Home Loft Research Articles

Tracks of pigeons homing with frosted lenses

Pigeons were equipped with frosted contact lenses that prevented any detailed view of landmarks. They were tracked during their homing trips by ground based and airborne radiotelemetry. A total of 74 experimental birds were released from various directions less than 20 km from home. Nineteen pigeons returned to the loft, 18 stopped en route and were retrieved, and 37 were lost. In addition to five tracks of birds wearing clear lenses, 18 birds wearing frosted lenses were tracked. These experimental pigeons, despite their frosted lenses and severely restricted vision, flew generally toward the home loft. Whereas many of these birds landed in an area near the loft, no bird that we tracked landed on the loft itself. These results support the view that pigeons use a navigation system that does not require detailed vision and is accurate enough to lead birds to within 0·5 to 5 km of their goal.

Homing pigeon orientation influenced by deflected winds at home loft

An attempt to repeat studies performed by Baldaccini et al. (1975b) in which pigeons exhibited predictably deviated mean vanishing bearings after prolonged exposure to deflected wind flow is reported. In four sets of pooled release data, deflections in mean bearings as predicted by the olfactory hypothesis of pigeon homing were observed. It is concluded that the time spent in such deflected-wind environments significantly alters some component of the birds' initial orientation mechanism.

Regional expression of directional preferences by experienced homing pigeons

The behaviour of experienced homing pigeons immediately following release was examined temporally at a single release point and spatially from a gridwork of release points. Directional preferences did not diminish with repeated flight experience from the same release point nor did they shift significantly within a release day. Directional preferences varied systematically as a function of both distance and direction of displacement from the home loft and seemed to represent a varying compromise between flying to the NNW and flying toward home. Homeward directedness of vanishing bearings, time to leave the release point and time to reach home are all superior for releases conducted to the south and southeast of the loft.

Sun Navigation in Homing Pigeons—Attempts to Shift Sun Coordinates

ABSTRACT Small time errors in the biological clocks of pigeons appear to have no effect on their navigation. An error of 2 h seems to shift the pigeons’ orientation as predicted by a suncompass hypothesis, but 6 h shifts gave initial orientation that was too scattered to analyse. Alteration of the apparent sun altitude with mirrors at the loft was without effect on navigation. The administration of 30% D2O in the pigeon’s drinking water combined with a random light schedule and holding at a westerly point had no effect on the pigeon’s homing. We conclude that the pigeon’s navigation is probably not based on either the sun or on accurate sense of time at the home loft.

The orientation of homing pigeons in relation to change in sun declination

The sun navigation hypothesis ofMatthews is briefly reviewed with special reference to his sun occlusion experiment which supports this hypothesis. The results of a similar experiment are presented in which 13 young pigeons were kept from sight of the sun during a seven day period including the fall equinox while the sun height at noon decreased 3° 6.7′. When the birds were released from a point 93 km. south of their loft they were exposed to a noon sun height equal to that of a point north of their home loft eight days earlier. Nevertheless they showed a northward orientation as did the 10 control birds with no difference in homing performance between the experimental and control groups. These results are not in agreement with those ofMatthews and do not support his sun navigation hypothesis.