| Summary: | A vertebrate brain must acquire, store, and process vast amounts of information. For birds, the majority of the incoming sensory information is visual, and like all vertebrates - except eutherian mammals - their visual system is bifurcated, with each eye feeding incoming information to the contralateral brain hemisphere. As a result, the bird must integrate these two banks of information to produce unified responses. This arrangement raises several questions about how a bird acquires, manages, and represents incoming visual information, and this thesis explores three of these questions. First, two studies investigate information integration across the two brain hemispheres in a long-term and short-term assay of birds trained monocularly with one eye and then tested with the other. The first finds that over a long term learning task in pigeons, some interhemispheric transfer of learned information occurs, but that complete integration does not occur. The second, using imprinting in ducklings, shows that the eye occluded during training has no demonstrable access to the learned information for at least three hours. A third study demonstrates that New Caledonian crows hold tools laterally in order to prioritize visual contact with the tool by their dominant eye during foraging, offering a potential underlying cause of this previously unexplained behavioural laterality. The fourth study explores the nature of information itself in the avian brain, showing that the maternal imprint formed by a newly hatched duckling can include abstract concepts defining the maternal stimulus, rather than just memory for visual images. This extends relational concept learning to a new species and suggests a much broader phylogenetic distribution of this ability. Combined, the studies suggest that the avian brain coordinates action managing two somewhat independent banks of information, biasing body positions in monocular tasks to allow control by a preferred eye, and has hitherto unsuspected capacity for abstract concept formation.
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