Spatiotemporal programmes and genetics of orientation

Abstract

A number of migratory bird species have endogenous annual rhythms that regulate the entire annual cycle, including migration. Captive migrants display inherited migrational activity; this could theoretically also be used by free-living migrants as a time programme for migration. This heritable migrational activity is oriented in a seasonally appropriate direction, even in naive birds. These characteristics should enable inexperienced migrants isolated from contact with experiences conspecifics, to utilize a heritable vector-navigation programme to migrate from the breeding grounds to the winter quarters. The time course of migration, as established by trapping stations, theoretical influences of environmental variables on migration programmes, and also compensatory behaviour and backup measures, are discussed. A large number of migrants appear to be essentially brought to their wintering areas by vector-navigation systems. -from Author