JUVENILE DISPERSAL BEHAVIOR AND NATAL PHILOPATRY OF A LONG-LIVED RAPTOR, THE SPANISH IMPERIAL EAGLE AQUILA-ADALBERTI

The dispersal behaviour of 30 radio-tagged young Spanish Imperial Eagles Aquila adalberti was studied in southwestern Spain in 1986-1990. The dispersal process involved first departure from the natal population, exploratory movements, temporary settlements and returns to the natal population. The dispersal process lasted for the whole of the immature period studied, and behaviour was radically different from that displayed by territorial adults. Movements between temporary settling areas and the natal population occurred continually throughout the dispersal period. Return to the natal population could be used by the young to explore the possibilities for pair formation where a vacancy may have occurred in the breeding population.