Native Birds of Lanai, Hawaii

NATIVE BIRDS OF LANAI, HAWAII

LAWRENCE T. HIRAI, 1323-2 Kinau Street, Honolulu, Hawaii 96814

The island of Lanai is a pear-shapedshield volcano, covering361 km2, the sixth largestof the Hawaiian Islands. At its extremes,the islandis 29 km long and 21 km wide, with the highestpoint at Lanaihale, 1027 m (Figure 1; Armstrong1973). Mean annualrainfall variesfrom 25 cm alongthe coastto 89 cm nearthe summit(Armstrong 1973), althougha substantialquantity of water, estimatedto be asmuch as the annualrainfall, is directly interceptedfrom the cloudcover by the vege- tation in the upper mountain areas(Ekern 1964). I did a field study of bird speciesdistribution and relativeabundance on Lanai from August 1975 until November 1976. I conductedsurveys and transect counts during this period to provide data for the United States Department of Agriculture Hawaiian Fruit Flies Laboratory to usein assessingpossible effects of their Lanai fruit fly eradicationpro- gram on nontarget animals. Most of the avianspecies now found on Lanai are introduced; however, some native birds are still present. Ac- countson the native speciesfollow.

ISLAND OF LANAI A native forest may have once coveredmost of Lanai, but by the early 1900s cattle, sheepand feral goatshad destroyedit (Perkins1903, Rothschild 1893-1900, Wilson and Evans 1890-1899). Presentlythe nativeforest covers less than 7% of the islandarea (Armstrong 1973). Today the principal forestedarea on Lanai is the mountainregion, with a great deal of the vegetationconsisting of introducedMolassas Grass(Melinis minutiflora), guava(Psidium sp.), eucalyptus(Eucalyptus sp.), Christmasberry (Schinusterebinthifolius) and Norfolk Island Pine (Araucaria heterophylla). The native ohia-lehua (Metrosideroscollina) and false staghornfern, or uluhe, (Dicranopterissp.) are significantly found only above elevationsof 610 m. Sincethe 1920s most of the central plateau hasbeen in Pineapple(Ariahas comosus) production, oc- cupyingabout 20% of the island(Armstrong 1973). LanaiCity, where most of the populationof 2,200 reside,and Lanai Airport are strategi- cally located on the plateau. About the only area on the plateaunot under Pineapple cultivation is Kanepuu, which has remnantsof a dry native forest that possiblyonce coveredmuch of that sectionof Lanai. The coastal areasof the island are coveredby introducedKoa Haole (Leucaenaleucocephala) and Kiawe (a mesquite,Prosopis pallida) on the southernand westernhalf and a wind-sweptgrassy range and coastal belt of Kiawe on the northern and eastern half. Rather extensive wind-erodedareas are found in many sectionsof Lanai, especiallyin the north end.

Western Birds 9:71-77, 1978 71 BIRDS OF LANAI

The coastline is divided into a Pali Coast on the south and west half from Kamaiki Point to Kaena Point and a BeachCoast along the north and east half. The Pali Coast is dominated by 22 km of sea cliffs, reach- ing heightsgreater than 305 m at Kaholo Pali (Armstrong 1973). Sea caves,arches and stacksare found alongthis coast. The BeachCoast, on the other hand, is low and flat, with broad expansesof alluvium and beachesand no appreciablesea cliffs. Polihua and Hulopoe have ex- tensivewhite-sanded beaches; Manele-Hulopoe and Kaumalapauare the recreation and harbor centers of Lanai.

LANAI AVIAN HISTORY Although the native forest of Lanai wasmuch reducedby 1900, the birdlife was still considered abundant (Munro 1960, Perkins 1903), with a petrel, owl, thrush and six membersof the endemicHawaiian Honey- creeper family (Drepanididae)nesting on the mountain. However, by the 1930s the native avifauna had been virtually eliminated, and until recently only three specieswere consideredpresent. A fourth, the Dark- rumpedPetrel, wasrediscovered on Lanai duringthis study. Extinct birds include races of the Thrush (Pbaeornis obscurus lanai- ensis),Creeper (Loxops maculata montana) and Akialoa (Hemignatbus obscuruslanaiensis), and populationsof Ou (Psittirostrapsittacea) and Iiwi (Vestiaria coccinea). The Lanai Thrush was common in the mountain forest, especiallyat the north and south ends,until the 1920s. It declinedin numbersafter 1923 (Munro 1960), althoughit was still considered"not uncommon"as late as 1934 (Munro in Gregory1935). The Lanai Creeper was commonfrom about 460 m elevationto Lanaihale in the 1890s (Perkins 1903, Rothschild 1893-1900, Wilson and Evans 1890-1899), but scarceby the 1930s, with the last sightingof a pair in 1937 (Munro 1960). The Lanai Akialoa inhabited the upper mountain forestregion and was rare evenin the late 1800s,with the lastdefinite sightingof an individualin 1894 (Perkins1903, Rothschild1893-1900). The Ou was quite common on Lanai in the 1890s but probably disap- pearedaround 1932 (Munro 1960). Similarly,the Iiwi was considered abundantthroughout the islandforest in the 1890s (Perkins1903), still fairly commonup to 1923, but extirpated by 1929 (Munro 1960). The causesof bird extinctions on Lanai are not definitely known, but are believedto include mosquito-borneavian diseasesfrom birds, especiallypoultry, introducedwith the establishmentof the Pineapple plantation in the 1920s (Munro 1960), the destructionof the native mountain forest (Greenway 1967), and, to a limited extent, predation by feral cats (Felis catus) and pigs (Susscrofa) (Munro 1960, Perkins 1903, Rothschild 1893-1900).

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EXTANT NATIVE SPECIES WEDGE-TAILED SHEARWATER, Puffinus pacificus cblororbyn- cbus. This race nests in Hawaii on the Northwestern Islands, offshore islands, Kauai and probably Niihau (Berger 1972). On Lanai a small colony,numbering from 5 to 10 birds,probably nests on Puu_pehe_Is-• land, a seatower about 25 m high and 20 m in diameter,45 m off of the point between Manele and Hulopoe Bays. In June and July 1976, at and after sunset,I observedlight-phase Wedge-tailed Shearwaters flying low over the water toward the islet, circlingthe rock and landingon the grassytop. In August1976 I sawa chick in a hole locatednear the top of PuupeheIsland. By mid-September1976 shearwateractivity around the rock had ended. Other seabirds,notably the Bulwer'sPetrel (Bul- weria bulwerii), may also nest on the island,but their presencethere could not be verified becauseof the difficulty in reachingthe islet. Other isletsand stacksdot the Pall Coastand may alsoprovide nesting groundsfor this shearwater. DARK-RUMPED PETREL, Pterodromapbaeopygia sandwicbensis. This endangeredHawaiian race formerly nested on most of the main islands,but is now consideredrestricted to Maui and Hawaii (Berger 1972). The population on Lanai was believedextirpated by pigsand cats (Munro 1960), but night field work from June to October 1976 confirmedthe presenceof the Dark-rumpedPetrel in the mountainforest (Hirai 1978). A possiblecolony, estimated from callsand sightings to be about 100 individuals, was located in June 1976 at an elevation of 850 m at Kumoa Gulch. Although I found no burrows,the petrels probably nest on the ridge slopes,which are coveredby uluhe fern and ohia-leuha. From the availableinformation, the breedingseason of the Dark-rumpedPetrel on Lanai seemsto be similarto that of the population in Haleakala Crater, Maul, beginningin May and extendinguntil November. WHITE-TAILED TROPICBIRD, Phaethon lepturusdorotbeae. This seabirdis known to nest regularly in Hawaii only on Hawaii, Maui, Kauai and a few of the offshoreislands (Berger 1972). On Lanai I noticedthis tropicbird in all monthsof the year alongthe Pali Coastand in Maunalei and Hauola gulches. It probably also inhabits other gulcheson the northeastside of the mountain. At one time I counted as many as 16 individualsin the gulchesor against.the seacliffs. I found no nestsdur- ing this study, but I observedadults landing on ledgesor enteringholes in cliffs along the coast and in the gulchesin October 1975, from late February through early June 1976 and in August 1976. The remainsof two young, leathered and lacking streamers,were found in Maunalei Gulch in August 1975. From these observations,the breedingseason of the White-tailedTropicbird on Lanai is prolongedand possibly year- round.

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RED-TAILED TROPICBIRD, Pbaetbon rubricauda rotbscbildi. This tropicbird breedson the Bonin and Hawaiianislands, most commonly in Hawaii on the NorthwesternIslands (Berger 1972). On Lanai I found Red-tailedTropicbirds along the Pali Coast,nesting in holesin the high sea cliffs from February through August 1976. UsuallyI sawonly one or two individuals at one time but on 9 June 1976, near Kaholo Pali, I countedas many as 10 adults againstthe sea cliffs and overthe ocean. I noted no Red-tailedTropicbirds in the gulcheson the island. WHITE-CAPPED NODDY, Anous tenuirostris. This tern nests in Hawaii on the Northwestern Islands, offshore islands, and at least on the coastsof Maui and Hawaii (Berger1972). On Lanai a colony of up to 30 light phaseindividuals probably nests and/or roostsyear-round in sea cavesor on the high cliffs at Kaneapua,a point of land adjacentto Kaunolu Bay. I alsosaw a few individualsin the Hulopoe-Manelearea, and other coloniesof White-cappedNoddies may exist along the Pali Coast. I noted other seabird speciesalong the coast of Lanai. Solitary Brown Boobies(Sula leucogaster) and Great Frigatebirds(Fregata minor) were observed along the Pali Coast. Terns (probably Sooty, Sterna fuscata) and noddies (probably Common,Anous stolidus)were noticed out at seaflying low over the water in the directionof Oahu.The Black- crownedNight Heron (Nycticorax nycticorax boactli) was occasionally seenon Lanaiand the speciesis probabl• a regular,though infrequently noticed, visitor from nearby Maui. AMERICAN GOLDEN PLOVER, Pluvialisdominica fulva. This Pa- cific race is the most commonof the migratoryshorebirds on Lanai, found from sea level to Lanaihale. Althougha few birds remainedon the islandthe wholeyear, most of the ploversdeparted for the nesting groundsin Siberiaand arctic America by earlyMay andstarted to return in mid-July. On the nine-holecity golf courseI found plovernumbers increasingfrom less than 5 birds in June to over 30 from October throughApril. In the mountainforest, I notedplovers on the unpaved road. RUDDY TURNSTONE, Arenaria interpres. This shorebirdappears to have a migratory cycle similarto that of the AmericanGolden Plover. I observedflocks of up to 15 turnstonesin tilled Pineapplefields and alongthe coastline,especially from KaiolohiaBay to HalepalaoaLand- ing in everymonth of the year exceptJune. BRISTLE-THIGHED CURLEW, Numenius tabitiensis. This bird is a regular migrant from western Alaska to the Northwestern Hawaiian Is- landsand, in smallernumbers, to the main islands(Berger 1972). On 18 July 1976 I sawa Bristle-thighedCurlew on the sandybeach at Polihua. WANDERING TATTLER, Heteroscelus incanus. I found this winter residentalong the rockyshores, regularly at PuupeheIsland, the Kaunolu

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Bay area, from Kaiolohiato HalepalaoaLanding and at Naha. I sawa few solitarytattlers on Lanaithroughout the year. SANDERLING, Calidris alba. On Lanai this shorebird occurred commonly in flocksof up to five individualsalong the sandyshores of the Beach Coast, especiallyfrom Kaiolohia Bay to HalepalaoaLanding, from mid-Julythrough April. SHORT-EARED OWL, Asio flammeus sandwicbensis. This owl is distributedon all the main HawaiianIslands in a wide rangeof habitats (Berger 1972). On Lanai I found Short-earedOwls in the grasslandson the northern and easternsides of the island, Kanepuu, in or near the Pineapplefields, and over the mountainforest. The populationsize on the islandcould be termed common,with the speciesapparently in no immediatedanger of beingextirpated. Nestinginformation on this owl in Hawaii is scant,and it may breedthroughout the year, dependingon the food supply(Berger 1972, Munro 1960). In Juneand October1976 I found young in the Kakaalaniarea, a MolassasGrass habitat. AMAKIHI, Loxops virens. This speciesinhabits all of the main Hawaiian Islands, divided into four subspeciesfound on Kauai, Oahu, Maui-Molokai-Lanai, and Hawaii. It is believed to be the second mo.•t common of the survivinghoneycreepers (Berger 1972). The Lanai population (L. v. wilsoni) was considered common before the 1920s, but then declined in numbers, possibly due to introduced bird diseases (Munro 1960). More recently it hasbeen saidto be rare (Berger 1972). During this study I briefly observedthis bird in late February 1976 between Hauola and Maunalei gulches. For a few minutes I saw one Amakihi and heard a second in a Norfolk Island Pine. On no other occa- siondid I encounterAmakihi, raisingthe possibilitythat the population on Lanai may be closeto extirpation. APAPANE, Himantione sanguinea. A singlespecies inhabits six of the main Hawaiian Islands and is believed to be the most common of the survivingspecies of honeycreepers(Berger 1972). This bird was considered rather abundant in the Lanai forest in the 1890s (Perkins 1903), but by the mid-1930s only a few remained (Munro 1960). I found Apapanemainly in the native mountainforest, although I noted occasionalindividuals in introduced vegetationat lower mountain eleva- tions. Apapane were most common between Hauola and Maunalei gulchesand at Puu Nene. Duringthis studyI found no nests,but I saw immature individuals in January and April 1976 in the Puu Nene and Maunalei-Hauolaareas respectively. There have been speculationsof interislandflights by Apapane (Berger 1972) and it may be that such movementshave previouslyrestocked the population on Lanai. Itow- ever, today the Apapane population on the island seemsstable and viable, althoughnumbers are small and will probably never exceedthe very low hundredsdue to the quality and quantity of the nativeforest.

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SUMMARY Basedon field work conductedfrom August 1975 until November 1976, speciesaccounts of the native birds on Lanai are given. Five migratoryshorebird species and eightnative nesting species were found on Lanai. The migratory shorebirdswere mainly distributedalong the coastline in the nonsummer months, with American Golden Plovers and Ruddy Turnstonesalso noted in the Pineapplefields. White-tailedand Red-tailedtropicbirds,Wedge-tailed Shearwaters and White-cappedNod- dies were present and evidently breedingalong the Pall Coast. White- tailed Tropicbirdswere also observedin the gulcheson the northeast side of the island. Short-eared Owls were common over much of Lanai, and a small but viable population of Apapane was found in the native mountainforest. Amakihi were seenonly oncein the mountainforest and the island population may be on the verge of extirpation. The Dark-rumpedPetrel was rediscoveredduring this study, probably nesting in the mountain forest.

ACKNOWLEDGMENTS

My appreciationgoes to the many peoplein Honolulu and on Lanai for their kindnessand assistanceduring this study. Specialthanks are' extendedto the personnelof the Hawaiian Fruit Flies Laboratory Lanai field station and Kyong Nan Hirai. Andrew J. Bergerkindly commented on the manuscript. This study was conductedunder the direction of Andrew J. Bergeron funds providedby the Hawaiian Fruit Flies Labora- tory, United StatesDepartment of Agriculture, through the Department of Entomology,University of Hawaii.

LITERATURE CITED

Armstrong, R.W. 1973. Atlas of Hawaii. Univ. Pressof Hawaii, Honolulu. Berger,A.J. 1972. Hawaiian birdlife. Univ. Pressof Hawaii, Honolulu. Ekern, P.C. 1964. Direct interceptionof cloud water on Lanaihale,Hawaii. Soil Sci. Soc. Am. Proc. 28:419-421. Greenway, J. C. 1967. Extinct and vanishingbirds of the world. Dover, New York. Gregory, H.E. 1935. Report of the director for 1934. B.P. BishopMus. Bull. 133. Hirai, L.T. 1978. PossibleDark-rumped Petrel colony on Lanai, Hawaii. Elepaio 38:71-72. Munro, G. C. 1960. Birdsof Hawaii. CharlesE. Tuttle, Tokyo. Perkins,R. C. L. 1903. Vertebrata (Aves). Vol. 1, part 4, pages368-465 in D. Sharp,ed. Fauna Hawaiiensis.Univ. Press,Cambridge, England. Rothschild,W. 1893-1900. The Avifaunaof Laysanand the neighboringislands: with a completehistory to date of the birdsof the Hawaiianpossessions. R.H. Porter, London. Wilson, S. B. and A. H. Evans. 1890-1899. Aves Hawaiiensis: the birds of the Sandwich Islands. R. H. Porter, London.

Accepted 4 August 1978 77 Sketchby Narca Moore