Summary

The present study analyzes GPS-recorded tracks from pigeons of different age from 11 sites between 3.6 and 22.1 km from the home loft, which reveals changes in the navigational system as the birds grew older and became more experienced. The efficiency of juveniles in their 1st year of life, with only 0.27, was rather low, indicating that the young birds covered more than three times the direct distance home. In the second year, after a standard training program, the efficiency of the same birds increased up to 0.80 and was no longer different from that of older pigeons. The short-term correlation dimension, a variable that reflects the number of factors involved in the navigational process, also increased with age. In juveniles, it is markedly lower than in the other two groups, but even in yearlings, it is still significantly lower than that of old pigeons, indicating that the navigational map of the yearlings is developing further. Our results indicate that the map system, although functional in the first year of life, continues to be become more complex: - older pigeons seem to either consider more navigational factors than younger ones or at least weigh the same factors differently.