218 Transactions. 



entirely by trans-oceanic migration. The land avifauna and flora are 

 unmistakably closely allied to those of New Zealand, so that the islands 

 fall naturally within the New Zealand biological region. The marine 

 fauna has affinities with that of Polynesia. An explanation of this meet- 

 ing of New Zealand land species and Polynesian marine species may lie 

 in the fact that during the winter months, which cover the period when 

 plant-seeds are being dispersed, the prevailing winds in the Kermadecs 

 are from the south-west, while during the summer months, when the free- 

 swimming larval forms of marine animals are abundant, the prevailing 

 winds are from the north-east. 



The Lord Howe - Norfolk Inland Province and the Kermadec Islands 



Province. 



Having shown by an analysis of their avifaunas that Lord Howe, Nor- 

 folk, and the Kermadec Islands fall within the limits of the New Zealand 

 biological region, it remains only to consider whether they form one or 

 more provinces or subregions of that region. 



The avifaunas of Lord Howe and Norfolk Islands are undoubtedlv 

 closely allied. Of the resident land-birds two species are common, to 

 which must be added the endemic species of four genera — Gerygone, 

 Cyanorhamyhus, Turdus, Zosterops — having representative forms in each 

 island. Most of the sea -birds (breeding), migrants, and occasional 

 visitors are. common to the two islands, but, from the manner of their 

 occurrence, this is not the case with the accidental visitors and the sea- 

 birds (visitors). 



With regard to the six resident land-birds of the Kermadec Islands, all 

 except Prosthemadera novae-zealandiae are identical with or closely allied 

 to species in Norfolk Island or Lord Howe Island. But of resident land- 

 birds in Lord Howe or Norfolk Islands found also in the Kermadecs the 

 proportion is very low, so that the fact that five-sixths of the Kermadec 

 land-birds are related to species found in Lord Howe and Norfolk Islands 

 merely shows that in all probability, as Avith the plants, some of the species 

 in the Kermadecs which occur in both New Zealand and Norfolk Island 

 have arrived from Norfolk Island direct. The sea-birds (breeding) and 

 migrants chiefly belong to the same species as occur in Lord Howe and 

 Norfolk Islands. The occasional and accidental visitors, like the resident 

 land-birds, are very few, a fact which can be explained by the isolated 

 position of the islands. 



The three islands therefore fall naturally into two biological provinces. 

 One includes Lord Howe and Norfolk Islands, and is characterized by an 

 avifauna containing four main elements : (1) an original element which 

 includes the species which came by the ancient New Caledonia- New Zea- 

 land land bridge (majority of resident land-birds); (2) Australian and 

 New Zealand species arrived subsequently by trans -oceanic migration 

 (some of the resident land-birds and all the visitors except migrants); 

 (3) circumtropical species (sea-birds, breeding); (4) migrants. The Ker- 

 madec province contains only — (1) New Zealand (and Norfolk Island) 

 species arrived by trans -oceanic migration; (2) circumtropical species 

 (sea-birds, breeding); (3) migrants. Although the important and charac- 

 teristic element circumtropical species is common to the three islands, 

 and, in the case of plants, formed the basis of my subtropical islands 

 province,* I think now, on a consideration of the avifauna, that a more 



* Trans. N.Z. Inst., vol. 42, p. 155. 



