Pigeon homing: Olfactory orientation—a paradox

Summary

In order to find out whether the different ways that pigeons are raised and maintained at the various lofts affect their orientation behavior, especially the selection of navigational factors, a group of birds was raised according to the procedures of our Italian colleagues in a wind-exposed loft on the roof. The behavior of these R-birds was then compared with that of G-birds living in a garden loft, raised and trained according to the normal Frankfurt procedure. When R-birds were made anosmic by closing the nostril with cotton during transportation and a local anesthetic was used at release, their reaction was similar to that of Italian pigeons: the deviation of their vanishing bearings from the home direction increased significantly, leading to a marked decrease in homeward orientation. In contrast, the orientation of the anosmic G-birds did not differ from that of their controls; their directional selections agreed with those of the controls of the R-group. These data indicate that the conditions of raising and maintaining homing pigeons may be of crucial importance in determining the pigeons' attitude toward olfactory input. Finally, olfactory orientation is discussed; the paradoxical finding that the G-birds, not using olfaction, oriented like the controls of the R-group that did use olfactory input, leads to the question of whether olfactory input really conveys navigational information to the birds.