Lateralization of Spatial Orientation in Birds
Research on the specific role of the left and the right brain hemispheres during spatial orientation in birds is of great interest for several reasons. After it has become clear that lateralization is not restricted to humans, but is evolutionarily old and widespread among vertebrates, birds have established as one o f the most important research models in this area. Furthermore, for a long time birds have been a major model in the study of spatial orientation in animals. In addition to behavior they share with vertebrates from other classes, they exhibit specific feats related to the fact that many species migrate and home over large distances. A number of recent studies show that, contrary to classical theory, spatial orientation in birds is not a mainly right-hemispheric task. It requires full involvement of either hemisphere, and several of the major orientation mechanisms are predominandy based in the left; brain. During visual landmark orientation, both the left and right brain are essential, and they may contrib ute different aspects of spatial information. Mechanisms concerned with directional orienta tion strongly rely on the left brain hemisphere as olfactory orientation sun-compass based orientation and magnetic compass orientation. Comparative studies suggest a similar basic pattern of lateralization across species o f different avian orders. However, along with different ecological niches this basic setup varies across species, leading to species-specific lateralization patterns for complex spatial behaviors.