abt. Mittelstaedt, Wilhelmshaven and Seewiesen, Germany

1. Five lofts which formed a symmetrical cross, with several kilometers' distance between the lofts, were established. Releases were performed with birds from all lofts along the extensions of the axes of this cross. From points close to the cross, birds from certain lofts would face identical home directions but different distances whereas birds from other lofts would face different directions but similar distances. The effect of such controlled interrelations upon initial orientation and homing success below 100 km. was studied.

2. A diversity of directional preferences, but no consistency between the variations in distance and direction from home and direction of headings, was found.

3. A loft-specific basis for the differences and changes in vanishing behavior and homing success is suggested. Its cause is unknown. Previously suggested explanations, such as large scale topographical, geophysical, and meteorological factors and variations, are hardly applicable to these observations.

4. There may be some improvement of homeward directedness of headings with increasing distance; however, random vanishing patterns were observed up to the longest distances tested (84 km.).

5. A slight general west tendency, apparently modified by loft-specific components, was observed for the Durham area.