Fig. 5. Summary of orientation experiments (in blue), homing experiments (in red) and neurophysiological studies (in black) examining light-dependent magnetoreception in birds, published until 2001. Also included are the results of the present study (in green). The graph shows the wavelengths and intensities under which birds were tested in orientation experiments and in an electrophysiological study (filled symbols indicate experiments revealing significant orientation, and open symbols indicate experiments revealing disorientation). The triangles indicate the average peak wavelength, and the horizontal bars indicate the half bandwidth (/2) of the spectrum, if available. Diamonds indicate oriented behaviour into directions significantly different from the seasonally expected migratory direction. Magnetic responsiveness of units of the basal optic root (nBOR) in the electrophysiological study on pigeons by Semm and Demaine (1986) is indicated by crosses (larger crosses indicate peak responses). The symbols refer to the following published orientation experiments: full-spectrum light at intensity M (Wiltschko et al., 1993; Wiltschko and Wiltschko, 1995; Munro et al., 1997; Rappl et al., 2000) and intensity XXL (Möller et al., 2001); blue light at intensity M (Wiltschko et al., 1993; Wiltschko and Wiltschko, 1999, 2001; Rappl et al., 2000), and intensity XL (Wiltschko and Wiltschko, 2001); turquoise light at intensity M and intensity XL (Wiltschko and Wiltschko, 2001); green light at intensity S (Wiltschko et al., 2000a), intensity M (Wiltschko et al., 1993, 2000a,b, 2001; Wiltschko and Wiltschko, 1995, 1999, 2001; Munro et al., 1997; Rappl et al., 2000), intensity L (Wiltschko et al., 2000a,b) and intensity XL (Wiltschko et al., 2000a,b; Wiltschko and Wiltschko, 2001); yellow light at intensity M (Wiltschko et al., 1993; Wiltschko and Wiltschko, 1999, 2001; Rappl et al., 2000) and intensity XL (Wiltschko and Wiltschko, 2001); and red light at intensity M (Wiltschko et al., 1993; Wiltschko and Wiltschko, 1995; Munro et al., 1997; Rappl et al., 2000; Möller et al., 2001). The asterisk refers to the study by Möller et al. (2001) where significant mean orientation was found after pre-exposure to red light only. The homing experiments refer to those of Wiltschko and Wiltschko (1998).

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