FURTHER EVIDENCE FOR VISUAL LANDMARK INVOLVEMENT IN THE PIGEONS FAMILIAR AREA MAP

In previous experiments suggesting that previewing visual landscapes s peeds homing from familiar release sites, restricted access to olfacto ry cues may have artefactually encouraged homing pigeons, Calumba livi a, to resort to visual landmark orientation. Since evidence for the ro le of visual landmarks in wide-ranging avian orientation is still equi vocal, Braithwaite & Guilford's (1991, Proc. R. Sec. Lond. Ser. B, 245 , 183-186) 'previewing' experiments were replicated: birds were allowe d or denied visual access to a familiar site prior to release, but all owed ample access to olfactory cues. In experiment 1, allowing birds t o preview familiar sites for 5 min prior to release enhanced homing sp eeds by about 12%. In experiment 2, modified to reduce between-day eff ects on variation, previewing enhanced homing speeds by about 16%. The se experiments support the conclusion that visual landmarks remote fro m sight of the loft are an important component of the familiar area ma p, although the nature of the landmarks and how they are encoded remai n to be determined. (C) 1997 The Association for the Study of Animal B ehaviour.