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| Using a meta-analysis approach we re-analysed
orientation cage experiments with displaced migrants found
in the literature. A rather large proportion of the orientation
experiments showed directional shifts after displacements,
indicating ability for birds to detect and react on such
displacements. There was a clear difference between overcast
and experiments where birds had a view of the starry sky. In
experiments under a starry sky, the birds compensated the
displacements, whilst under overcast unaltered or reverse
orientations were generally displayed. This indicates a role for
the stars to be involved in detection of the changes in position.
Such a role of celestial cues is further stressed by the results of
several studies manipulating a planetarium sky. | |
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