Figure 3.

Orientation of robins during their second autumn migration. All tests took place in the local geomagnetic field. (a) Robins of group A1 caught in autumn the year before; they were unfamiliar with their winter quarter (same birds as in figure 1); (b) robins of group Sp caught in spring during return migration; they were familiar with their goal. Bi, binocularly tested (control); L, tested monocularly left-eyed; 6peL, tested monocularly left-eyed after 6 h pre-exposure with the right eye covered.