Terrestrial birds of the Indo-Pacific 361 Terrestrial birds of the Indo-Pacific B Michaux Private Bag, Kaukapakapa, New Zealand Key words: Indo-Pacific biogeography, fragmentation of east Gondwana, nightjars, Gallirallus philippensis Abstract of the 265 species of land birds which are known from that part of New Guinea which is The avifaunas of New Zealand, New Caledonia, central Poly- opposite New Britain, only about 80 species nesia, New Guinea, Maluku and Sulawesi are discussed Dis- have a representative on New Britain In other tributional patterns within and between avifaunas are de- scribed and related to Mesozoic tectonic activity along the words, the 45 mile [70 km] stretch of water east Gondwana margin Spreading, rift formation, subduc- which separates the two islands has prevented tion, obduction and mobile arc systems were all important the crossing over of 70 percent of the New components of this activity Avian distributional patterns at Guinean species family, genus and species levels are discussed in terms of rift- arc interactions within modern zones of active plate conver- gence Clearly there is more to colonisation than cross- ing barriers because most birds should be able to cross 70 km of sea Yet according to Mayr Introduction only 30% of the Huon peninsula avifauna has shown evidence of colonising New Britain Mayr Im sure that Leon Croizat would have derived (1941) thought that 70% sedentary species was some satisfaction at this coming together of biol- general for avifaunas within the Indo-Australian ogists and geologists to discuss matters of mutu- archipelago Poor colonising ability and a devel- al interest regarding the Indo-Pacific region For oped taxonomic and systematic base make birds biologists the Indo-Pacific is an evolutionary excellent biogeographical tools laboratory in which taxonomic diversification The avifaunas of New Zealand, New Guinea, has occurred on a dynamic and complex stage Fiji, Tonga, Samoa, Maluku and Sulawesi are For geologists it is a region where a modern described and broad patterns in the distribu- orogeny can be studied and its development tional data discussed These patterns link Indo- through time reconstructed The key question Pacific islands into a number of groupings for me is to what extent are distributional pat- These groupings do not always follow conven- terns consistent with the reconstructions provid- tion, for example Timor is linked to south ed by geologists? Maluku Island groupings based on avifaunal Even though most birds are highly mobile, a distributions are related to three broad geologi- component of an islands avifauna is sedentary cal systems These are the Melanesian rift-arc What proportion of an avifauna is sedentary de- system, the Banda rift-arc system and the Sumba pends on several factors, including distance to ar- terrane The geological histories of these struc- eas that could be colonised Mayr (1941) dis- tures are described and differences in geological cussed the efficiency of sea barriers to bird coloni- interpretations discussed sation from New Guinea to New Britain and said: Finally, distributional patterns are interpreted Biogeography and Geological Evolution of SE Asia, pp 361-391 Edited by Robert Hall and Jeremy D Holloway © 1998 Backhuys Publishers, Leiden, The Netherlands 362 B Michaux in the light of geologists reconstructions These islands such as New Caledonia, Vanuatu, the interpretations are necessarily general for two Solomon Islands, Fiji, Samoa and Tonga, or In- reasons Firstly, cladistic bird phylogenies of ap- donesia The genera Nestor and Cyanoramphus propriate scope are not available In most cases (Psittacidae) and the species Eudynamis the taxa used in describing patterns are either taitensis (Cuculidae) are endemic to the south- species or genera for which monophyly is likely, west Pacific but as yet undemonstrated cladistically How- Low diversity at family, generic and (with few ever, Sibley and Ahlquist (1990) have produced exceptions) specific levels is also a characteristic a systematic treatment which is used to examine of the New Zealand terrestrial bird fauna While the relationship between nightjar evolution and it is true that extinction has reduced taxonomic the Mesozoic and Tertiary history of the Indo- diversity (the families Dinornithidae, Emeidae, Pacific in some detail The second reason is that Pelagornithidae, Pelecanidae, Phasianidae, Ap- the geology of the Indo-Pacific is complicated tornithidae, Aegothelidae, Turnagridae and Cor- and many geological questions are yet to be re- vidae are no longer part of New Zealands en- solved Definitive answers to problems of Indo- demic fauna), it would seem that low diversity Pacific biogeography are not available at has always been a characteristic of New Zea- present, but this is precisely what makes the lands terrestrial avifauna Bird families that one Indo-Pacific such an interesting area for re- might have expected to be part of New Zea- search lands pre-European avifauna are missing For example, some self- or deliberately introduced members of the families Cracticidae (Australian Avifaunas Magpie), Hirundinidae (Welcome Swallow) and Turdidae (Blackbird and Song Thrush) have es- New Zealand tablished themselves in New Zealand Within families there is a general paucity of Extant and extinct New Zealand (Fig1: 1) terres- genera and species This point is illustrated by trial birds are listed in Table 1 The data came the family Columbidae which is represented in from Falla et al (1979), Fordyce (1982), Fuller New Zealand by a single species Hemiphaga (1987) and Turbott (1990) Species unknown to novaeseelandiae The genus Hemiphaga is now pre-European Maori (i e, lack a Maori name) confined to New Zealand, but an extinct sub- and self-introduced since European arrival are species, H novaeseelandiae spadicae, was not included in Table 1, because many of these found on Norfolk Island (Schodde et al , 1983) species appear to be associated with man-made This can be contrasted with the Columbidae in habitats The presence of these species may be New Caledonia, where there are six species in due to the availability of grassland habitats, in- five genera, or in Australia where there are 23 troduced food sources or nesting sites, and they species in eleven genera The exceptions to this have been excluded Table 1 shows two charac- pattern are the Anatidae, Rallidae and Phalacro- teristics of New Zealands terrestrial avifauna, a coracidae This latter family reaches its greatest high degree of endemism and low taxonomic specific diversity in New Zealand waters Cor- diversity morants have been included in this study be- Five endemic terrestrial avian families are cause four species (Phalacrocorax carbo, P sul- listed in Table 1 The Apterygidae (kiwi), cirostris, P melanoleucos, and P varius) are Acanthisittidae (New Zealand wrens) and predominantly estuarine or freshwater, but oth- Callaeatidae (New Zealand wattle birds, includ- er members of the family are marine or oceanic ing the extinct huia) are extant, while two fami- species lies of moa, the Emeidae and Dinornithidae, are extinct New Zealand thrushes were represented by a single extinct species the piopio re- New Caledonia garded by Turbott (1990) as a member of the Paradisaeidae, but better placed either in the The terrestrial avifauna of New Caledonia (Fig1: Turnagridae or Ptilonorhynchidae (Sibley, pers 2) and the Loyalty Islands is listed in Table 2 comm, 1996) Thirty five genera and 79 species The data for Table 2 are from Mayr (1945) Table listed in Table 1 are endemic Only seven spe- 2 shows that the number of avian taxa endemic cies are shared with Australia and three of these in New Caledonia is less than in New Zealand are also found elsewhere A further twenty spe- There are five endemic genera (Keast (1996) cies are shared with Australia, southwest Pacific records eight), 21 endemic species and a single Terrestrial birds of the Indo-Pacific 363 Fig 1 The Indo-Pacific region showing extent of continental crust and marginal oceanic basins (stippled) Avifaunas discussed in text: 1 = New Zealand, 2 = New Caledonia, 3 = Fiji, Tonga and Samoa, 4 = New Guinea, 5 = Maluku, 6 = Sulawesi Marginal basins: AS = Andaman Sea, sBS = south Banda Sea, CS = Coral Sea, CeS = Celebes Sea, sCSB = South China Sea, M = Makassar Strait, MB = Manus Basin, NC = New Caledonian Basin, NFB = North Fiji Basin, PO = SW Pacific, SB = Sulu Basin, SCB = Santa Cruz and Loyalty Basins, SFB = south Fiji Basin, SS = Solomon Sea, TS = Tasman Sea CP = Campbell Plateau, CR = Chatham Rise, LHR = Lord Howe Rise, NR = Norfolk Ridge, OJP = Ontong Java Plateau, IO = Indian Ocean Bo = Borneo, F = Fiji, nI = North Island, New Zealand, sI = South Island, New Zealand, J = Java, NG = New Guinea, S = Samoa, So = Solomons, T = Tonga, V = Vanuatu endemic family the Rhynochetidae in New tralian avifauna Caledonia The number of endemic taxa has Within the non-endemic element of New Cal- been greater in the past Balouet and Olson edonias avifauna, distributional patterns are (1989) describe a large, flightless species similar to those discussed for New Zealand Sylviornis neocaledonica (Megapodiidae?) from Only three species are shared exclusively with Holocene deposits, together with eleven extinct Australia despite New Caledonias proximity to non-passerine species that have relatives on the Australian continent Thirty three species smaller islands off New Zealand, northern Mela- (44% of the total avifauna) have widespread dis- nesia and Asia Two extinct