The ability of certain animals to navigate by instinct to specific sites, apparently without using any landmarks. Examples are salmon returning to the same rivers where they were born, birds returning to the same nesting sites after annual migrations, or Florida green tortoises finding the same beaches upon which to lay their eggs.

From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.