An ornithological survey of Vanuatu on the islands of Éfaté , Malakula , Gaua , and Vanua Lava

We surveyed forest birds on 4 islands in Vanuatu from November–December 2014, including sites on Éfaté, Malakula, Gaua, and Vanua Lava Islands. Here, we summarize our survey results and place them into the context of prior ornithological surveys in Vanuatu. We recorded 44 species across all survey sites, including eight species endemic to Vanuatu and another 6 species endemic to the region of Southern Melanesia. We collected voucher specimens of 26 species and made 98 recordings of vocalizations from 24 species. Malakula was the most diverse site we surveyed with 35 native species. We observed differences in breeding phenology across islands and between species within survey sites. There was more evidence of breeding by birds on Éfaté and Malakula than on Gaua and Vanua Lava. Finally, we present local bird names from each surveyed site as described by village elders and local guides.


Introduction
Vanuatu is an oceanic island archipelago in Southern Melanesia that comprises more than 80 volcanic islands (Fig. 1).Oriented along the New Hebrides Arc, Vanuatu is positioned southeast of the Solomon Islands (1,290 km between capital cities, Honiara and Vila), about 500 km northeast of New Caledonia, and about 1,000 km west of Fiji.The New Hebrides Arc comprises all of Vanuatu plus Temotu Province, Solomon Islands, which is only 150-250 km north of Vanuatu's Torres Islands.Santo is Vanuatu's largest island (3,955 km 2 ) and 13 additional islands are greater than 100 km 2 (Nunn 1994).
The geologic history of Vanuatu is defined by three "belts" of islands representing different periods of orogeny (Mitchell and Warden 1971, Greene et al. 1988a, 1988b, Macfarlane 1988).The Western Belt includes Malakula and Santo Islands, whereas the Eastern Belt encompasses Maweo and Pentecost Islands.The Central Belt comprises the majority of islands from Temotu Province in the Solomon Islands south to Aneityum Island, Vanuatu.Beyond Aneityum, two small islands, Matthew and Hunter, form the southern terminus of the Central Belt.The oldest rocks in Vanuatu date from the Miocene ANNOTATED LIST OF SPECIES and occur in the Western and Eastern Belts (Macfarlane 1988).The Central Belt remains volcanically active and is composed of much younger rocks that range from modern to the Pliocene.The majority of Vanuatu's islands (e.g., those within the Central Belt) became subaerial 2-6 million years ago (Ma), but Santo and Malakula were subaerial more than 10 Ma (Greene et al. 1994).
The New Hebrides Arc is characterized by lowland and montane humid forest.Some islands have extensive closed-canopy coniferous forests (e.g., Santo, Erromango, and Aneityum) and cloud forest exists on Santo.Extensive mangrove forests occur on several islands, such as Malakula.Lowland forest throughout Vanuatu is under threat from local subsistence farming, slash-andburn agriculture, and cattle grazing.Together, islands of the New Hebrides Arc comprise the Vanuatu and Temotu Endemic Bird Area (Stattersfield et al. 1998).There are 15 restricted-range species confined to this endemic bird area (EBA), with an additional 15 species present in other nearby EBAs (e.g., Solomon Group, New Caledonia, and Fiji).All restricted-range species are forest birds, thus, forest conservation in the New Hebrides Arc is a high priority for longevity of these species' populations.
There have been several ornithological inventories of Vanuatu.Tristram reported on collections from Vanuatu (New Hebrides) in the 1870s (Tristram 1876(Tristram , 1879) ) and the American Museum of Natural History (AMNH) has small collections from the 1870s and 1899-1901 by an unknown collector from the Rothschild collection (P.Sweet, pers. comm.).Additional small collections exist at AMNH from the Senckenburg Museum dating to the 1960s (P.Sweet, pers.comm.) and the Museum of Vertebrate Zoology at UC Berkeley collected in 1943-1944 by T. E. Reynolds and C. G. Sibley.The largest collection of Vanuatu birds-also curated at AMNH-is from the Whitney South Sea Expedition (WSSE;Murphy 1922;Chapman 1935;Bryan Jr. 1969).The WSSE conducted major ornithological expeditions in the archipelago, led by Rollo Beck from June 1926-January 1927 (Beck 1969).Beck was accompanied first by José G. Correia until 9 December 1926 and later by Frederick P. Drowne on 13 January 1927, just days before they left Vanuatu for the Solomon Islands (Correia 1969;Drowne 1969).The WSSE did not collect south of Éfaté, except for their first 6 days in Vanuatu after arriving from New Zealand.From 1935-1937, just after the WSSE concluded, Lindsay T. Macmillan collected specimens on Tanna, Erromango, and Aneityum (Bryan Jr. 1969); these specimens represent the only major collection of birds from the southern islands and are also housed at the AMNH.
Much of what we know about the status and distribution of Vanuatu's avifauna can be traced to these collections.Ernst Mayr published extensively on the systematics and distribution of Melanesian birds, with numerous contributions focusing on the birds of Vanuatu (e.g., Mayr 1931Mayr , 1932aMayr , 1932bMayr , 1933Mayr , 1938Mayr , 1941)).He synthesized this work with respect to the origin and biogeography of the Polynesian avifauna (Mayr 1940a(Mayr , 1940b) ) and in a book that became the first field guide to the birds of the southwest Pacific (Mayr 1945).The Royal Society/Percy Sladen Expedition surveyed eleven sites on 6 islands in Vanuatu (Santo, Malakula, Éfaté, Erromango, Tanna, and Aneityum) with a focus on all terrestrial vertebrates (Medway and Marshall 1975).They surveyed birds with mist nets, but did not collect bird specimens.Their "observations confirmed the general picture of Mayr's (1945) summary, and neither added to the species nor extended the known dates of their [WSSE] sojourn in the New Hebrides" (Medway and Marshall 1975:430).Bregulla (1992) later wrote a comprehensive book on the status and distribution of the birds of Vanuatu, and recently, a modern field guide to the birds of Melanesia-including Vanuatu-was written by Dutson (2011).
There have been several recent museum-based ornithological surveys in Vanuatu covering Santo (Kratter et al. 2006), as well as Éfaté, and Tanna (J.Kirchman, pers.comm.), which provided the first genetic samples from the archipelago and invaluable comparative material from those islands.However, the specimens collected by the WSSE remain the only comparative material from most islands in Vanuatu, with only minimal resurvey effort since WSSE.Few recordings exist of bird vocalizations of Vanuatu birds.Prior to our work, a combined total of 63 recordings were archived in the Macaulay Library and Xeno-canto.Additional audio material was recorded during bird surveys of Santo by Jennifer Bowen (Bowen 1997) and Andrew Kratter (Kratter et al. 2006) and are deposited in the British Library Sound Archive and the Florida Museum of Natural History Sound Archives, respectively.The relative paucity of rich media of Vanuatu birds is in stark contrast to nearby archipelagos like the Solomon Islands and Fiji, which have 1,068 and 648 archived recordings, respectively.
We surveyed select islands in Vanuatu to compile contemporary species lists and to collect modern comparative material.Here, we report results of an avifaunal survey of 4 islands in Vanuatu: Éfaté, Malakula, Gaua, and Vanua Lava.We surveyed birds by mist net captures, recording vocalizations, and passive observations, and we prepared museum voucher specimens and collected genetic samples for use in ongoing comparative projects.We compare our results to previous survey work in the archipelago and discuss relative abundance and evidence of breeding, including observed patterns of interisland differences in breeding phenology.

Study sites
Éfaté Island, Shéfa Province.We established a camp on the border of Tukutuku Ranch, 4.2 km southeast of Port Havana on the northwest side of Éfaté (17.6029° S, 168.2827° E, 325 m elevation).[All coordinates in this paper are reported in WGS84.]We surveyed mature secondary forest with closed canopy (20-25 m high) and forest edge in dense shrubby vegetation among small patches of secondary forest from 18-21 November 2014.We cut a trail to access forested habitat from camp and we walked an existing jeep track 0.5 km south of camp that gave us access to similar secondary forest habitat.The forest understory was relatively open and easy to walk through at this site.Total mist net effort was 670.8 net-hours or 167.7 net-hours per day.Weather was generally moderate throughout our time with daytime high temperatures 25-28°C and nighttime lows 18-20°C; skies were mostly clear to partly cloudy with one brief rain shower on 18 November.Winds were calm 17-19 November, but breezy 20-21 November.Weather at this site never impeded our survey effort.
Malakula Island, Malampa Province.We established a camp along a dirt road 5.2 km southwest of Lingarak Village (16.2134° S, 167.4356°E, 100 m elevation) from 25-30 November 2014.We surveyed mature primary forest along two trails: a ridge trail above camp to approximately 330 m, and west along an overgrown jeep road from camp for 1.5 km.Understory vegetation throughout this tall primary forest (25 m canopy) was relatively open and easy to walk through.We also surveyed edge and garden habitats near camp, and a riparian forest with a flowing stream.Total mist net effort was 632.6 nethours or 126.5 net-hours per day.Weather was generally hot during the day, with daytime highs approaching 30°C and lows near 20°C; skies were clear with no precipitation and winds were calm.Weather at this site never impeded on our survey effort.
Gaua Island, Torba Province.We established a camp on the east shore of Lake Letes (14.2747° S, 167.5488°E, 400 m elevation) from 3-6 December 2014.Lake Letes is 1 of approximately 25 freshwater lakes in Vanuatu, and the largest in the Southwest Pacific outside New Guinea, Australia, and New Zealand (Bregulla 1992).We surveyed premontane primary forest along a trail from the lakeshore to the old crater rim east of camp (470 m).The forest was closed canopy, but stunted compared to lowland forest nearer the coast.Canopy height was 15-20 m with 25-meter emergent canopy trees.The understory was dense with tree ferns and other woody vegetation.
Most trees had at least some wet moss covering their trunks.Total mist net effort was 437.7 net-hours or 109.4 net-hours per day.We spent our last morning exploring the southeast slope of Mt.Gharat (spelled Garet on some maps), the active volcano on the west side of Lake Letes, but we did not collect or record bird songs there.Daytime high temperatures at our Lake Letes camp were approximately 18-20°C.A low cloud ceiling was trapped over Lake Letes with frequent rain showers that were heavy at times.The heaviest rain slowed our survey efforts for 1-3 hours each day.
Vanua Lava Island, Torba Province.We established a camp on a steep ridge trail 1.3 km northeast of Mosina Village in the southeast part of the island (13.8876° S, 167.5287°E, 350 m elevation).According to local villagers, our camp was the site of a Second World War, US military camp from 1942-1945.We surveyed premontane primary forest between 350-500 m from 9-11 December 2014.The forest canopy here was 15-20 m at camp, but shorter (12-15 m) on the ridge above camps at 500 m.The forest understory was fairly dense; more than the forests we surveyed on Éfaté and Malakula, but less than Gaua.Total mist net effort was 506.3 net-hours or 168.8 net-hours per day.Weather was moderate throughout our survey on Vanua Lava.The low pressure system that affected our work on Gaua cleared out and left clear skies with daytime high temperatures in the low 20s°C with light winds.Data collection.We documented occurrences of upland forest bird species with voucher specimens, audio recordings, mist net captures, and observations at 4 sites on Éfaté, Malakula (spelled Malekula on some maps), Gaua, and Vanua Lava, Vanuatu (Fig. 1).Our mist net effort included 16-21 12-m mist nets that we opened from 05:00 h to 17:00 h daily, occasionally as early as 04:30 h and as late as 18:15 h (Table 1).We provide total and average daily mist net hours from each camp below.We focused mist net effort in primary forest, with fewer nets placed in edge or garden habitats with open canopy.Daily observations were made by the entire team and MJA recorded bird vocalizations using a Nagra ARES-BB+ digital audio recorder with a Telinga Pro6 stereo parabola.
We prepared specimens as dried round skins, spreadwings, complete or partial skeletons, and/or preserved whole in 10% formaldehyde.We preserved pectoral muscle tissue in 2 cryo-tubes, the first in liquid nitrogen, the second in 95% ethanol.We noted detailed information on each specimen, including collection date and locality, weight, sex and measurement of gonads, presence and measurement of bursa of Fabricius as a proxy for age (Glick et al. 1956), skull ossification, stomach and crop contents, fat condition, coloration of soft parts (e.g., iris, facial skin, bill, mouth lining, tarsus, and feet), and molt condition.These data are noted on specimen labels and are accessible via the AMNH Ornithology Department.We noted breeding evidence from specimens if females had yolking eggs, convoluted oviducts, or a brood patch and if males had enlarged testes or enlarged seminal vesicles.Behavioral evidence of breeding included male territorial vocalizations, adults seen feeding young, and active nests.We collected specimens under Scientific Collecting Permit No. ENV 314/014/2014/LF/tt administered by the Vanuatu Department of Environment and Conservation.
We deposited specimens at the American Museum of Natural History, New York, NY, USA, and in the Vanuatu Cultural Center, Port Vila, Vanuatu.Audio recordings are archived at the Macaulay Library, Cornell Laboratory of Ornithology, Ithaca, NY, USA and are available online (advanced search: Country: Vanuatu, Recordist: Michael J. Andersen; http://www.macaulaylibrary.org).Observational data are archived on eBird (http://www.ebird.org)and are available to download through the Avian Knowledge Network (http://www.avianknowledge.net).Taxonomy and nomenclature follows (Clements et al.

2016
). Species identifications were made in the field using Dutson (2011) and verified using comparative material at the American Museum of Natural History, New York in consultation with P. Sweet.

Results
We documented 44 species of birds during our surveys (Table 2).Forty-one species are native and three are nonnative (Red Junglefowl Gallus gallus, Common Myna Acridotheres tristis, and Common Waxbill Estrilda astrild); an additional three non-native species were observed in transit between survey sites and are discussed below.We observed an additional 8 species (5 native, 3 non-native) outside of our survey sites (see Table 2 footnotes for details).Site-specific diversity was highest on Malakula (N = 35 native species + 1 non-native), followed by Éfaté (N = 28 native species + 3 non-native), then Vanua Lava (N = 27 native species), and Gaua (N = 26 native species).We prepared vouchered specimens at all 4 survey sites, including study skins, skeletons, and fluid-preserved anatomical specimens, all with associated genetic samples (Table A1).Site-specific numbers of collected species are as follows: Malakula (21 species); Éfaté (15 species); Vanua Lava (15 species); and Gaua (13 species).We archived 98 recordings of bird vocalizations from 28 species across all islands (Table A2).An additional 2 recordings remain unidentified (ML 515718, ML 515787); please contact MJA or the Macaulay Library if you can help identify them.
We discussed our survey results with village elders and guides, who in turn, provided local names for many bird species (Table A3).Discussion about local bird names involved examination of field guides with villagers, walking trails and bird-watching with local guides, and inspection of birds and specimens in the hand.The language of Lingarak Village, Malakula Island is Neverver; other language names were not noted.

Annotated list
We present an annotated list of select species including notes on systematics; relative abundance; breeding, molt, and diet; and the IUCN Red List conservation status (IUCN 2016).Taxonomy and nomenclature follows The eBird/Clements Checklist of Birds of the World (Clements et al. 2016).Identification of forest birds in Vanuatu generally is straitforward because most genera only have 1 representative in the entire country.Nevertheless, we discuss briefly the salient features used in field identification.We referenced Dutson (2011) in the field and comparative material in the American Museum of Natural History ornithology collection to help with identifications.Tristram, 1879, Vanuatu Scrubfowl We detected the endemic Vanuatu Scrubfowl only on Malakula Island in forest surrounding our camp.We heard them vocalizing on most days in the morning, and at least once an individual sang at night.MJA saw them once and made 2 recordings (Table A2).We identified Vanuatu Scrubfowl based on a slate-gray bird about the size and shape of a chicken, with a short tail and crest, red face, and stout yellow legs.Our guides showed us two eggs from an active nest mound near Lingarak Village, suggesting there is at least some egg-collecting pressure by villagers on Malakula.Egg harvesting-one of the most pressing influences on scrubfowl populations-is a concern elsewhere in Vanuatu (Bowen 1996, Foster 1999) where its IUCN status is Vulnerable.

Chalcophaps longirostris sandwichensis
The endemic Baker's Imperial-Pigeon is known from Santo Island and the Banks Group (Dutson 2011).We encountered this species in pre-montane primary forest near our camps on Gaua and Vanua Lava Islands.It was easily identified as a Ducula imperial-pigeon based on its large size.The plum-colored breast, chestnut underparts, and dark-gray upperparts were field marks used to identify this species from Pacific Imperial-Pigeon Ducula pacifica.The latter taxon was only observed in lowlands on Gaua and Vanua Lava, whereas we only saw D. bakeri at higher elevations.Birds on Gaua were difficult to detect because they were either scarce or not vocalizing Table 2. Relative abundance of bird species recorded during our survey of Éfaté, Malakula, Gaua, and Vanua Lava Islands, Vanuatu.Relative abundances are listed for each island: common (C), observed numerous instances daily, usually less than 3 individuals; fairly common (F), observed almost daily or daily; uncommon (U), observed regularly, but only once every few (2-3) days; and rare/scarce (R), observed only a few times or less during survey effort.Species documented with voice recordings are marked with "v" (see Table A2) and those for which voucher specimens were collected are marked with " †" (see Table A1).Six non-native species are listed (Red Junglefowl, Rock Pigeon, Common Myna, House Sparrow, Common Waxbill, and Chestnut Munia), but note they are not counted in diversity metrics in the text.Species marked "*" were recorded from that island, but away from the survey site and are not counted in diversity metrics in the text.Details about these records are annotated with footnotes.Species marked "-" were not recorded.Taxonomy follows (Clements et al. 2016)   frequently.Conversely, birds on Vanua Lava were vocalizing, which made detection easier.Kratter et al. (2006) experienced similar ease of detection of vocalizing birds at about 600 m elevation on Santo.Its IUCN status is Vulnerable.
Vanuatu Kingfisher is 1 of 2 Todiramphus kingfishers on Malakula where it is sympatric with Pacific Kingfisher, Todiramphus sacer (Dutson 2011).This is one of only a few examples of sympatric Todiramphus kingfisher pairs anywhere in the Pacific (Andersen et al. 2015).Prevailing wisdom suggests these sympatric species segregate by habitat, whereby one is more likely to be found in the island's interior and the other occupies edge or coastal habitat (Bregulla 1992, Pratt andEtpison 2008); however, we observed both Vanuatu Kingfisher and Pacific Kingfisher Todiramphus sacer occurring together in and around our Malakula camp.These species were easy to separate because T. farquhari has rich rufous-orange underparts and navy blue upperparts with a white collar, compared to whitish underparts and sea blue-green upperparts of T. sacer.(Gmelin, 1788), Pacific Kingfisher:

Todiramphus sacer
Pacific Kingfisher is a widespread species from the eastern Solomon Islands to Samoa and Tonga.It was recently recognized as a species separate from the polytypic Collared Kingfisher, Todiramphus chloris com-plex (Andersen et al. 2015).Twenty-two subspecies are described, of which 5 occur in Vanuatu (Clements et al. 2016).Our survey recorded 2 subspecies: juliae on Éfaté (Fig. 2C) and Malakula (Fig. 2D) and santoensis on Gaua and Vanua Lava.All T. sacer have whitish underparts and blue-green upperparts, making identification easy; however, plumage is variable between subspecies so our subspecific identifications were based on known allopatric distributions on specific islands.Pacific Kingfisher was common throughout and they occurred from the coastal scrub to interior forest, including in villages.Its IUCN status is Least Concern.MJA observed 1 individual leaving a nest cavity in a rotting log near our camp on Éfaté, 21 November 2014.Numerous specimens of T. s. juliae had enlarged gonads, but gonads on T. s. santoensis specimens showed no signs of breeding.Minimal molt was noted in these specimens and stomach contents included large arthropods, plus 1 individual from Éfaté with lizard bones.

Falconidae
Falco peregrinus Tunstall, 1771, Peregrine Falcon Psittaculidae Charmosyna palmarum (Gmelin, 1788), Palm Lorikeet: Figure 2E The Palm Lorikeet is endemic to Vanuatu and Temotu Province, Solomon Islands.We recorded this species only on Gaua Island, where it was fairly common.We noted it flying through camp daily and we observed small flocks (2-6 birds) foraging in a flowering palm near camp.Only 2 lorikeet species are known from Vanuatu: Charmosyna palmarum and Rainbow Lorikeet (Trichoglossus haematodus).The Charmosyna is easily identified by its smaller size and entirely green plumage, which makes it unmistakable from the sympatric and multicolored T. haematodus.Furthermore, its vocalizations are higherpitched and less full-bodied compared to, which made them readily identifiable by voice.Palm Lorikeet is a nomadic species that undergoes population fluctuations (Medway andMarshall 1975, Bregulla 1992).Apparently, it is now most regularly seen in the Banks Group (Dutson 2011), which fits the pattern of our only sightings on Gaua.Its IUCN status is Vulnerable.Four specimens exhibited light body molt, heavy fat loads, and stomach contents of flower parts.(Linnaeus, 1771), Rainbow Lorikeet Meliphagidae Myzomela cardinalis (Gmelin, 1788), Cardinal Myzomela: Figure 2F Gliciphila notabilis (Sharpe, 1899), Vanuatu Honeyeater: Figure 2G, H The Vanuatu Honeyeater is endemic to northern Vanuatu, from Epi north to Ureparapara Island in the Banks Group.This species has 2 described subspecies (notabilis in the north, superciliaris in the south; Dutson 2011).We observed it as fairly common only in large tracts of forest on Malakula (superciliaris; Fig. 2G) and Vanua Lava (notabilis; Fig. 2H), where it congregated in small groups of 3-10 birds in flowering trees.This observation was particularly evident on Vanua Lava where flocks were gregarious and noisy at dawn and dusk.Kratter et al. (2006) observed similar behavior on Santo Island.Gliciphila notabilis is the largest of 3 honeyeater (Meliphagidae) species in Vanuatu.It is a medium-sized, brown-and-white passerine with a salt-and-peppered face and decurved black bill.Its IUCN status is Least Concern.Of 3 specimens of notabilis, 2 had moderate to heavy fat loads and exhibited wing and body molt.All 3 had stomach contents of insects.One female had a convoluted oviduct, but with small follicles on 10 December 2014; others showed no signs of breeding evidence.

Trichoglossus haematodus massena
Curiously, Vanuatu Honeyeater is not known from Gaua Island, but MJA heard 1 bird on 4 December 2014 believed to be this species.It was vocalizing on the east shore of Lake Letes in pre-montane primary forest.Unfortunately, it was not seen and no concrete evidence was garnered; thus, we treat this record as provisional.(Latham, 1790), Darkbrown Honeyeater: Figure 3A Acanthizidae Gerygone flavolateralis (Gray, 1859), Fan-tailed Gerygone: Figure 3B Artamidae Artamus leucorhynchus (Linnaeus, 1771), Whitebeasted Woodswallow Campephagidae Coracina caledonica (Gmelin, 1788), South Melanesian Cuckooshrike Lalage maculosa (Peale, 1848), Polynesian Triller Lalage leucopyga (Gould, 1838), Long-tailed Triller Pachycephalidae Pachycephala chlorura intacta Gray, 1860, Vanuatu [Melanesian] Whistler: Figure 3C-D The polytypic Vanuatu Whistler (Fig. 3C, D) was common at our Éfaté and Malakula sites and uncommon at both of our Banks Group sites.Vanuatu Whistlers are easily identifiable based on their bright yellow underparts with a white throat delinated by a black collar and head.Superficially, they are similarly patterned to Neolalage banksiana; but the latter has extensive white in the tail, rump, and wings, whereas whistlers are uniformly dark green on the back.Female whistlers are muted versions of males with olive-brown backs, dull yellow underparts and a dingy white throat.Whistlers have characteristic loud vocalizations that make them easy to detect when singing.Birds on Éfaté and Malakula were singing vociferously, but were quiet on Gaua and Vanua Lava, making them more difficult to detect.Several lines of breeding evidence were noted on Éfaté and Malakula, including a female on Éfaté observed feeding a recently fledged young (21 November 2014), multiple male specimens with enlarged testes and seminal vesicles and females with convoluted oviducts, and singing males.Only 1 specimen showed signs of molt (Malakula).Conversely, specimens from Gaua and Vanua Lava were largely not in breeding condition and most were in body, wing, and tail molt.Stomach contents of all specimens were invariably of arthropods.

Lichmera incana griseoviridis
The Vanuatu Whistler has 4 subspecies (Clements et al. 2016).All our surveys were within the distribution of P. c. intacta, whereas 3 others occur in the south (chlorura on Erromango, cucullata on Anytiem, and littayei on the Loyalty Islands, New Caledonia).The taxonomic assignment of these 4 subspecies to Vanuatu Whistler is equivocal and may represent multiple species (Jønsson et al. 2014).Its IUCN status is Least Concern.Further survey work should focus on the southern subspecies so that these are represented in global tissue collections.

Rhipiduridae
Rhipidura verreauxi spilodera Marie, 1870, Streaked Fantail: Figure 3E Streaked Fantail was one of the most common and widespread understory forest birds we observed (Fig. 3E).It was the most frequently captured bird in mist nests on all 4 islands we surveyed.Indeed, it was common throughout and its IUCN status is Least Concern.It is a small, brownish passerine with a long, broadly fanned tail.Underparts are paler with bold, blurry streaking on the breast, separated by a white throat.Its face is black accented by white loral and post-ocular stripes.Its only congener in Vanuatu, Gray Fantail (R. albiscapa) has yellow underparts with a broad black breast band.These 2 species segregated by habitat preference: R. verreauxi was found exclusively in forest, whereas R. albiscapa was in forest edge, second growth, and villages.Streaked Fantail was a highly vocal component of the dawn chorus with its high-pitched, whistled song.Multiple male specimens throughout the survey had enlarged testes and seminal vesicles and females had convoluted oviducts; however, breeding evidence in specimens from Vanua Lava was less pronounced (e.g., smooth ovaries and straight oviducts in all females examined).Gould, 1840, Gray Fantail Monarchidae Neolalage banksiana Matthews, 1928, Buff-bellied Monarch: Figure 3F The Buff-bellied Monarch is in a monotypic genus that is endemic to Vanuatu (Fig. 3F).It occurs from Éfaté north to the Banks Group and its IUCN status is Least Concern.Individuals were easily identified by their striking black-and-white plumage with yellow underparts.Female plumage was slightly muted compared to males.This unmistakeably plumaged monarch-flycatcher was fairly common in forest understory at all sites except Gaua.The distribution of Buff-bellied Monarch mirrors closely that of Vanuatu Honeyeater, Gliciphila notabilis (with the exception of Éfaté), and it is curious that both are absent from Gaua.We observed them, often in vine tangles, in pairs or small family groups and they were frequently heard calling.The call is a long, quavering whistle similar to that given by Clytorhynchus shrikebills.Indeed, where these species overlapped, it was difficult to separate them by this call.Additionally, they gave a harsh, chattering call (e.g., see Macaulay Library 515702).Kratter et al. ( 2006) described a melodious song from Santo Island, but we never knowingly heard this vocalization.Many specimens showed evidence of breeding, including male specimens with enlarged testes and seminal vesicles and females with convoluted oviducts, suggesting recent or ongoing breeding.Stomach contents included arthropods and only 1 specimen, a female from Vanua Lava, was observed in molt (primaries).

Rhipidura albiscapa
Clytorhynchus pachycephaloides Elliot, 1870, Southern Shrikebill: Figure 3G, H The Southern Shrikebill occurs in Vanuatu and New Caledonia (Fig. 3G).The Vanuatu subspecies (griscecens) is found on most islands in the country, including throughout the Banks and Torres groups; however, it is absent from Tanna and Aneityum in the far south, as well as Ambrym in the heart of the archipelago.It is a bird of forest understory where it forages for insects in vine tangles.It is a medium-sized, uniformly brown passerine with a large, gray, hooked bill and dingy white tail tips.Its IUCN status is Least Concern.We observed it in 3 of our 4 survey sites.Curiously, we did not detect it on Éfaté where the WSSE collected 12 Southern Shrikebill in June and July 1926.The whistled vocalizations are similar to those of Buff-bellied Monarch so it is plausible we overlooked vocal birds on Éfaté.We had no trouble locating and capturing multiple individuals at our 3 subsequent camps on Malakula, Gaua, and Vanua Lava, which suggests it was at least inconspicuous or locally absent on Éfaté.Both male specimens from Malakula had enlarged testes and seminal vesicles with no evidence of molt, suggesting they were in breeding condition.Our observations on Gaua suggested birds had just completed nesting.We observed several family groups, including juveniles with black bills and yellow gape flanges (Fig. 3H) and 1 specimen had a bursa of Fabricius (9 × 3 mm).Three Gaua specimens were in molt.Stomach contents included arthropods.The Pacific Robin is a widespread, polytypic taxon that occurs from the Solomon Islands to Samoa.It is easily identifiable based on its tiny size and generally black-and-red plumage with pale forehead and wing patch.Only Cardinal Myzomela (Myzomela cardinalis) is superficially similar in plumage, but M. cardinalis has a relatively long, decuved bill, whereas Pacific Robin has a much shorter, straight bill.Its IUCN status is Least Concern.Five subspecies occur in Vanuatu and we recorded 3 during our survey.Petroica multicolor feminina, so named because males have female-like plumage (Fig. 4C), is endemic to Éfaté; P. m. ambrynensis is widespread across central Vanuatu (Malakula and Gaua on our survey; Fig. 4D); and P. m. soror is endemic to Vanua Lava.We found Pacific Robins to be uncommon on Éfaté and Malakula and rare on Gaua and Vanua Lava.Individuals on Éfaté were vocal and specimens of males had enlarged gonads and seminal vesicles.A female on Gaua had 4 yolks (largest 4 mm).No specimens were molting and stomach contents were arthropods.

Hirundinidae
Hirundo rustica Linnaeus, 1758, Pacific Swallow Zosteropidae Zosterops lateralis (Latham, 1801), Silver-eye Zosterops flavifrons (Gmelin, 1789), Yellow-fronted White-eye: Figure 4E Yellow-fronted White-eye is a Vanuatu endemic (Fig. 4E).It was among the most common birds we observed at all of our survey sites.On Éfaté and Malakula daily counts were from 15-25, whereas counts on Gaua and Vanua Lava ranged from 2-10.Indeed, the IUCN Red List status is Least Concern.Yellow-fronted White-eye was easily identified by its small size and uniformly greenish-yellow plumage with bold white eye ring.Its only congener in Vanuatu, Silver-eye (Z.lateralis), has mostly white underparts with yellow restricted to the throat and undertail coverts.Seven subspecies of Z. flavifrons are described, of which we observed 4: Z. f. efatensis (Éfaté), Z. f. macgillivrayi (Malakula), Z. f. gauensis (Gaua), Z. f. perplexus (Vanua Lava).Specimens from all for survey sites showed evidence of breeding.For example, males had enlarged testes and seminal vesicles and some females had enlarged oviducts and were yolking.Birds on Éfaté comprised a major component of the dawn chorus, but vocal activity at dawn was subdued elsewhere.Most specimens showed no evidence of molt (only a few showed minimal body molt) and stomach contents were mostly small seeds and other plant matter.

Discussion
In this paper, we summarize results of an ornithological survey on 4 islands in Vanuatu.Our total of 35 native species recorded at our survey site on Malakula is the highest single-site total we are aware of in Vanuatu.Kratter et al. (2006) recorded 30 native species at 2 different sites on Santo with a combined list of 33 species, which was the highest single-site total in Vanuatu until our survey.Steadman (2006a) suggests that as many as 50 landbird species occur on Santo, but this number includes grebes, herons, and ducks, which we did not record.On Malakula, as many as 31 species of resident landbirds are known from bones (Steadman 2006a), including 3 species that no longer occur on the island: Spotless Crake, Zapornia (Porzana) tabuensis, and 2 extinct species-a flightless Porzana rail and an Eclectus parrot (Steadman 2006b).Our survey of Malakula produced a large single-site species total, but we do not suggest this to mean Malakula is more diverse than Santo.Indeed, Santo is 52% larger than Malakula and it has 2 montane endemic species (Mountain Starling, Aplonis santovestris and Guadalcanal "Santo" Thicketbird, Megalurulus whitneyi).Diamond and Marshall (1977) tabulated New Hebridean species diversity per island, and they found that the higher diversity of birds on Santo upholds the prediction of the equilibrium theory of island biogeography (MacArthur and Wilson 1967).Clearly, Santo and Malakula are Vanuatu's most species-rich islands because of their size and elevational relief on Santo.Site-specific diversity can be affected by survey effort and habitat heterogeneity; thus, whereas our results set a new bar for species richness at a single site in Vanuatu, our total likely will be surpassed with increased survey effort on Santo.

Summary of breeding evidence
Our surveys in November and December coincided with the previously reported breeding season (Bregulla 1992) of birds in Vanuatu: September to February.This corresponds with the end of the dry season and the onset of the wet season (Bregulla 1992).We observed evidence of breeding in a total of 25 species (Table 3), 15 species on both Éfaté and Malakula, but only 7 species each on Gaua and Vanua Lava.In general, the amount of breeding activity was highest on Éfaté and Malakula and became progressively less evident as we moved north to Gaua, and Vanua Lava.This observation is consistent with the Austral Spring and suggests that breeding occurs later in higher latitudes (i.e., farther south) than lower latitudes in Vanuatu.Kratter et al. (2006) observed increased evidence of breeding on Santo during surveys in October and November, but markedly less evidence of breeding there during a June survey, further supporting a seasonal trend towards increased breeding late in the year.This coincides with a relatively dry period before the onset of the tropical cyclone season from January to April.
Pachycephala chlorura was heard frequently singing at night.Overall, most males had enlarged testes and seminal vesicles and females had enlarged ovaries and yolks with convoluted oviducts.Only some females had brood patches (Table 3) and few individuals had bursae of Fabricius.These details of breeding condition, combined with high vocal activity, suggest birds were at peak courtship with egg laying about to commence.
Malakula Island.The dawn chorus at our camp on Malakula began at 03:30 h when Rhipidura verreauxi sang loudly followed by Pachycephala chlorura at 04:15-04:20 h.Rhipidura verreauxi began singing up to 1 hour prior to first light and we often heard it singing single phrases throughout the night.Other vocal species included Vanuatu Scrubfowl (Megapodius layardi), which we heard singing at night at least once, Mackinlay's Cuckoo-Dove (Macropygia mackinlayi), Ptilinopus greyi, Pacific Imperial-Pigeon (Ducula pacifica), Shining Bronze-Cuckoo (Chrysococcyx lucidus), and Vanuatu Kingfisher (Todiramphus farquhari), T. sacer, and Lalage leucopyga.Many passerines that were highly vocal on Éfaté just a week prior, were not singing on Malakula during our survey, including Petroica multicolor, Myiagra caledonica, and Zosterops flavifrons.Overall, breeding activity appeared to be more advanced temporally than our survey on Éfaté.For example, we noted brood patches in females of the following species: M. caledonica, Pachycephala chlorura, Petroica multicolor, and R. verreauxi, but we found bursae of Fabricius only in single individuals of Glossy Swiftlet (Collocalia esculenta), Todiramphus sacer, Cardinal Myzomela (Myzomela cardinalis), and Island Thrush (Turdus polio-cephalus), suggesting that widespread fledging had not commenced.Furthermore, we did not observe any fledglings or juvenile-plumaged birds.
Gaua Island.The dawn chorus was non-existent at our camp on Gaua.Indeed, compared to our surveys on Éfaté and Malakula, the forests of Gaua were eerily quiet with respect to bird song; only Myzomela cardinalis was active vocally.Lack of bird song suggests that the breeding season had progressed at least past male territorial defense and courtship, and observation of a family group of Southern Shrikebill (Clytorhynchus pachycephaloides) suggests at least some species had already fledged young.We observed enlarged gonads in 4 species: Fan-tailed Gerygone (Gerygone flavolateralis), C. pachycephaloides, Myiagra caledonica, and Petroica multicolor and bursae of Fabricius in Myzomela cardinalis, Rhipidura verreauxi, C. pachycephaloides, and Turdus poliocephalus.Numerous species were in molt, including Palm Lorikeet (Charmosyna palmarum), Clytorhynchus pachycephaloides, Gerygone flavolateralis, Myzomela cardinalis, Pachycephala chlorura, Rhipidura verreauxi, and Turdus poliocephalus, which often commences post-breeding.
Vanua Lava Island.Vocal evidence for breeding on Vanua Lava was minimal.Like Gaua, the dawn chorus was minimal with only Vanuatu Honeyeater Gliciphila notabilis engaging in dawn singing.Otherwise, Macropygia mackinlayi was vocally active throughout the day, but species like Pachycephala chlorura, Rhipidura verreauxi, and Zosterops flavifrons were virtually silent.We noted enlarged gonads in several species of pigeons, including M. mackinlayi, Chalcophaps longirostris, and Ptilinopus greyi, plus Petroica multicolor, Zosterops flavifrons, and Turdus poliocephalus.Brood patches were evident on G. notabilis and Z. flavifrons, and one Z.flavifrons was yolking, suggesting at least those species were incubating and/or laying clutches.

Non-native birds and mammals
We observed 6 species of non-native birds during our surveys: 3 at our survey sites, plus 3 additional species in transit between sites.In general, most non-native bird species in Vanuatu are confined to islands with the greatest Western influence (Bregulla 1992).Indeed, Éfaté and Santo have the most non-native species with lesser numbers on Tanna (Medway and Marshall 1975).However, overall number and diversity of non-native species is far less than other archipelagos in the Southwest Pacific (e.g., Fiji).Red Junglefowl was fairly common at our Éfaté and Malakula sites, but absent from our sites on Gaua and Vanua Lava.This was the only non-native species present in native forest habitats at any of our 4 survey sites.We observed small flocks (N = 1-3 birds) of Rock Pigeon Columba livia in Port Vila.In Vanuatu, C. livia is known only from Port Vila, Éfaté and Luganville, Santo (Dutson 2011, eBird 2017).We observed Common Myna on Éfaté, where it was most common in Port Vila.Our camp was within earshot of a small flock of Common Myna, but they never approached the forest, preferring cattle pastures on nearby Tukutuku Ranch.We also observed Common Myna on Santo (while in transit) where it was uncommon at Luganville Santo-Pekoa International Airport.In addition to Éfaté and Santo, Common Myna occurs on Malo, Paama, Epi, and Tanna (Dutson 2011), but the only records in eBird are from Éfaté, Santo, and Tanna (eBird 2017) highlighting the incomplete nature of eBird records in Melanesia.We observed House Sparrow (Passer domesticus) only in Port Vila, which is the only known location in Vanuatu (Dutson 2011, eBird 2017).We observed one flock of Common Waxbill (N = 14 birds) on Tukutuku Ranch, Éfaté.There was a small population on Santo, which is thought to be extirpated (Dutson 2011); only 2 records (from 1985 and 2002) are in eBird (eBird 2017).This species is not known to occur elsewhere in Vanuatu.Finally, we observed small groups (N = 1-7 birds) of Chestnut Munia (Lonchura atricapilla) on Malakula (Norsup Airport and Lingarak Village), plus 1 flock of 50 birds at Luganville Santo-Pekoa International Airport, Santo.Chestnut Munia is known to occur in Vanuatu only on Santo, Aore, Malo, and Malakula (Dutson 2011), but the only eBird records are from Santo and Malakula (eBird 2017).
In addition to non-native birds, we observed several non-native mammals that pose threats to bird populations in Vanuatu, either directly by predation (cats, rats), indirectly via degradation of understorey vegetation (pigs), or wholesale deforestation for cattle grazing (Steadman 2006a).Medway and Marshall (1975) provide a historical overview of non-native mammalian introductions in Vanuatu.We found pigs and dogs were prevalent in villages, and we observed dogs in interior forest on Malakula where they used forest paths to access interior sections of the island.Rats were noted in villages on all 4 surveyed islands.Kratter et al. (2006) documented 2 species of rats during their survey: Black Rat (Rattus rattus) and Polynesian Rat (Rattus exulans), but we did not set traps to document species diversity during our survey.Finally, we observed cattle grazing on deforested land adjacent to our survey site on Éfaté, and while in transit on Santo, but nowhere else.
Species not recorded at our sites Non-passerines.We failed to detect several species at our field sites that are known to exist on those islands.Vanuatu Scrubfowl was apparently common on Éfaté when the WSSE visited in June and July 1926, as evidenced by a series of 26 specimens at the American Museum of Natural History.It is threatened on Éfaté by human encroachment (Bregulla 1992).Dutson (2011) lists Vanuatu Scrubfowl as present on Éfaté, but the lack of recent records (eBird 2017) suggests it may now be extirpated.The IUCN lists it as Vulnerable with a decreasing population trend owing to unsustainable egg-collecting and loss of lowland forest (IUCN 2016).Indeed, its current stronghold occurs on islands north of Éfaté, such as Ambrym, Malakula, and Santo.We failed to detect Tanna Fruit-Dove (Ptilinopus tannensis) on Vanua Lava, despite the WSSE having collected 3 specimens from 9-12 November 1926.It is likely that we failed to detect P. tannensis on Vanua Lava due to our short survey, not due to its rarity.The IUCN status is Least Concern (IUCN 2016).Fan-tailed Cuckoo (Cacomantis flabelliformis) was also recorded on Éfaté, Malakula, and Gaua by the WSSE; it too was apparently common, with series of specimens collected from the aforementioned 3 islands.We never detected it during our surveys, despite MJA being familiar with its vocalizations from Fiji.Its IUCN status is Least Concern (IUCN 2016); however, this status pertains to a widespread, polytypic taxa that occurs from Australia and New Guinea east to Fiji.It would be informative if unique status was assigned to each of 6 major populations: Australia, New Guinea, Solomon Islands, Vanuatu, New Caledonia, and Fiji.Thus, archipelago-specific population declines (e.g., on Vanuatu) could be better addressed by the conservation community.These issues could be better dealt with if evolutionary significant units were highlighted by a detailed phylogeographic study of this species complex.We failed to detect Barn Owl (Tyto alba) on Vanua Lava, but this is easily attributed to our short stay there (N = 3 days) in primary forest.Palm Lorikeet was fairly common at our site on Gaua, but we did not detect it hiking to Lake Letes, nor on other islands.This lorikeet is thought to be nomadic with historic records from Southern Vanuatu where it no longer occurs (Bregulla 1992).This pattern of nomadism is known from other Vanuatu birds and has been hypothesized to be an adaptation to frequent disturbance from cyclones or population booms in response to resource availability (Diamond 1975, Diamond andMarshall 1976).The IUCN status of Charmosyna palmarum is Vulnerable with a declining population trend (IUCN 2016).
Passerines.We failed to observe Rusty-winged Starling (Aplonis zelandica) from the Banks Islands, despite that the WSSE collected specimens from Gaua and Bligh Islands.They are known as far south as Malakula (Dutson 2011; WSSE, N = 1 specimen), but we failed to record them; their IUCN status is Near Threatened with a declining population trend (IUCN 2016).Melanesian Flycatcher was fairly common on 3 of 4 surveyed islands, but curiously, we did not find it on Gaua.The WSSE collected only 3 specimens from Gaua on 11 September and 23 November 1926 suggesting it is uncommon on that island.Its IUCN status is Least Concern (IUCN 2016).Finally, Gray Fantail (Rhipidura albiscapa) is a forest edge species that was difficult to detect at most of our sites because we focused our surveys on primary forest.We failed to detect it anywhere on Malakula and, interestingly, the WSSE did not collect it there.Its IUCN status is Least Concern (IUCN 2016), and we readily found it in Port Vila, as well as coastal villages on Gaua and Vanua Lava.
Table 3. Breeding evidence from specimens included females that were yolking, had convoluted oviducts, or a brood patch and males with enlarged testes or enlarged seminal vesicles.Behavioral evidence included male territorial vocalizations, adults feeding young, and active nests.The number of sex-specific specimens examined appears after the evidence (e.g., N = 4 means we examined 4 individuals of a particular sex at that site).

Figure 1 .
Figure 1.Map of Southern Melanesia, including from north to south, Temotu Province, Solomon Islands; Vanuatu; and New Caledonia (separated by dashed lines).Our 4 survey sites are marked with black circles and are labeled in chronological order of our survey: 1. Éfaté Island, 2. Malakula Island, 3. Gaua Island, and 4. Vanua Lava Island.

Table 1 .
Details of mist net hours at each of 4 survey sites.See text for total and mean daily mist net hours at each site.

Table A2 .
List of species audio recorded with corresponding Macaulay Library catalog numbers.All recordings are available online (http://www.macaulaylibrary.org).