Pigeon Homing: New Experiments Involving Permanent-Resident Deflector-Loft Birds

Abstract

Experienced permanent-resident deflector-loft birds, when tested under sun, exhibit significant deflections of mean vanishing bearing as predicted by the olfactory theory. When released under total overcast at the same site, however, these same birds show a very much reduced deflection, suggesting that the sun is necessary for expression of the deflector-loft effect. When housed or raised in altered deflector lofts which rotate winds opposite to reflected light cues, the birds maintain olfactory expected deflections. Furthermore, deflector loft control birds, when housed for 10 and 13 days in regular and altered deflector lofts, respectively, exhibit deflections that are in agreement with the hypothesis that reflected light cues are the orientation parameter of importance in generating the deflector-loft phenomenon. At present, therefore, the involvement of light cues in the permanent-resident deflector-loft effect remains uncertain.