Avian vision.

The primary reliance of birds on vision is readily and frequently asserted. Casual observations of birds completing their everyday behaviours is sufficient to convince most observers that birds are using vision to control their key behaviours. This assertion is supported by evidence that in most bird species relatively large portions of their brains are devoted to the analysis of information from vision. Also, the so-called intelligent behaviours of birds seem to be based primarily upon visual information. Thus, gaining information from vision, and using it to guide sophisticated behaviours, is seen as a vital component of what makes birds so fascinating. Martin provides an overview of bird vision, its underlying physiology and anatomy, and the key factors that have driven its diversity. [ABSTRACT FROM AUTHOR]