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Fig. 1. Deviations from the expected directional shifts of birds that are relying
on the magnetic compass in cue conflicts between magnetic and sunset cues
during the migratory period (Table
2A, studies not listed in parentheses). The magnetic field shifts
are divided into counterclockwise (CCW) and clockwise (CW) shifts and into
`against the sun' (AS) and `with the sun' (WS) shifts, since CW and CCW shifts
should be interpreted differently by birds living in the northern and southern
hemispheres (see text). Filled triangles indicate 90°, open triangles
120° and the rhomboid 115° shifts of the magnetic field. The two
half-circles indicate the 0.1% (broken line) and 5% (dotted line) significance
level according to the Rayleigh test
(Batschelet, 1981). The arrows
give the mean direction (
) and their length is proportional to the mean
vector length r with the radius of the circle=1. Outside of the circle
the 50% inter-quartile range (IQR) is indicated. Only included are those
studies that exposed the birds to sunset cues and where both control and
experimental groups exhibited significant unimodal orientation, with a
significant shift between treatments, and the control direction did not
coincide with the position of the setting sun
(Table 2A, studies not listed
in parentheses).
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