Pigeons' (Columba livia) encoding of geometric and featural properties of a spatial environment.

Pigeons (Columba livia) searched for hidden food in a rectangular environment constructed to eliminate xternal orientation cues. A feature group was initially trained with distinct features in each corner. A geometric group was initially trained with no featural information. Tests revealed that both groups encoded the geometry of the apparatus. The geometric group was then retrained with features, and a series of tests was administered to both groups. Transformation tests revealed that he groups differed in reliance on features versus geometry. Pigeons in the feature group followed the positive feature ven when it was placed in a geometrically incorrect orner, whereas pigeons in the geometric group showed shared control by features and geometry. Both groups were able to use features in corners distant to the goal to orient themselves, and both groups relied more on the color than on the shape of the features. Survival within an environment frequently requires effi-cient processing of spatial information. Spatial abilities underlie activities that are critical for the individual (e.g., establishment of lodging, avoidance of predation, and attain-