The development of sun compass orientation in young homing pigeons

Summary

A series of clock-shift experiments with young homing pigeons of various ages was performed to determine at what age they normally learn sun compass orientation. The response of untrained pigeons to shifting of their internal clock seems to depend on their age. When the clock-shifted birds were tested at an age of 11 weeks and younger, their departure bearings did not differ significantly from those of controls (Fig. 1, diagrams on the right); in tests with birds 12 weeks and older the characteristic deviation indicating the use of the sun compass was observed (Figs. 2 and 3). Birds that had participated in a short training program, however, used the sun compass at 8 weeks, the earliest age tested (Fig. 1, diagrams on the left). These findings show that the time of development of the sun compass strongly depends on flying experience. Within the first months of a bird's life, it seems to take place after the bird has been confronted with the need to orient, either spontaneously during extended exercise flights around its loft or imposed by training releases.

The departure bearings of the very young, inexperienced birds that did not rely on the sun compass, however, were already oriented homeward. This indicates that the ability to navigate develops independently of the sun compass, before the sun compass is learned.