Figure 2.

Orientation of robins of group A2 in spring. The tests took place in the local geomagnetic field unless otherwise indicated. Bi, binocularly tested (control); L, tested monocularly left-eyed; 6peL, tested monocularly left-eyed after 6 h pre-exposure with the right eye covered; 6peLvi, same as for 6peL, but tested in a magnetic field with the vertical component inverted. Symbols as in figure 1.