Pigeons' landmark use as revealed in a 'feature-positive', digitized landscape, touchscreen paradigm

Two pigeons were trained to discriminate between a S - (a digitized image of a grassy field presented on a computer monitor) and a S + (a digitized image of the same field containing a tree, a set of flowers, and a log). The location of the pecks to the images was recorded by a touchscreen. Both subjects quickly learned the discrimination and concentrated their pecks to particular 'landmarks', one pigeon pecking the flowers, the other the tree. This result suggests that the use of digitized images of real-world geographic locations may help us to understand how animals use visual landmarks in spatial navigation, and, in more general terms, how animals perceive and remember in their natural environments.