THE DESTRUCTION OF SOURCE AND SINK HABITATS IN THE DECLINE OF THE MAURITIUS-FODY, FOUDIA-RUBRA, AN ISLAND-ENDEMIC BIRD

The population of the Mauritius Fody, Foudia rubra, a rare island-ende mic bird, was structured as five subpopulations. The largest comprised small source areas contiguous with larger sink areas. The remainder w ere relicts, left by habitat destruction, from a time when the distrib ution was far more extensive. No evidence was found for a classical me tapopulation structure. Destruction of source areas would have severe effects on population viability; their creation is the key to enhancin g it. Following habitat destruction (1950-1975), fodies unexpectedly d isappeared from habitat areas that were not destroyed; this probably o ccurred because the area destroyed contained source areas upon which a djacent, intact sink areas depended. The suggestion that introduced ne st predators are likely only to affect native animal populations soon after their arrival is strongly rejected.