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Summary.

  • 1
     Of the numerous European passerines (of British origin) liberated in New Zealand and Australia, mainly between the years 1860–1870, 13 are now established in New Zealand proper (North, South and Stewart Islands) and 8 in Australia (including Tasmania).
  • 2
     Within 30 to 40 years of their liberation many of these established species began to appear on the small islands in Australasian seas that (with one exception) lie between 200 and 550 miles from the main land masses.
  • 3
     Although it is known that in a few cases introductions were made by man, it seems likely that in most cases the birds were self-introduced.
  • 4
     The number of European species breeding on any one island varies from 1 in the case of Macquarie Island, which has the severest climate and the smallest variety of habitat types, to 10–r perhaps 11–n Chatham Island.
  • 5
     Dispersal seems to have been brought about by the birds being carried by the strong winds of these latitudes, and New Zealand appears to have been the main centre for this dispersal.
  • 6
     It is suggested that the chances of establishment on any one island have been governed by the potential frequency of arrival and the number of empty ecological niches in the new habitat. With such a poor native passerine avifauna as exists in the Kew Zealand region, empty ecological niches are apparently many.
  • 7
     There is no evidence that competition between indigenous and foreign passerines has occurred within New Zealand itself or on the offshore islands.
  • 8
     The Starling has the most widespread distribution—having appeared on all 9 islands and being known to breed on at least 7. The least “ successful” species appear to be the Dunnock, Skylark and Yellowhammer.