Figure 1. Garden warblers kept in circular orientation cages in Germany changed their preferred directions during outward migration in autumn in correspondence to the natural situation (centre panel). Tested in August to September they headed south-west while in October to December they changed their preferred direction towards south-east. If birds were kept until the next spring and tested again during spring migratory restlessness, they headed northward (from Bairlein 1996, and sources therein).

Figure 2. Starlings breeding in the Baltic area (A) migrate across northern Germany and Holland (B) to wintering areas in northern France and southern England (C). First-year and adult starlings were caught on their autumn move through Holland (B) and displaced by aeroplane to Switzerland where they were released after ringing (B¢). The young birds (juv) on their first migration continued to travel in their original westerly direction reaching wintering areas in Spain (C¢). In contrast, the adult birds (ad) moved towards their former familiar winter place in north-western Europe. Thus, the young birds followed a given compass direction and did not take into account the displacement, whereas the adult birds were able to compensate for displacement. They conducted goal orientation towards their familiar winter quarters (from Bairlein 1996, and sources therein).

Figure 3. Interactions between celestial and magnetic cues in the development of migratory orientation of songbirds. From Wiltschko et al., 1998.