EVOLUTION, ECOLOGY, CONSERVATION, AND MANAGEMENT OF HAWAIIAN BIRDS: A VANISHING AVIFAUNA IRONTISPIICI: Hawai'i '0'0 (1o1< nbilis), largesl of the '0'0's and best-known by the indigenous inhab- itants of Hawai'i. Formerly widespread and ½onon on the island of Hawai'i, it disappeared early in the 20  century, with Ihe last known specimen from Ka'0 Crater on 13 May 1902 (Kepler el ai. in press). Painting by H. Douglas Pram Jr. EVOLUTION, ECOLOGY, CONSERVATION, AND MANAGEMENT OF HAWAIIAN BIRDS: A VANISHING AVIFAUNA J. Michael Scott, Sheila Conant, and Charles van Riper, III, Editors Studies in Avian Biology No. 22 A PUBLICATION OF THE COOPER ORNITHOLOGICAL SOCIETY Cover photograph of 'Anianiau (Hemignathus parvus) foraging on kanawao (Broussaisia arguta) by Jack Jeffrey. STUDIES IN AVIAN BIOLOGY Edited by John T Rotenberry Department of Biology University of California Riverside, CA 92521 Studies in Avian Biology is a series of works too long for The Condor, published at irregular intervals by the Cooper Ornithological Society. Manu- scripts for consideration should be submitted to the editor. Style and format should follow those of previous issues. Price $29.00 for softcover and $48.50 for hardcover including postage and handling. All orders cash in advance; make checks payable to Cooper Orni- thological Society. Send orders to Cooper Ornithological Society, % Western Foundation of Vertebrate Zoology, 439 Calle San Pablo, Camarillo, CA 93012. ISBN: 1-891276-25-5 (cloth) ISBN: 1-891276-18-2 (paper) Library of Congress Control Number: 2001 131292 Printed at Allen Press, Inc., Lawrence, Kansas 66044 Issued: 16 March 2001 Revised: 8 March 2002 Copyright ¸ by the Cooper Ornithological Society 2001 CONTENTS DEDICATION ..................................................... viii LIST OF AUTHORS ............................................... ix INTRODUCTION .................................................. ........... J. Michael Scott, Sheila Conant, and Charles van Riper, III 1 HISTORICAL PERSPECTIVES Introduction ... Charles van Riper, III, Sheila Conant, and J. Michael Scott 14 How many bird species in Hawai'i and the Central Pacific before first con- tact? ................................ John Curnutt and Stuart Pimm 15 Patterns of success among introduced birds in the Hawaiian Islands ...... ............. Michael P. Moulton, Karl E. Miller, and Eric A. Tillman 31 SYSTEMATICS Introduction ........................................ Helen E James 48 Molecular systematics and biogeography of the Hawaiian avifauna ....... .......................... Robert C. Fleischer and Carl E. Mcintosh 51 Evolutionary relationships and conservation of the Hawaiian anatids ..... ................................................ Judith M. Rhymer 61 The interplay of species concepts, taxonomy, and conservation: lessons from the Hawaiian avifauna .......... H. Douglas Pratt and Thane K. Pratt 68 Why the Hawai'i Creeper is an Oreomystis: what phenotypic characters re- veal about the phylogeny of Hawaiian honeycreepers H. Douglas Pratt 81 Phylogenetic placement of the Po'ouli, Melamprosops phaeosoma, based on mitochondrial DNA sequence and osteological characters ............. ................. Robert C. Fleischer, Cheryl L. Tarr, Helen E James, Beth Slikas, and Carl E. Mcintosh 98 STATUS AND TRENDS Introduction ............... J. Michael Scott and Charles van Riper, III 106 The status and population trends of the Newell's Shearwater on Kaua'i: insights from modeling .... David G. Ainley, Richard Podolsky, Leah Deforest, Gregory Spencer, and Nadav Nur 108 Migration of Northern Pintail across the Pacific with reference to the Ha- waiian Islands ......... Miklos D. E Udvardy and Andrew Engilis, Jr. 124 The Hawai'i rare bird search 1994-1996 .............................. ..................... Michelle H. Reynolds and Thomas J. Snetsinger 133 Status and distribution of the Po'ouli in the Hanaw¾ Natural Area Reserve between December 1995 and June 1997 .............. Paul E. Baker 144 ECOLOGY Introduction ......................................... Sheila Conant 152 Drepanidine movements in relation to food availability in subalpine wood- land on Mauna Kea, Hawai'i ...................................... ............... Steven C. Hess, Paul C. Banko, Michelle H. Reynolds, Gregory J. Brenner, Leona P. Laniawe, and James D. Jacobi 154 Breeding productivity and survival of the endangered Hawai'i Creeper in a wet forest refuge on Mauna Kea, Hawai'i ........................... ............... Bethany L. Woodworth, Jay T. Nelson, Erik J. Tweed, Steven G. Fancy, Michael P. Moore, Emily B. Cohen, and Mark S. Collins 164 Significance of old-growth forest to the Hawai'i ',kepa ................ ................................................ Leonard A. Freed 173 Demographic comparisons between high and low density populations of Hawai'i 'kepa .................................... Patrick J. Hart 185 Breeding characteristics of the 'Akohekohe on east Maui ............... .......................... Ellen M. VanGelder and Thomas B. Smith 194 'kohekohe response to flower availability: seasonal abundance, foraging, breeding, and molt ............................................... ...................... Kim E. Berlin, John C. Simon, Thane K. Pratt, James R. Kowalsky, and Jeff S. Hatfield 202 Age-related diet differences in two nectar-feeding Drepanidines: the ',kohe- kohe and the 'Apapane ........................... John H. Carothers 213 LIMITING FACTORS Introduction ............... J. Michael Scott and Charles van Riper, III 220 Limiting factors affecting Hawaiian native birds ....................... ......................... Charles van Riper, III, and J. Michael Scott 221 Habitat use and limiting factors in a population of Hawaiian Dark-rumped Petrels on Mauna Loa, Hawai'i .................................... ........... Darcy Hu, Catherine Glidden, Jill S. Lippert, Lena Schnell, James S. MacIvor, and Julian Meisler 234 Interaction between the Hawaiian Dark-rumped Petrel and the Argentine ant in Haleakalg National Park, Maui, Hawai'i .......................... ... Paul D. Krushelnycky, Cathleen S. N. Hodges, Arthur C. Medeiros, and Lloyd L. Loope 243 Distribution and potential impacts of avian poxlike lesions in 'Elepaio at Hakalau Forest National Wildlife Refuge ......... Eric A. VanderWerf 247 Immunogenetics and resistance to avian malaria in Hawaiian honeycreepers (Drepanidinae) ................... Susan I. Jarvi, Carter T Atkinson, and Robert C. Fleischer 254 Changes in native and introduced bird populations on O'ahu: infectious dis- eases and species replacement ..................................... ................ Cherie Shehata, Leonard Freed, and Rebecca L. Cann 264 What caused the population decline of the Bridled White-eye on Rota, Mar- iana Islands? ............. Steven G. Fancy and Thomas J. Snetsinger 274 The evolution of passefine life histories on oceanic islands, and its impli- cations for the dynamics of population decline and recovery .......... ........................................... Bertram G. Murray, Jr. 281 Newly emergent and future threats of alien species to Pacific birds and ecosystems .... Lloyd L. Loope, Francis G. Howarth, Frederick Kraus, and Thane K. Pratt 291 RECOVERY AND MANAGEMENT Introduction ...................... J. Michael Scott and Sheila Conant 306 Effects of predator control on the survival and breeding success of the en- dangered Hawaiian Dark-rumped Petrel ............................. ............. Cathleen S. Natividad Hodges and Ronald J. Nagata, Sr. 308 Foraging behavior and temporal use of grasslands by NSnS: implications for management ................. Friederike Woog and Jeffrey M. Black 319 An ecosystem-based management approach to enhancing endangered water- bird habitat on a military base ........................ Diane Drigot 329 Why isn't the Nihoa Millerbird extinct? ............................... ................................... Sheila Conant and Marie Morin 338 Reintroduction and translocation of 'Oma'o: a comparison of methods .... ............ Steven G. Fancy, Jay T. Nelson, Peter Harrity, Jope Kuhn, Marla Kuhn, Cyndi Kuehler, and Jon G. Giffin 347 Restoration techniques for Hawaiian forest birds: collection of eggs, artificial incubation and hand-rearing of chicks, and release to the wild ......... .......... Cyndi Kuehler, Alan Lieberman, Peter Harrity, Marla Kuhn, Jope Kuhn, Barbara Mcllraith, and John Turner 354 Conservation status and recovery strategies for endemic Hawaiian birds .. ................. Paul C. Banko, Reginald E. David, James D. Jacobi, and Winston E. Banko 359 Evaluating the cost of saving native Hawaiian birds .................... ............................................ William W. M. Steiner 377 LITERATURE CITED .............................................. 384 DEDICATION This STUDIES IN AVIAN BIOLOGY volume is dedicated to Dean Amadon, Paul H. Baldwin, and David Woodside, colleagues and friends who laid the foundation for the recent renaissance of studies of the endemic birds of Hawai'i and a link with ornithologists of the late 19 th century. It is because many of the researchers in Hawai'i, and those in particular who have contributed to this book, have anchored their scientific premises and hypotheses on the contributions of these three men, that we dedicate this STUDIES IN AvIAN BIOLOGY to them. Dean Amadon was stationed with the U.S. Army in Hawai'i in 1944 and 1945, spending most of his time on the island of O'ahu, and two months on the Big Island as well. His interest in Hawaiian honeycreepers had been aroused earlier while he was at the American Museum of Natural History working with the ornithological collections of Lord Walter Rothschild. In Hawai'i, Amadon worked with Bishop Museum collections and got into the field to observe birds whenever he was free from his military duties. After the war he returned to academia to earn his doctorate at Cornell University. His dissertation, eventually published as The Hawaiian Honeycreepers (Amadon 1950), became a classic work on the systematics of the honeycreepers. It was the first thorough revision of the group based on Mayifs "modem synthesis" of evolutionary theory. While working on the Big Island, Amadon had been assisted by Paul Baldwin, whose research focused on life history and ecology of the honeycreepers. Paul H. Baldwin was one of the true pioneers of Hawaiian ornithology. During the 1930s while Paul was working on his master's of science (on ocean crabs) at the University of Hawai'i, he was selected biologist for the Civilian Conservation Corps, stationed at Hawai'i Volcanoes National Park. It was at this position that Paul began collecting the first quantitative behavioral information on the Hawaiian avifauna. Following World War II, he enrolled at the University of California at Berkeley to complete his PhD. Coupling information that he had collected at Volcanoes National Park during the 1930s with intensive fieldwork in 1948-1949, Paul completed the first intensive behavioral work on banded Hawaiian honeycreepers. His study quantified for the first time physi- ological cycles, population movement patterns, avian diets, and evolutionary patterns in Hawaiian birds. He correlated these data with environmental factors (particularly climate), forest structure, and resource availability. Paul Baldwin's 1953 paper, Annual cycle, environment and evolution in the Hawaiian honeycreepers (Aves: Drepaniidae), still stands as a milestone in Hawaiian ornithol- ogy. Paul's contributions to Hawai'i extend far beyond his 1953 work, with seminal papers on the Nene, a number on introduced birds (e.g., the Red-billed Leiothrix), economic impacts of the in- troduced mongoose, and impacts of cattle grazing on the native forests. David Woodside was 15 years old when he began assisting George C. Munro in the field. Munro later published Birds of Hawaii (1944), which included the first comprehensive survey of the dis- tribution of Hawaiian forest birds since the turn of the century. Woodside has worked with virtually every well-known ornithologist and agency that has engaged in research on Hawaiian birds, and has probably seen more Hawaiian birds and visited more haunts of Hawaiian birds than any living person. He was employed as a wildlife biologist for the Territory and later the State of Hawai'i for many years. After retiring from the state wildlife agency, he began working for the refuge branch of the U.S. Fish and Wildlife Service in 1980, where he continues to work today. Dave joined the Hawaii Audubon Society as a charter member when he was 15, and has contributed his time and expertise to studies and conservation of Hawaiian birds for a lifetime. Although he has witnessed the extinction of many Hawaiian birds, he is among the fortunate few living souls who have seen such birds as the O'ahu 'Alauahio, 'O'fi, Kama'o, and Kaua'i 'O'O. LIST OF AUTHORS DAVID G. AINLEY H. T. Harvey and Associates 3150 Almaden Expressway, Suite 145 San Jose, CA 95118 CARTER T. ATKINSON U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 218 Hawaii National Park, HI 96718 PAUL E. BACER U.S. Geological Survey Pacific Island Ecosystems Science Center P.O. Box 44 Hawaii National Park, HI 96718 (Present address: 8 Raglan Court, Silloth Cumbria, CA5 4BW, UK) PAUL C. BANKO U.S. Geological Survey Pacific Island Ecosystems Research Center Kilauea Field Station, P.O. Box 44 Hawaii National Park, HI 96718 WINSTON E. BANKO U.S. Geological Survey Pacific Island Ecosystems Research Center Kilauea Field Station Hawaii National Park, HI 96718 (Present address: 332 Redwood Place, College Place, WA 99324) KIM E. BERLIN U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Hawaii National Park, HI 96718 JEFFREY M. BLACK Department of Wildlife Humboldt State University Arcata, CA 95521-8299 GREGORY J. BRENNER U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Hawaii National Park, HI 96718 REBECCA L. CANN Department of Genetics & Molecular Biology John A. Bums School of Medicine University of Hawaii at Manoa Honolulu, HI 96822 JOHN H. CAROTHERS Museum of Vertebrate Zoology and Department of Zoology University of California Be/keley, CA 94720 EMILY B. C(HEN U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Building 344 Hawaii National Park, HI 96718 MARK S. COLLINS U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44, Bu.ilding 344 Hawaii National Park, HI 96718 SHEILA CONANT Department of Zoology University of Hawaii at Manoa 2538 McCarthy Mall Honolulu, HI 96822 JOHN CURNUTT Department of Ecology and Evolutionary Biology University of Tennessee Knoxville, TN 37919 REGINALD E. DAVID Rang Productions EO. Box 1371 Kailua-Kona, HI 96745 LEAH DEFOREST EO. Box 6122 Hilo, HI 96720 DIANE DRIGOT Environmental Department Marine Corps Base Hawaii MCBH Kaneohe Bay, HI 96863-3002 ANDREW ENGILIS, JR. Ducks Unlimited, Inc. 3074 Gold Canal Drive Rancho Cordova, CA 95670 (Present address: Department of Wildlife, Fish, and Conservation Biology University of California Davis, CA 95616) STEVEN G. FANCY U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44, Building 344 Hawaii National Park, HI 96718 ROBERT C. FLEISCHER Molecular Genetics Laboratory National Zoological Park Smithsonian Institution Washington, DC 20008 LEONARD A. FREED Department of Zoology University of Hawaii at Manoa Honolulu, HI 96822 JON G. GIFFIN Hawaii Dept. Land and Natural Resources Division of Forestry and Wildlife P.O. Box 4849 Hilo, HI 96720 CATHERINE GLIDDEN Hawaii Volcanoes National Park P.O. Box 52 Hawaii National Park, HI 96718-0052 PETER HARRITY The Peregrine Fund Keauhou' Bird Conservation Center P.O. Box 39 Volcan,o, HI 96785 PATRICK J. HART . Department of Zoology University of Hawaii at Manoa Honolulu, HI 96822 JEFF S. HATFIELD U.S. Geological Survey Patuxent Wildlife Research Center Laurel, MD 20708-4017 STEVEN C. HESS U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Hawaii National Park, HI 96718 CATHLEEN S. NATIVIDAD HODGES Haleakala National Park Resources Management Division P.O. Box 369 Makawao, Maui, HI 96768 FRANCIS G. HOWARTH Department of Natural Sciences Bernice P. Bishop Museum P.O. Box 19000-A Honolulu, HI 96819 DARCY HU Hawaii Volcanoes National Park P.O. Box 52 Hawaii National Park, HI 96718-0052 JAMES D. JACOBI U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Hawaii National Park, HI 96718 HELEN E JAMES Department of Vertebrate Zoology National Museum of Natural History Smithsonian Institution Washington, DC 20560 SUSAN I. JARVl Molecular Genetics Laboratory National Zoological Park Smithsonian Institution 3001 Connecticut Ave. NW Washington, DC 20008 (Present address: Department of Biology University of Hawaii-Hilo 200 W. Kawili St. Hilo, HI 96720) JAMES R. KOWALSKY U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Hawaii National Park, HI 96718 FRED KRAUS Department of Land and Natural Resources Division of Forestry and Wildlife 1151 Punchbowl Street Honolulu, HI 96813 PAUL D. KRUSHELNYCKY U.S. Geological Survey Haleakala National Park Field Station Box 39 Makawao, HI 96768 CYNDI KUEHLER The Peregrine Fund Keauhou Bird Conservation Center P.O. Box 39 Volcano, HI 96785 JOPE KUHN The Peregrine Fund Keauhou Bird Conservation Center P.O. Box 39 Volcano, HI 96785 MARLA KUHN The Peregrine Fund Keauhou Bird Conservation Center P.O. Box 39 Volcano, HI 96785 LEONA P. LANIAWE U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Hawaii National Park, HI 96718 ALAN LIEBERMAN The Peregrine Fund Keauhou Bird Conservation Center P.O. Box 39 Volcano, HI 96785 JILL S. LIPPERT Hawaii Volcanoes National Park P.O. Box 52 Hawaii National Park, HI 96718-0052 LLOYD L. LOOPE U.S. Geological Survey Pacific Island Ecosystems Center Haleakala Field Station P.O. Box 369 Makawao, Maui, HI 96768 JAMES S. MACIVOR 1207 Tedford Way Oklahoma City, OK 73116 BARBARA MCILRAITH The Peregrine Fund Keauhou Bird Conservation Center P.O. Box 39 Volcano, HI 96785 CARL E. MCINTOSH Molecular Genetics Laboratory National Zoological Park Smithsonian Institution Washington, DC 20008 ARTHUR C. MEDE1ROS U.S. Geological Survey Haleakala National Park Field Station Box 39 Makawao, HI 96768 JULIAN MEISLER P.O. Box 851 Burlington, VT 05402 KARL E. MILLER Department of Wildlife Ecology & Conservation P.O. Box 110430 University of Florida Gainesville, FL 32611-0430 MICHAEL P. MOORE U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44, Building 344 Hawaii National Park, HI 96718 MARIE MORIN Department of Zoology University of Hawaii at Manoa 2538 McCarthy Mall Honolulu, HI 96822 MICHAEL P. MOULTON Department of Wildlife Ecology & Conservation P.O. Box 110430 University of Florida Gainesville, FL 32611-0430 BERTRAM G. MURRAY, JR. Graduate Program in Ecology and Evolution 80 Nichol Avenue Rutgers Uniqersity New Brunswick, NJ 08901-2882 RONALD J. NAGATA, gR. Haleakala National Park Resources Management Division P.O. Box 369 Makawao, Maui, HI 96768 JAY T. NELSON U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44, Building 344 Hawaii National Park, HI 96718 NADAV NUR Point Reyes Bird Observatory Stinson Beach, CA 94970 STUART PIMM Department of Ecology and Evolutionary Biology University of Tennessee Knoxville, TN 37919 RICHARD PODOLSKY Avian Systems Fort Lee, NJ 07024 H. DOUGLAS PRATT Museum of Natural Science Louisiana State University Baton Rouge, LA 70893 THANE m. PRATt U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Hawaii National Park, HI 96718 MICHELLE H. REYNOLDS U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Hawaii National Park, HI 96718 JUDITH M. RHYMER Department of Wildlife Ecology University of Maine Orono, ME 04469 LENA SCHNELL US Army, CDR, USAG-HI-PTA Attn: Evironmental Office APO AP 96556-5703 J. MICHAEL SCOTI' U.S. Geological Survey IDCFWRU College of Natural Resources University of Idaho Moscow, ID 83844-1141 CHERIE SHEHATA Department of Genetics and Molecular Biology John A. Burns School of Medicine University of Hawaii at Manoa Honolulu, HI 96822 JOHN C. SIMON U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 44 Hawaii National Park, HI 96718 BETH SLIKAS Molecular Genetics Laboratory National Zoological Park Smithsonian Institution Washington, DC 20008 THOMAS B. SMITH Department of Biology San Francisco State University 1600 Holloway Ave. San Francisco, CA 94132 (Present address: Center for Population Biology University of California Davis, CA 95616) THOMAS J. SNETSINGER U.S. Geological Survey Pacific Island Ecosystems Research Center P.O. Box 1319, Kaua'i Forest Bird Project Kekaha, HI 96752 GREGORY SPENCER P.O. Box 6122 Hilo, HI 96720 WILLIAM W. M. STEINER U.S. Geological Survey Pacific Island Ecosystems Research Center 3190 Maile Way Honolulu, HI 96822 CHERYL L. TARR Department of Biology and Institute of Molecular Evolutionary Genetics 208 Erwin W. Mueller Laboratory Pennsylvania State University University Park, PA 16802 ERIC A. TILLMAN Department of Wildlife Ecology & Conservation EO. Box 110430 University of Florida Gainesville, FL 32611-0430 JOHN TURNER The Peregrine Fund Keauhou Bird Conservation Center EO. Box 39 Volcano, HI 96785 Etak J. TWEED U.S. Geological Survey Pacific Island Ecosystems Research Center EO. Box 44, Building 344 Hawaii National Park, HI 96718 MIKLOS D.E UDVARDY (DECEASED) California State University, Sacramento EPac A. VANDERWERF University of Hawaii at Manoa Department of Zoology Edmonson Hall, 2538 The Mall Honolulu, HI 96822 ELLEN M. VANGELDER U.S. Geological Survey Halemkala National Park Box 369 Mmkawao, HI 96768 CHARLES VAN RIPER III U.S. Geological Survey Forest and Rangeland Ecosystem Science Center Colorado Plateau Field Station P.O. Box 5614 Northern Arizona University Flagstaff, AZ 86011 BETHANY L. WOODWORTH U.S. Geological Survey Pacific Island Ecosystems Research Center EO. Box 44, Building 344 Hawaii National Park, HI 96718 FRIEDERIKE WOOG Libanonstr. 66 70184 Stuttgart Germany Studies in Avian Biology No. 22:1-12, 2001. INTRODUCTION J. MICHAEL SCOTT, SHEILA CONANT, AND CHARLES VAN RIPER, III Hawai'i, a string of high and low islands stretching 1,900 km across the Central Pacific, has long captured the imagination of ornitholo- gists. The Hawaiian Islands are the most isolated archipelago in the world, and as a result, were one of the last places on the planet to be popu- lated (Fig. 1). The islands range from 25 million year-old Kure, at the extreme northwest end of the archipelago, to Hawai'i, the largest, south- ernmost, and the youngest island at less than 1 million years old (Fig. 2; Stearns 1966, Carson and Clague 1995). The climate varies dramati- cally from arid, tropical seashores receiving less than 26 cm (10 in) of precipitation on the lee- ward slopes of the main islands, to the windward peaks of the Alaka'i Swamp on Kaua'i, where it is not uncommon for torrential rains to drop 52 cm (20 in) in a day, or to record 1,152 cm (450 in) in a single year. The tropical lowland areas contrast dramatically with the high alti- tude, alpine ecosystems, and stone deserts, where it freezes every night. The landscape is as varied as it is dynamic. The tropical environ- ments at sea level contrast dramatically with the snow capped peaks of Mauna Loa and Mauna Kea, which reach more than 4,000 m in height above sea level and more than 9,000 m from their base in the ocean from which they were born (Stearns 1966, Carson and Clague 1995). The Hawaiian archipelago is extremely dynam- ic, with Loihi Seamount, an incipient island, presently going through the birthing process at a depth of 950 meters 30 km off the southern coast of Hawai'i (Carson and Clague 1995). Polynesians first reached the Hawaiian archi- pelago about 500 AD, and Europeans not until Captain James Cook's third voyage of discovery in 1778. With a little imagination and use of early voyagers' and naturalists' notes, one can create in the mind's eye a pre-Polynesian Ha- wai'i (Rothschild 1893-1900, Henshaw 1902a; Kirch 1982a, 1985). In these presettlement is- lands, millions of seabirds nested not only on offshore islets, isolated cliff faces, and barren subalpine areas where they are found today, but on the beaches and in adjacent forests, bringing tons of nitrates and phosphates from the sea. The transport of nutrients from marine environments by birds has significant impact on terrestrial en- vironments, resulting in increased plant growth and increases in those species that depend on plants for habitat and food (Polls and Hurd 1996, Ryan and Watkins 1989; Anderson and Polis 1998, 1999). As one moved inland, nu- merous species of geese, including ten that we know were flightless, grazed in the open grass- lands. The forests must have been alive with various species of Hawaiian honeyeaters, honey- creepers, owls, and hawks, flightless species (such as rail and ibis), and a variety of large- billed finches. The dawn song chorus of this ghost avifauna will never again be heard, but one can dream. Captain Cook's third voyage of discovery did not contribute greatly to our ornithological knowledge of the islands. Only 11 species and subspecies were ,described based on specimens collected during Cook's voyage, all from Kaua'i and Hawai'i (Medway 1981). The first compre- hensive characterizations of Hawaiian birds were the almost simultaneous publications by Rothschild (1893-1900) and Wilson and Evans (1890-1899). These detailed descriptions of Ha- waiian birds were augmented by the careful doc- umentation of the natural history and ecology of these birds by Henshaw (1902a,b) and Perkins (1893, 1901, 1903). These works established a foundation from which all current Hawaiian or- nithology is measured. In this monograph, we hope to provide another milestone of informa- tion on the avifauna of the Hawaiian Islands and the surrounding Pacific area, from which during the next century ornithologists might measure future changes in this avifauna. And most cer- tainly there will be changes. Historical changes to the Hawaiian avifauna started early, and only 100 years after Cook's exploration of the islands there were reports of species that had apparently gone extinct (Perkins 1903). At the turn of the century, R. C. L. Per- kins (as cited in Munro 1944:69) wrote: "When I first arrived in Kona, the Great Ohia trees, at an elevation of 2,500 feet, were a mass of bloom and each of them was literally alive with hordes of Crimson 'Apapane and Scarlet 'I'iwi; while continually crossing from the top of one great tree to another, the ''6 could be seen on the wing sometimes six or eight at a time .... The 'Amakihi was nu- merous in the same trees but less conspicuous and occasionally one of the long billed Hem- ignathus. Feeding on the fruit of the Ieie could be seen the Hawaiian Crow commonly and the 'O'fl in great abundance. The picture of this noisy, active, and often quarrelsome assembly 2 STUDIES IN AVIAN BIOLOGY NO. 22 FIGURE 1. The Hawaiian archipelago and other major islands in the Pacific Ocean. Kure Atol o .Midway Islands  Pearl and Hermes Reef Lisianski Island Laysan ß Island Maro Reef Gardner Pinnacles Tern Island La Perouse Pinnacle . French Frigate Shoal., ß Necker Island , Nihoa Kaua'i Ni'ihau  Kaula-  Lana'i '==- Maul Kaho'olawe '-- J Hawai'i  The Hawaiian Islands 100 200 300 Statute Miles FIGURE 2. The Hawaiian Islandsß Detailed maps of individual islands can be found in the chapters that follow, INTRODUCTION--Scott et al. 3 of birds, many of them brilliant colors, was one never to be forgotten. After the flowering of the Ohia was over, the great gathering nat- urally dispersed, but even then the bird pop- ulation was very great." By 1930 however, things had changed greatly when Munro (1944:68) stated: "Since civilization came to the Hawaiian Is- lands, the experience of the native perching birds has been tragic. My conclusions after the survey (1936-1937) were that 25 species have a fair chance of survival, while 30 species were gone or likely to become extinct." Today native birds are almost absent from the remaining lowland forests of Kona. In their place is an eclectic group of alien species, the result of a large number of planned and un- planned releases (see Moulton et al. this vol- ume). Today, only the 'Elepaio (Chasiempis sandwichensis), Hawai'i 'Amakihi (Hemigna- thus virens), 'I'iwi (Vestiaria coccinea), and 'Apapane (Himatione sanguinea) can be seen re- liably, and these not in all areas. The large-billed finches, honeyeaters (species once ubiquitous), 'O'O (Psittirostra psittacea), and 'Oma'o (Myadestes obscurus) are gone, while the 'ke- pa (Loxops coccineus), 'Akiap61'au (Hemig- nathus munroi), and Hawai'i Creeper (Oreomys- tis bairdi) occur in vanishingly small numbers in fewer than five isolated pockets of native for- est. At this writing, the number of free-flying 'Alal (Corvus hawaiiensis) can be counted on one hand. The true magnitude of these losses would, however, not be known until the pioneering re- search of the husband-and-wife team of Storrs Olson and Helen James (James and Olson 1991, Olson and James 1991). They documented the extinction of at least 50% of the Hawaiian avi- fauna prior to the first use of the Linnean System to describe a Hawaiian species. One hundred nine endemic species are known to have oc- curred in the Hawaiian Islands, 35 of which (32%) are still extant. Nineteen additional taxa were extant in the 18 th century, and 55 (50%) are known only from the fossil and subfbssil rec- ord (Table 1). Reasons for losses of many Hawaiian bird species have been well documented, including the destruction of habitat (Cuddihy and Stone 1990) and taking of birds (van Riper and van Riper 1982, Banko et al. this volume, Hu et al. this volume, van Riper and Scott this volume), predatory mammals (Tomich 1969, Kramer 1971, Atkinson 1977), introduced birds (Schwartz and Schwartz 1949, Lewin 1971, Lewin and Lewin 1984, Mountainspring and TABLE 1. BIRDS KNOWN FROM FOSSIL RECORDS OR KNOWN TO BREED IN THE HAWAIIAN ISLANDS Group dan- Popula- Species known ger- tions Spe- ed __ Histor- cies spe- 51 Fossil ic extant cies <50 500 Seabirds 1 22 22 2 2 1 Herons 0 1 0 0 0 0 Ibises 2 0 0 0 0 0 Waterfowl 10-11 3 3 3 0 0 Hawks 2 1 I 1 0 0 Rails 10 4 2 2 0 0 Stilts 0 I 1 1 0 0 Owls 4 1 1 0 0 0 Crows 3 1 1 1 1 0 Honeyeaters 0 6 1 1 1 0 Oldworld Flycatch- ers 0 1 1 0 0 0 Oldworld Warblers 0 1 1 1 0 0 Hawaiian Thrushes 0 6 2 1 0 1 Honeycreepers 13 31 20 9 4 3 Notes: Information on fossil birds includes only those records assigned species status (James and Olson 1991, Olson and James 1991 ). Additional species are being described. Historical status is based on several sources (Scott et al. 1989, Stone 1989, and Pyle 1997). In the last 11 years three species have become extinct: Kaua'i '6'6 (Moho broccatus), Kama'o (Myadestes myadestinus), and Oloma'o (Myadestes lanaiensis) based on the standard of extinct until proven extant (Diamond 1987). The 'l'iwi (Vestiaria coccinea) is declining in numbers and is disappearing froIll areas formerly occupied. The numbers of two other species have de- creased to less than 50 individuals. Species with less than 50 and 500 censused individuals are provided as indicators of jeopardy. The effective population size lbr these species is unknown but likely to be one-half to one-quarter censused population size (Primack 1993). For the 29 species listed by the U.S. Fish and Wildlife Service as endangered, 8 continue to decline, 6 are of unknown status, and 15 are stable in numbers (USFWS 1996a). Scott 1985), and diseases (Warner 1968, van Riper et al. 1986, Atkinson et al. 1993a,b,c, 1995; Jarvi et al. this volume, Shehata et al. this volume). The combined effect of these losses has been summarized in papers by Scott et al. (1986), van Riper and van Riper (1985), Ralph and van Riper (1985), Freed et al. (1993), and van Riper and Scott (this volume). While many species have succumbed to ex- tinction (Table 1), major steps have been taken recently to save Hawai'i's endangered species. The U.S. Fish and Wildlife Service has estab- lished two national wildlife refuges (Hakalau Forest and Kona Forest National Wildlife Ref- uges) on the island of Hawai'i with a primary objective of protecting endangered forest birds. Combined, these preserves total nearly 16,194 ha (40,000 acres). The National Park Service has eliminated goats (Capra hircus) and sheep (Ovis aries) from Hawai'i Volcanoes and Haleakala National Parks. In addition, large acreages are now pig- (Sus scrofa) free in that park. Similar- 4 STUDIES IN AVIAN BIOLOGY TABLE 2. CHECKLIST OF THE BIRDS OF HAWAII NO. 22 Symbols for status R - Resident native species; normal does not leave islands: Re - Resident, endemic species, not extinct; Rx - Resident, endemic species, presumed extinct; Res - Resident; indigenous species, subspecies is endemic; Hawaiian; Ri - Resident; indigenous species, Hawaiian form is not endemic. A - Alien introduced species; resident; normally does not leave the islands: Al - Alien; long established and breeding since before 1940; An - Alien, new introduced since 1950; apparently established; Ax - Alien; formerly long established and breeding for more than 25 years, but now no longer present in Hawaii. E (or T) immediately preceding the genus name designates a species or subspecies currently listed as Endangered (or Threatened) on the Federal List of Endangered species. B - Breeding species in Hawaii, native, most individuals leave Hawaii when not breeding: Bo - Breeder, species breeds only in Hawaii; Bes - Breeder, species also breeds elsewhere; Hawaiian subspecies breeds only in Hawaii; Bi - Breeder, Hawaiian form also breeds elsewhere. V - Visitor species, breeds elsewhere, occurs in Hawaii when not breeding: Vc - Visitor, common migrant to Hawaii; Vr - Visitor, regular migrant to Hawaii in small numbers; Vo - Visitor, occasional to frequent migrant to Hawaii; Vs - Visitor, accidental straggler to Hawaii; Vd = Visitor, accidental straggler to Hawaii, recorded in Hawaii only as dead remains. Common name Scientific name Status GREBES PODICIPEDIDAE Pied-billed Grebe Podilymbus podiceps Ri Horned Grebe Podiceps auritus Vs Red-necked Grebe Podiceps grisegena Vs Eared Grebe Podiceps nigricollis Vs ALBATROSSES DIOMEDEIDAE Laysan Albatross Phoebastria immutabilis Bi Black-footed Albatross Phoebastria nigripes Bi Short-tailed Albatross E-Phoebastria albatrus Vo PETRELS, SHEARWATERS PROCELLARIIDAE Northern Fulmar Fulmarus glacialis Vo Kermadec Petrel Pterodroma neglecta Vs Herald Petrel Pterodroma arminjoniana Vs Murphy's Petrel Pterodroma ultima Vs Mottled Petrel Pterodroma inexpectata Vo Juan Fernandez Petrel Pterodroma externa Vo (Hawaiian Petrel)--Dark-rumped Petrel E-Pterodroma phaeopygia Res sandwichensis White-necked Petrel Pterodroma cervicalis Vo Bonin Petrel Pterodroma hypoleuca Bi Black-winged Petrel Pterodroma nigripennis Vo Cook's Petrel Pterodroma cookii Vs Stejneger's Petrel Pterodroma longirostris Vd Bulwer's Petrel Bulweria bulwerii Bi Jouanin's Petrel Bulweria fallax Vs Streaked Shearwater Calonectris leucomelas Vs Flesh-footed Shearwater Puffinus carneipes Vo Wedge-tailed Shearwater Puffinus pacificus B i chlororhynchus (New Zealand Shearwater)Buller's Puffinus bulleri Vs Shearwater Sooty Shearwater Short-tailed Shearwater Christmas Shearwater (Newell's Shearwater) Townsend's Shearwater Little Shearwater STORM-PETRELS Wilson's Storm-Petrel Fork-tailed Storm-Petrel Leach's Storm-Petrel (Hawaiian or Harcourt's Storm-Petrel)-- Band-rumped Storm-Petrel (Sooty Storm-Petrel)--Tristram's Storm-Pe- trel TROPICBIRDS White-tailed Tropicbird Red-billed Tropicbird Red-tailed Tropicbird Puffinus griseus Vr Puffinus tenuirostris Vo Puffinus nativitatis Bi T-Puffinus auricularis newelli Be Puffinus assimilis Vs HYDROBATIDAE Oceanires oceanicus Vs Oceanodroma furcata Vs Oceanodroma leucorhoa Vr ' Oceanodroma castro Bi Oceanodroma tristrami Bi PHAETHONTIDAE Phaethon lepturus Ri Phaethon aethereus Vs Phaethon rubricauda Bi rothschiMi INTRODUCTION--Scott et al. 5 TABLE 2. CONTINUED Conlmon name Scientific nanle Status BOOBIES SULIDAE (Blue-faced Booby)--Masked Booby Sula dactylatra personata Ri Brown Booby Sula leucogaster plotus Ri Red-footed Booby Sula sula rubripes Ri CORMORANTS PHALACROCORACIDAE Pelagic Cormorant Phalacrocorax pelagicus Vs FRIGATEBIRDS FREGATIDA E Great Frigatebird Fregata minor palmerstoni Ri Lesser Frigatebird Frigata ariel Vs HERONS, EGRETS ARDEIDAE Great Blue Heron Ardea herodias Vs Great Egret Ardea alba Vs Snowy Egret Egretta thula Vs Little Blue Heron Egretta caerulea Vo Cattle Egret Bubulcus ibis An (Green-backed Heron)--Green Heron Butorides virescens Vs Black-crowned Night-Heron Nycticorax nycticorax hoactli Ri IBISES THRESKIORNITHIDAE White-faced Ibis Plegadis chihi Vs GEESE, DUCKS ANATIDAE Fulvous Whistling-Duck Dendrocygna bicolor Ri (White-fronted Goose)--Greater White- Anser albifrons Vs fronted Goose Emperor Goose Chen canagica Vo Snow Goose Chen caerulescens Vs Canada Goose Branta canadensis Vo (Nn)--Hawaiian Goose E-Branta sandvicensis Re Brant Branta bernicla Vo (Whistling Swan)--Tundra Swan Cygnus columbianus Vs Gadwall Anas strepera Vs (European Wigeon)--Eurasian Wigeon Anas penelope Vs American Wigeon Anas americana Vr Mallard Arias platyrhynchos A1, Vo (Koloa)--Hawaiian Duck E-Arias wyvilliana Re Laysan Duck E-Arias laysanensis Re Blue-winged Teal Arias discors Vo Cinnamon Teal Arias cyanoptera Vs Northern Shoveler Arias clypeata Vc Northern Pintail Anas acuta Vc Garganey Arias querquedula Vo Green-winged Teal Arias crecca Vr Canvasback Aythya valisineria Vs Redhead Aythya americana Vs Common Pochard Aythya ferina Vs Ring-necked Duck Aythya collaris Vo Tufted Duck Aythya fuligula Vs Greater Scaup Aythya marila Vo Lesser Scaup Aythya affinis Vr Harlequin Duck Histrionicus histrionicus Vs Surf Scorer Melanitta perspicillata Vs Black Scoter Melanitta nigra Vs Long-tailed Duck Clangula hyemalis Vs Bufflehead Bucephala albeola Vo Common Goldeneye Bucephala clangula Vs Hooded Merganser Lophodytes cucullatus Vs Common Merganser Mergus merganser Vs Red-breasted Merganser Mergus serratot Vs Ruddy Duck Oxyura jamaicensis Vs HAWKS, EAGLES ACCIPITRIDAE Osprey Pandion haliaetus Vo Black Kite Milvus migrans Vs Steller's Sea-Eagle Haliaeetus pelagicus Vs 6 TABLE 2. CONTINUED STUDIES IN AVIAN BIOLOGY NO. 22 Common name Scientific nalne Status Northern Harrier Circus cyaneus Vs Gray Frog-Hawk Accipiter soloensis Vs ('Io)--Hawaiian Hawk E-Buteo solitarius Re Rough-legged Hawk Buteo lagopus Vs Golden Eagle Aquila chrysaetos Vs FALCONS FALCONIDAE Merlin Falco columbarius Vs Peregrine Falcon E-Falco peregrinus Vo FRANCOLINS, OLD WORLD QUAIL, TURKEY PHASIANIDAE Chukar Alectoris chukar A1 Gray Francolin Francolinus pondicerianus An Black Francolin Francolinus?ancolinus An Erckel's Francolin Francolinus erckelii An Japanese Quail Coturnix japonica A1 Red Junglefowl Gallus gallus A1 Kalij Pheasant (Green Pheasant, Common Pheasant)-- Lophura leucomelanos An Ring-necked Pheasant Phasianus colchicus A1 Common Peafowl Pavo cristatus A1 Wild Turkey Meleagris gallopavo A1 NEW WORLD QUAIL ODONTOPHORIDAE California Quail Callipepla californica A1 Gambel's Quail Callipepla gambelii A1 RAILS, GALLINULES, COOTS RALLIDAE Laysan Rail Porzana palmeri Rx Hawaiian Rail Porzana sandwichensis Rx (Hawaiian Gallinule)--Common E-Gallinula chloropus Res Moorhen sandvicensis (American Coot)--Hawaiian Coot E-Fulica alai Res American Coot Fulica americana Vs CRANES GR UIDAE Sandhill Crane Grus canadensis Vs PLOVERS CHARADRIIDAE (Gray Plover)--Black-bellied Plover Pluvialis squatarola Vr (Lesser or American Golden-Plover)-- Pluvialis Mva Vc Pacific Golden-Plover Mongolian Plover Charadrius mongolus Vs Common Ringed Plover Charadrius hiaticula Vs Semipalmated Plover Charadrius semipalmatus Vo Killdeer Charadrius vociferus Vs Eurasian Dotterel Charadrius morinellus Vs STILTS RECURVIROSTRIDAE (Hawaiian Stilt)--Black-necked Stilt E-Himantopus mexicanus knud- Res seni SANDPIPERS, WADERS SCOLOPACIDAE Greater Yellowlegs Tringa melanoleuca Vs Lesser Yellowlegs Tringa flavipes Vr Wood Sandpiper Tringa glareola Vs Solitary Sandpiper Tringa solitaria Vs Willet Catoptrophorus semipalmatus Vs Wandering Tattler Heteroscelus incanus Vc (Siberian Tattler, Polynesian Tattler)-- Heteroscelus brevipes Vs Gray-tailed Tattler Spotted Sandpiper Actiris macularia Vs Whimbrel Numenius phaeopus Vs Bristle-thighed Curlew Numenius tahitiensis Vr Far Eastern Curlew Numenius madagascariensis Vs Hudsonian Godwit Limosa haemastica Vs Bar-tailed Godwit Limosa lapponica Vo Marbled Godwit Limosa kdoa Vs Ruddy Tumstone Arenaria interpres Vc Red Knot Calidris canutus Vs Sanderling Calidris alba Vo INTRODUCTION--Scott et al. 7 TABLE 2. CONTINUED Common name Scientific name Status Semipalmated Sandpiper Calidris pusilla Vs Western Sandpiper Calidris mauri Vo Red-necked Stint Calidris ruficollis Vs Little Stint Calidris minuta Vs Long-toed Stint Calidris subminuta Vs Least Sandpiper Calidris minutilla Vo Baird's Sandpiper Calidris bairdii Vs Pectoral Sandpiper Calidris melanotos Vr Sharp-tailed Sandpiper Calidris acuminata Vr Dunlin Calidris alpina Vr Curlew Sandpiper Calidrisferruginea Vs Buff-breasted Sandpiper Tryngites subruficollis Vs Ruff Philomachus pugnax Vo Short-billed Dowitcher Limnodromus griseus Vo Long-billed Dowitcher Limnodromus scolopaceus Vr Common Snipe Gallinago gallinago Vo Pin-tailed Snipe Gallinago stenura Vs Wilson's Phalarope Phalaropus tricolor Vo Red-necked Phalarope Phalaropus lobatus Vs Red Phalarope Phalaropus fulicaria Vs JAEGERS, GULLS, TERNS, NODDIES LARIDAE South Polar Skua Stercorarius maccormicki Vs Pomarine Jaeger Stercorarius pomarinus Vr Parasitic Jaeger Stercorarius parasiticus Vs Long-tailed Jaeger Stercorarius longicaudus Vs Laughing Gull Larus atricilla Vo Franklin's Gull Larus pipixcan Vs Black-headed Gull Larus ridibundus Vs Bonaparte's Gull Larus philadelphia Vo Mew Gull Larus canus Vs Ring-billed Gull Larus delawarensis Vo California Gull Larus califbrnicus Vs Herring Gull Larus argentatus Vo Slaty-backed Gull Larus schistisagus Vs Western Gull Larus occidentalis Vs Glaucous-winged Gull Larus glaucescens Vo Glaucous Gull Larus hyperboreus Vs Black-legged Kittiwake Rissa tridactyla Vs Gull-billed Tern Sterna nilotica Vs Caspian Tern Sterna caaTia Vs Great Crested Tern Sterna bergii Vs Sandwich Tern Sterna sandvicensis Vs Common Tern Sterna hitundo Vs Arctic Tern Sterna paradisaea Vo Little Tern Sterna albifrons Vs Least Tern Sterna antillarum Vo Gray-backed Tern Sterna lunata Bi Sooty Tern Sterna fuscata oahuensis Bi Whiskered Tern Chlidonias hybridus Vs Black Tern Chlidonias niger Vs (Common Noddy)--Brown Noddy Anous stolidus pileatus Ri (Hawaiian Noddy, White-capped Noddy)-- Anous minutus melanogenys Res Black Noddy Blue-gray Noddy Procelsterna cerulea saxarilis Ri (Common Fairy-Tern, Fairy Tern)-- Gygis alba rothschildi Ri White Tern AUKLETS, PUFFINS ALCIDAE Cassin's Auklet Ptychoramphus aleuticus Vs Parakeet Auklet Aethia psittacula Vd Horned Puffin Fratercula corniculata Vs Tufted Puffin Fratercula cirrhata Vd 8 TABLE 2. CONTINUED STUDIES IN AVIAN BIOLOGY NO. 22 Common name Scientific name Status SANDGROUSE Chestnut-bellied Sandgrouse DOVES Rock Dove (Chinese Dove, Lace-necked Dove)- Spotted Dove (Barred Dove)--Zebra Dove Mourning Dove PARAKEETS Rose-ringed Parakeet CUCKOOS Common Cuckoo Yellow-billed Cuckoo BARN OWLS Barn Owl TYPICAL OWLS (Hawaiian Owl)--Short-earned Owl NIGHTHAWKS Common Nighthawk SWIFTLETS (Uniform, Island or Gray SwiftleO--Guam Switflet KINGFISHERS Belted Kingfisher HONEYEATERS 'O'o'a'a--Kaua'i 'O 'O O'ahu 'O'o (Moloka'i 'O'o)--Bishop's 'O'O Hawai'i 'O'O Kioea CROWS ('Alala)--Hawaiian Crow MONARCH FLYCATCHERS 'Elepaio { Kaua'i 'Elepaio } -- { O'ahu 'Elepaio }-- { Hawai 'i 'Elepaio }- LARKS (Eurasian Skylark)--Sky Lark SWALLOWS Barn Swallow TITS (Japanese Tit, Yamagara)--Varied Tit BULBULS Red-vented Bulbul Red-whiskered Bulbul OLD WORLD WARBLERS (Uguisu)--Japanese Bush-Warbler Millerbird { Laysan Millerbird }-- {Nihoa Millerbird}- THRUSHES, SOLITAIRES (Shama Thmsh)--White-rumped Shama (Large Kaua'i Thrush)--Kg. ma'o (O'ahu Thrush)--'maui Oloma'o {(Moloka'i Thrush)Moloka'i Olo- ma'o}-- PTEROCLIDIDAE Pterocles exustus An COLUMBIDAE Columba livia A1 Streptopelia chinensis AI Geopelia striata AI Zenaida macroura An PSITTA CIDAE Psittacula krameri An CUCULIDAE Cuculus canorus Vs Coccyzus americanus Vs TYTONIDAE Tyto alba An STRIGIDAE Asio fiammeus sandwichensis Res CAPRIMULGIDAE Chordeiles minor Vs APODIDAE Aerodramus bartschi An ALCEDINIDAE Ceryle alcyon Vs MELIPHA GIDAE E-Moho braccatus Re Moho apicalis Rx Moho bishopi Rx Moho nobdis Rx Chaetoptila angustipluma Rx CORVIDAE E-Corvus hawaiiensis Re MONARCHIDAE Chasiempis sandwichensis C. s. sclateri Re C. s. ibidis Re C. s. sandwichensis, ridgwayi, Re bryani ALA UDIDAE Alauda arvensis AI, Vs HIRUNDINIDAE Hirundo rustica Vs PARIDAE Parus varius Ax PYCNONOTIDAE Pycnonotus cafer An Pycnonotus jocosus An SYLVIIDAE Cettia diphone A1 Acrocephalus familiaris A. f familiaris Rx E-A. f kingi Re TURDIDAE Copsychus malabaricus AI E-Myadestes myadestinus Re Myadestes woahensis Rx Myadestes lanaiensis E-M.l. rutha Re INTRODUCTION--Scott et al. 9 TABLE 2. CONTINUED Conmon name Scientific name Status { (Lgna'i Thrush)--Lgna'i Oloma'o}-- (Hawai'i Thrush)--'0ma'o (Small Kaua'i Thrush)--Puaiohi BABBLERS Greater Necklaced Laughing-thrush Gray-sided Laughing-thrush (Melodious Laughing-thrush, Chinese Thrush)--Hwamei (Pekin Nightingale, Japanese Hill-robin)- Red-billed Leiothrix WHITE-EYES (Mejiro)--Japanese White-eye MOCKINGBIRDS Northern Mockingbird STARLINGS, MYNAS European Starling Common Myna PIPITS Olive-backed Pipit Red-throated Pipit American Pipit EMBERIZIDS Yellow-faced Grassquit Saffron Finch (Brazilian Cardinal)Red-crested Cardinal Yellow-billed Cardinal Savannah Sparrow Snow Bunting CARDINALS (American or Kentucky Cardinal)-- Northern Cardinal MEADOWLARKS, GRACKLES Western Meadowlark Great-tailed Grackle FINCHES CARDUELINE FINCHES (Linnet)--House Finch Common Redpoll (Green Singing-Finch)--Yellow- fronted Canary (Canary)--Common Canary HAWAIIAN HONEYCREEPERS FINCH-BILLED HONEYCREEPERS Laysan Finch Nihoa Finch Lgna'i Hookbill Palila Lesser Koa-Finch Greater Koa-Finch (Grosbeak Finch)--Kona Grosbeak Maui Parrotbill SLENDERBILLED HONEYCREEPERS Hawai'i 'Amakihi { Hawai'i 'Amakihi }-- { Maui 'Amakihi }-- O'ahu 'Amakihi Kaua'i 'Amakihi M. l. lanaiensis Rx Myadestes obscurus Re E-Myadestes palmeri Re T1MALllDAE Garrulax pectoralis A1 Garrulax caerulatus A1 Garrulax canorus A1 Leiothrix lutea A1 ZOSTEROP1DAE Zosterops japonicus A1 MIMIDAE Mimus polyglottos AI STURN1DAE Sturnus vulgaris Vs Acridotheres tristis A1 MOTA C1LL1DAE Antbus hodgsoni Vs Antbus cervinus Vs Antbus rubescerts Vs EMBER1Z1DAE Tiaris olivacea An Sicalis fiaveola An Paroaria coronata A1 Paroaria capitata A1 Passerculus sandwichensis Vs Plectrophenax nivalis Vs CARD1NAL1DAE Cardinalis cardinalis A1 1CTER1DAE Sturnella neglecta A1 Quiscalus mexicanus Vs FRINGILLIDAE CARDUELINAE (subfamily) Carpodacus mexicanus A1 Carduelis fiammea Vs Serinus mozambicus An Serinus canaria A1 DREPANIDINAE (subfamily) PS1TT1ROSTR1N1 (tribe) E- Telespiza cantans Re E- Telespiza ultima Re E-Psittirostra psittacea Re Dysmorodrepanis munroi Rx E-Loxioides bailleui Re Rhodacanthis fiaviceps Rx Rhodacanthis palmeri Rx Chloridops kona Rx E-Pseudonestor xanthoph3;s Re HEM1GNATH1N1 (tribe) Hemignathus virens H. v. virens Re H. v. wilsoni Re Hemignathus fiavus Re Hemignathus kauaiensis Re 10 TABLE 2. CONTINUED STUDIES IN AVIAN BIOLOGY NO. 22 Common name Scientific name Status (Lesser 'Amakihi)--'Anianiau (Green Solitaire)--Greater 'Amakihi Lesser 'Akialoa Greater 'Akialoa { Kaua'i 'Akialoa }-- { O 'ahu 'Akialoa }-- {Lana'i 'Akialoa}-- Nukupu'u {Kaua'i Nukupu'u}-- {O'ahu Nukupu'u }-- {Maui Nukupu'u }-- 'Akiap61g'au (Kaua'i Creeper)--'Akikiki (Olive Green Creeper)--Hawai'i Creeper (O'ahu Creeper)--O'ahu 'Alauahio (Moloka'i Creeper)--Kgkgwahie (Maui Creeper)--Maui 'Alauahio { Maui 'Alauahio }-- { Lana'i 'Alauahio }-- (Kaua'i kepa)--'Akeke'e 'kepa { O'ahu ',kepa }-- {Maui ',kepa }-- { Hawai'i 'kepa }- RED AND BLACK HONEYCREEPERS Ula-'ai-hawane 'I'iwi Hawai'i Mamo (Perkins Mamo)--Black Mamo (Crested Honeycreeper)--'kohekohe 'Apapane {Laysan Honeycreeper }- { 'Apapane }-- Po'ouli OLD WORLD SPARROWS (English Sparrow)--House Sparrow WAXBILLS, MANNIKINS Red-cheeked Cordonbleu Lavender Waxbill Orange-cheeked Waxbill (Red-eared Waxbill)--Black-rumped Waxbill Common Waxbill (Strawberry Finch, Red Munia)--Red Avadavat African Silverbill (Ricebird, Spotted Munia)--Nutmeg Mannikin Tricolored Munia Chestnut Munia Java Sparrow Hemignathus parvus Re Hemignathus sagittirostris Rx Hemignathus obscurus Rx Hemignathus ellisianus H. e. procerus Rx H. e. ellisianus Rx H. e. lanaiensis Rx Hemignathus lucidus E- H. l. hanapepe Re H. I. lucidus Rx E-H. 1. qffinis Re E-Hemignathus munroi Re Oreomystis bairdi Re E-Oreomystis maria Re E-Paroreomyza maculata Re Paroreomyza fiammea Rx Paroreomyza montana P.m. newtoni Re P.m. montana Rx Loxops caeruleirostris Re Loxops coccineus L. c. wolstenholmei Rx E-L. c. ochraceus Re E-L. c. coccineus Re DREPANIDINI (tribe) Ciridops anna Rx Vestiaria coccinea Re Drepanis pac(fica Rx Drepanis funerea Rx E-Palmeria dolei Re Himatione sanguinea H. s. freethii Rx H. s. sanguinea Re E-Melamprosops phaeosoma Re PASSERIDAE Passer domesticux AI ESTRILDIDAE Uraeginthus bengalus An Estrilda caerulescens An Estrilda melpoda An Estrilda troglodytes An Estrilda astrild An Amandava amandava A1 Lonchura cantans An Lonchura punctulata A1 Lonchura malacca A1 Lonchura atricapilla An Padda oryivora An Note,: This table is modified from Robert Pyle's 1997 checklist of the birds of Hawaii. In all cases we have deferred to the American Ornithologist Union's 1998 Checklist of North American birds and the 42nd Supplement to the Checklist (AOU 2000) for common and scientific names and sequence of families and species, We have added macrons. diacritical marks, and glottal stops to all common names as indicated by Pyle (1997). Subspecies of resident species known to occur in the islands are indicated in brackets. Common names in parentheses are those commonly used in Hawai'i but not accepted by the AOU Check-list. INTRODUCTIONsScott et al. 11 ly, The Nature Conservancy has pursued an ag- gressive control program for alien species that threaten the viability of native species popula- tions and the ecological integrity of native Ha- waiian ecosystems and established several large biological reserves. While the Sierra Club, Na- tive Plant Society, Hawaii Audubon Society, and a number of state and federal agencies have all taken actions on behalf of Hawai'i's native flora and fauna, despite their efforts and extensive re- search efforts in the last 25 years (Banko et al. this volume, Steiner this volume), populations and species of native birds continue to be lost. Nonnative birds species comprise a large part of the current avifauna (Table 2). If there is to be any hope of retaining even a majority of the currently endangered and threat- ened native Hawaiian species, more aggressive efforts are needed to seriously reduce agents known to be detrimental to native species (Smith 1985, 1989; Cuddihy and Stone 1990, Stone 1989, Banko et al. this volume, Scott and van Riper this volume). Despite widespread docu- mentation of the impact of feral cats (Felis ca- tus) on birds (Eberhard 1954, van Aarde 1978, Jehl and Parkes 1982, Tomkins 1985, Churcher and Lawton 1987, van Reusenburg and Bester 1988, Bloomer and Besler 1992, Seto and Co- nant 1996, Athens 1997, Radunzel et al. 1997), there are currently no cat control programs in place for passerine species and only limited ef- forts on behalf of seabirds (Hodges and Nagata this volume). Likewise, while the impact of rats (Rattus spp.) on Hawai'i's avifauna has yet to be fully documented, Atkinson's (1977) corre- lational study was suggestive, as was the extinc- tion of five populations of native birds on Big South Cape Island in New Zealand shortly after the arrival of the roof rat (Rattus rattus; Atkin- son 1985). Studies in New Zealand (Atkinson and Bell 1973) and elsewhere have shown the strong positive response of native species when nonnative rats are eliminated (Radunzel et al. 1997). In spite of this evidence, predator control programs are rare and are not being implement- ed over areas large enough to elicit a population response by native species. The elimination of rats from Midway Island is an exception (R. Shallenberger, pers. comm.). In the absence of management activities to control or eliminate known causes of mortality to Hawaiian avifauna over areas comparable to the size of the distributional area of the threats, individuals will die, populations will be lost, and species will continue to go extinct. For some threats (e.g., predators, ungulates), known con- trol techniques (e.g., Taylor and Katahira 1988, Katahira et al. 1993) only need be applied at a scale that is meaningful (the distributional area of a population or species). For others, such as avian malaria and avian pox, new techniques such as genetic engineering of disease resistant birds and introduction of sterile male mosquitoes must be developed and applied. A first step to buy time and simultaneously to restore populations of other endemic Hawaiian species (plants and invertebrates) would be to restore the composition and structure of higher elevation xeric and mesic forest habitats on Maui and Hawai'i by eliminating alien animals and plants (e.g., rats, cats, ungulates, and foun- tain grass) from these areas. These recovered and restored habitats would act as refugia from avian diseases so prevalent at lower elevations. The idea for this book came during informal discussions at the 67 th annual meeting of the Cooper Ornithological Society in Hilo, Hawai'i, in April 1997. During that meeting there were 47 presentations on natural history, ecology and taxonomy of Hawaiian birds. We invited select- ed authors of those presentations to submit manuscripts for consideration in a peer reviewed book on the birds of HawaiT To fill gaps in topics covered we solicited eight additional manuscripts. There was a high degree of redun- dancy in references cited among authors. Be- cause of this we chose to create a combined lit- erature cited. Common and scientific names of birds follow the 7 th edition of the American Ornithologists Union Check-list (AOU 1998). Quentin Tom- ich's Mammals in Hawaii (Tomich 1986) was our reference for mammal names. For flowering plants we relied on Manual of the Flowering Plants of Hawai'i (Wagner et al. 1990 a,b). "Pronunciation of Hawaiian names is aided by the use of a reversed apostrophe ('), to indicate the glottal stop, a stopping of sound, as between the vowell sounds in oh-oh in English; and by macrons over vowels--a, , , o, fi--which de- note long stress. An asterisk preceding a place name indicates that pronunciation is uncertain" (Armstrong 1983:231). The orthography follows the revised and enlarged Hawaiian Dictionary (Pukui and Elbert 1986). For place names we followed the revised and enlarged Place Names of Hawaii (Pukui et al. 1976). When names could not be located there the spelling in the Atlas of Hawaii (Armstrong 1983) was followed. This monograph includes 35 papers, most of which were presented at the 67 th meeting of the Cooper Ornithological Society in Hilo, Hawai'i, in April 1997. Each paper has been peer re- viewed by the editors and at least one outside reviewer. We have grouped the 35 chapters in 12 STUDIES IN AVIAN BIOLOGY NO. 22 this book into six sections, each introduced with a historical review. Taken together, they report on the state of our knowledge concerning the Hawaiian avifauna at the end of the 20 th century. Hopefully, this synthesis volume will assist in some small way to help preserve the unique avi- fauna of Hawai'i and the Pacific islands so that future generations will be able to observe and hear some of the incredible sights and sounds that we have been privileged to experience dur- ing our short 'tour of duty' researching one of the most unique avifaunas on this planet. ACKNOWLEDGMENTS We thank Robert Pyle for permission to use a mod- ified version of his Check-List of Hawaiian Birds and for his comments on drafts of Table 2. Sue McMurray tracked manuscripts and correspondence to author's queries. Sue McMurray and Andrea Reese completed the onerous task of combining references from indi- vidual papers into a single combined Literature Cited. Steve Mosher found a second home in the library as he checked references against the original publications. Lenny Freed was instrumental in launching the idea for publishing manuscripts from the Hilo meeting of the Cooper Ornithological Society as an integrated monograph in STUDIES 1N AVlAN BIOLOGY and provided valuable comments on manuscripts. Melissa Madsen read all manuscripts for grammar and adherence to STUDIES 1N AVlAN BIOLOGY format, consistency with place names of Hawa'i, and correct usage of glottal stops, macrons, and diacritical marks in the spelling of Hawaiian words. Kathy Merk's unfailing commitment to completing this book was a huge morale booster; she tracked manuscripts, corresponded with authors, and made edits on manuscripts as needed. John Roten- berry was the epitome of what a professional editor should be; his insightful comments, rigorous attention to detail, and manner of conveying need for change made him a pleasure to work with. H. Douglas Pratt graciously provided a painting of the Hawai'i '0'8 for the frontespiece of this book, as well as the line draw- ings that precede each section. We thank Patrick Ching for the numerous drawings of native Hawaiian birds scattered throughout the text. Jack Jeffrey kindly pro- vided the photograph of an 'Anianiau feeding on a kanawao that graces the cover. Funds for publication of this book and administrative support were provided by the U.S. Geological Survey, Idaho Cooperative Fish and Wildlife Research Unit, and the Department of Fish and Wildlife, University of Idaho, Moscow, Ida- ho. To all these individuals a special mahalo nui loa (deep thanks) for all that you have done. Historical Perspectives Studies in Avian Biology No. 22:14, 2001. HISTORICAL PERSPECTIVES--INTRODUCTION CHARLES VAN RIPER, III, SHEILA CONANT, AND J. MICHAEL SCOTT The record of Hawai'i's avifauna is one of change; a change that is reflected in steadily di- minishing numbers of species and abundance (Pratt 1994). Our historical perspectives provide insights into how many species there were and some documentation of their distribution, but only minor insights into their abundance, with size, shape, and bill forms allowing vague in- ferences concerning niches occupied and re- sources exploited. Nothing is known of clutch sizes, population characteristics, or ecological interactions of extinct species. For these reasons, more than 50% of Hawai'i's bird species will always be a ghost avifauna. The history of ornithological exploration in Hawai'i is a legacy of missed opportunities, with the first extensive surveys of the avifauna com- ing 100 years after the discovery of the islands by Europeans in 1778 (Olson and James 1994a). Historically, recorded species are but a small fraction of what occurred in the islands prior to European colonization. Some species were sim- ply overlooked; the Po'ouli (Melarnprosops phaeosorna) was not discovered until 1972 (Cas- ey and Jacobi 1974). Olson and James (1991, James and Olson 1991) nearly doubled the known number of endemic species based on their descriptions of new species from fossil and subfossil remains. New discoveries of fossil spe- cies continue today. In the first chapter of this volume, Curnutt and Pimm estimate that the Pacific avifauna was composed of nearly 1,500 species, of which ap- proximately 240 survive. For example, they es- timate that there were 12 species of rails endem- ic to the Hawaiian Islands, versus the 7 currently described (Olson and James 1991; Table 2). In the second chapter, Michael Moulton and his co- authors document the introduction of 140 spe- cies in 14 different orders and ask, "Why do some introduced species succeed and others fail?" 14 Studies in Avian Biology No. 22:15-30, 2001. HOW MANY BIRD SPECIES IN HAWAI'I AND THE CENTRAL PACIFIC BEFORE FIRST CONTACT? JOHN CURNUTT AND STUART PIMM Abstract. Since European settlement, extinctions of Pacific island birds have been widespread and well documented. Subfossil evidence indicates that the Polynesians caused extinctions of an even greater magnitude. Estimating the prehuman Pacific avifauna is difficult because the existing fossil record is inevitably incomplete. We use the theoretical framework of island biogeography to make estimates of the numbers of endemic rails, parrots, pigeons and doves that existed in the Pacific before human contact. We formulate two sets of estimates for each taxon by assuming that: (1) endemism is defined as a distribution limited to a single island, and (2) endemism is a distribution limited to a single-island group. These two assumptions lead to different results (884 compared with 242 endemic species). We refine our predictions by applying topographical and disturbance parameters. Our best estimate is that 332 endemic species of the three taxa once existed in the Pacific, of which 210 are not accounted for in the paleontological and historical data. Applying this ratio of known to missing species for all landbirds, we estimate the original Pacific avifauna to be composed of less than 1,500 species, of which approximately 230 survive. Our estimate of the original Pacific avifauna falls be- tween two earlier conflicting predictions (800 and much greater than 2,000). Our predictions of the number of species missing on each type of island are testable. Our results can be used to focus research efforts on islands that are more likely to have held species of interest. Furthermore, our results can be interpreted to predict the risk of future extinctions that may result from habitat loss or rising sea levels. Key Words: biogeography; doves; extinctions; Pacific Islands; parrots; pigeons; rails; sea level; tsu- namis. The Hawaiian Islands form one of the largest and most diverse archipelagoes in the Pacific. As a group, they lead the world in numbers of his- torically extinct and currently endangered spe- cies of birds (King 1985). This dismal legacy, however, did not befall the Hawaiian Islands alone. Untold bird extinctions doubtlessly oc- curred across the Pacific over the four millennia since humans first set sail there. What was the magnitude of the loss of bird species in the Pa- cific? "The Pacific" denies an easy definition. De- fined in the context of human settlement over the last 4,000 years, we will consider 41 island groups (Fig. 1). They span the Hawaiian Islands in the northeast, west to the Marianas and Palau, southwest through Vanuatu, south to New Zea- land and east to Easter Island. Pratt et al.'s (1987) field guide covers all but Vanuata (for which see Bregulla 1992), New Zealand (see Falla et al. 1983), and Easter (which has no ex- tant landbirds). There are roughly 240 extant native species of landbirds in this region (Falla et al. 1983, Pratt et al. 1987, Bregulla 1992). The largest families are Pachycephalidae (whistlers; 40 spp.), Columbidae (pigeons and doves; 34 spp.), Muscicapidae (Old World flycatchers; 28 spp.), Rallidae (rails; 21 spp.), Psittacidae (parrots; 19 spp.), and Fringillidae (Hawaiian honeycreepers; 19 spp.). To the above number of species we must add those that we know once existed but are now known only through historical records and fos- sils. Among the islands of the Pacific, the many vertebrate extinctions that occurred since the sixteenth century subsequent to the arrival of European explorers are well documented. For example, Diamond (1984) reported that, since 1600, Micronesia and Polynesia suffered rough- ly 100 bird species extinctions. The forces re- sponsible for the loss of these species were the same as those that operate today, primarily hab- itat loss and the introduction of exotic species (Steadman 1997a,b). A much greater extinction event preceded the arrival of Europeans and was concurrent with the first human contact (Stead- man 1997a,b). Beginning about 4,000 years ago with Melanesia and Micronesia and ending about 1,500 years ago with Hawai'i, Easter Is- land, and New Zealand, humanity brought the last habitable places on Earth under its domain (Rouse 1986). European explorers found well-developed, ag- ricultural-based societies on all of the larger Pa- cific islands. It is not known how many of the smaller, less suitable islands were visited only temporarily by the wandering islanders (Oliver 1961). Habitat loss and exotic species (including dogs and pigs) doubtlessly caused the extinction of many species of endemic birds on the per- manently settled islands. Even on smaller unin- habited islands endemic species, many of them flightless rails that had evolved in the absence 15 16 STUDIES IN AVIAN BIOLOGY NO. 22 14. "24 2O FIGURE 1. x,6o ' The islands of the Pacific. Numbers refer to 34 ß tie, 40' island groups referred to in the text and listed in Table 1. of terrestrial predators, could have been har- vested to extinction by temporary human occu- pants. We have evidence of these unrecorded extinc- tion events in the fossil record (Olson and James 1982a, 1991; Milberg and Tyrberg 1993). Ar- cheological efforts in Hawai'i by Olson and James (1982a, 1991; James and Olson 1991) and throughout the rest of the Pacific (Balouet and Olson 1987; Steadman 1991, 1992, 1993, 1997a,b; Kirch et al. 1995), have uncovered a large number of avian fossils that were depos- ited concurrently with early human occupation of the islands. Not all islands have been searched, and even if they were, it is unlikely that all extinct species would be found. Thus, the total number of extant and extinct species identified to date is an underestimate of the di- versity of the prehuman Pacific avifauna. An exact count of the number of landbird spe- cies known only as fossils is difficult to tally because they are not clearly enumerated in some published accounts. The Hawaiian Islands held 62 fossil species (James and Olson 1991, Olson and James 1991) and New Zealand held 44 spe- cies (Steadman 1995). The other islands of the Pacific that have been searched held something less than 100 additional species (Steadman 1995). Thus, roughly 200 species of Pacific landbirds are known only from the fossil record. Summing the number of extant, historically extinct, and prehistorically extinct (fossil) spe- cies, there are 540 known species of landbirds in the Pacific. This number is too low because the fossil record is incomplete. An accurate es- timate of the prehuman Pacific avifauna depends on an accurate estimate of the "missing" fossil species. Pimm et al. (1994) estimated the prehuman number of Pacific island landbirds by applying sampling analyses to fossil data. Briefly, given the number of species known only by fossils, those known by modern observations (i.e., those that still survive and those extinct since Euro- pean colonization), and those known by both fossils and modern observations one can deduce the number of "missing" species from an island. Applying this method to data on the landbirds HOW MANY BIRD SPECIES--Curnutt and Pimm 17 of the tropical Pacific (including New Caledo- nia), Pimm et al. (1994) deduced that the num- ber of known fossil species (ca. 200) is only half of the actual number of species that disappeared before European colonization. Pimm et al. (1994) estimated the original avifauna to include nearly 800 species of landbirds. Excluding data from New Caledonia and including data l¾om New Zealand, to fit the boundaries to the current study, does not appreciably change these esti- mates. A much higher estimate of the original Pacific avifauna was proposed by Steadman (1995, 1997). On finding fossil evidence of up to three or four now extinct species of flightless rails on islands he investigated, Steadman (1995, 1997a,b) suggested that the 800 major islands of the Pacific held more than 2,000 species of this taxon and lower numbers of other taxa--all driven to extinction as a result of first human contact. Steadman's (1995) approach set the question of original avifauna in the context of island biogeography. In this paper we apply a robust theoretical framework, island biogeography theory (Mac- Arthur and Wilson 1967a), to the Pacific islands to determine the number of islands that could have held endemic species of rails (Rallidae), pigeons and doves (Columbiformes), and parrots (Psittaciformes). We chose these taxa because they are well represented in the fossil record. Thus, we do not estimate the entire prehuman landbird fauna; instead our results can indicate the magnitude of the loss of bird diversity that has occurred since first human contact. We in- clude in our analyses all named islands of New Zealand, Micronesia, central and eastern Mela- nesia, and Polynesia that experienced first hu- man contact no earlier than 4,000 years before present (Rouse 1986). Unlike Steadman (1995, 1997), we incorporate data on habitat diversity, changing sea levels during the Holocene, and tsunamis. Each of these factors influences the effective size of islands for landbirds. Put sim- ply, MacArthur and Wilson's (1967a) theory of island biogeography predicts more species on larger islands and those close to a source of im- migrants, and fewer species on small or isolated islands. We perform two distance analyses: dis- tance-from-source, as proposed by MacArthur and Wilson (1967a); and, distance between is- lands--isolated islands are more likely to pro- duce species endemic to one island than those that have very near neighbors (Mayr 1963). By applying reasonable assumptions to this ques- tion, we hope to develop a more accurate esti- mate of the prehuman Pacific avifauna than has been produced to date. We first identify those islands of the Pacific that have the potential to maintain populations of landbirds. We then extrapolate the numbers of endemic rails, pigeons, and parrots that could have existed on all of these islands by applying the known maximum of each taxon recorded on different island sizes and types. In lhct, we cal- culate two estimates of the number of endemic species by using two definitions of endemism. We then refine our estimates by considering eco- logical and environmental characteristics. IDENTIFYING THE BIRD ISLANDS We do not expect all islands of the Pacific to hold birds. Some islands are too small to support viable populations of landbirds. Some islands may also fall outside of the known range of the taxa we are investigating. These limitations to bird distribution are diagrammed in Figure 2 Our first task, then, is to estimate how many islands there are in the Pacific, and which of these could support a population of landbirds. How MANY ISLANDS No one knows how many islands there are in the Pacific Ocean. Estimates range from 30,000 to less than half of that number (Bryan 1963). The distribution of island sizes is fractal--that is, as one looks at the Pacific at finer scales, one finds more islands in a characteristic way. Thus, most islands are very small. We limited our data to named islands. We obtained gazetteer data (latitude, longitude, name) from the U.S. De- fense Mapping Agency's (DMA) database avail- able on the internet. This search yielded 3,463 islands. We assigned each island to an island group according to an arbitrary grouping scheme. Ob- vious archipelagos were identified as groups (e.g., the Gilbert Islands), as were single islands not obviously associated with an archipelago (e.g., Rapa). The result was 41 island groups (Table 1; Fig. 1). As described below, we first grouped islands that are very close to each other. Our primary reason for this was to add small islets to the larger islands that they surround and to unite many "islands" that occur as parts of individual atolls. Second, we determined which islands are too far from a source of immigrants for each taxon. Finally, we determined the size and topography of each island. ISLANDS AND ISLETS If two islands were near enough to each other to allow a species to move between them, then neither would produce an endemic species (Ricklefs and Schluter 1993). But how close is close enough? No data exist on this subject for birds in the Pacific. We know that the limiting distances between islands are surely taxon spe- 18 STUDIES IN AVIAN BIOLOGY NO. 22 Species' distribution limit Region of possible endemism Lack of isolation Island size FIGURE 2. Theoretical framework for endemism of Pacific island birds. Islands that are too small to maintain persistent populations will not produce endemic species (lower size limit), nor will larger islands subject to inhibitory disturbance regimes (effective lower size limit). Some islands are close enough to allow genetic exchange between populations and will not produce endemic species (lack of isolation), while others lay outside of the distribution of some taxa (species' distribution limit). cific and this, in turn, is affected by the mode and propensity of movement exhibited by each taxon. For the three taxa we consider in this pa- per, rails have a higher wing load (ratio of weight to wing area) than pigeons or parrots (Raynet 1988). Thus, it would take relatively more energy for a rail to fly a fixed distance than it would a pigeon. Left free to speculate, we chose a minimum distance equivalent to 0.1 ø of latitude or longitude ( 11 km at the equator) as sufficient for allowing isolation of breeding pop- ulations. We chose this distance primarily for ease of calculation, but also we feel that such a distance would provide an adequate barrier to movement for rails--the most stationary taxon because of its propensity to quickly evolve to- ward flightlessness (Trewick 1997). We summed the sizes of all islands that were closer than 0.1 ø of latitude or longitude to each other. This grouping scheme reduced our data to 788 island sets. Hereafter, we refer to island sets as "islands." WHICH ISLANDS ARE TOO FAR Landbirds are not distributed evenly across is- lands. Just as islands that are too close will pro- hibit divergence; islands that are too distant from a source population may not be colonized at a rate sufficient to allow persistence (Ricklefs and Schluter 1993). We tested for the effect of distance-from- source on the distribution of each of our three taxa with multiple regressions. All of the taxa we consider in this paper have their origins in the Old World (rails: Ripley 1977; pigeons: Goodwin 1983; parrots: Forshaw 1977). We used Map © (Apple Computers, Inc.) software to determine distances between geographic centers of island groups and the following (geologically) continental source areas: Australia (Brisbane), Papau New Guinea (New Britain), Philippines (Manila), and Taiwan (Taipei). Since island size is the most effective predictor of species diver- sity (MacArthur and Wilson 1967a), we per- formed stepwise multiple linear regression of the number of species on total area of each island group, then added distance. We repeated this process for each of the distances generated from the four sources listed above. At best, these multiple regressions only weak- ly explained the variation in species numbers with distance (R < 0.2) and were only signifi- cant for parrots and pigeons (P < 0.05). For this analysis, it is better for the data to speak for themselves. Figure 3 shows the distribution of rails, parrots and pigeons among the 41 island groups of the Pacific. Rails arc found throughout the region, reaching the most remote groups in- cluding Hawai'i and Easter Island. Paradoxical- ly, rails, for which even the largest ocean is not HOW MANY BIRD SPECIES--Curnutt and Pimm 19 TABLE 1. ISLAND GROUPS OF THE PACIFIC OCEAN IN- CLUDED IN OUR ANALYSES No. of Group island Topogra- Group number sets Area (km 2) phy Melanesia Vanuatu 1 38 11,400 H Fiji Islands 2 74 1,860 H Micronesia Palau 3 8 447 H Yap 4 2 175 H Chuuk 5 21 230 L Mariana Islands 6 13 910 H Pohnpei 7 2 360 H Kosrae 8 1 100 H Marshall Islands 9 28 255 L Gilbert Islands 10 18 290 L Nauru 11 2 36 L Polynesia NW Hawai'i 12 2 8 L Hawai'i 13 9 16,700 H Wake 14 1 230 L Johnson Atoll 15 1 2 L Howland 16 1 10 L North Line Islands 17 7 745 L Phoenix 18 5 37 L Tuvalu 19 6 27 L Rotuma 20 1 49 H Wallis and Futuna 21 2 275 H Samoa 22 8 3,500 H Tokelau Islands 23 3 13 L North Cook Islands 24 5 10 L Tonga Islands 25 18 563 H Niue 26 1 258 L South Cook Islands 27 9 234 H South Line Islands 28 2 8 L Marquesas Islands 29 11 1,062 H Society Islands 30 10 1,710 H Tuamotu Arch. 31 11 248 L Gambier 32 6 21 L Pitcairn Islands 33 2 8.5 H Rapa 34 1 40 H Tabuai Islands 35 4 120 H Easter Island 41 1 170 H Kermadec Islands 36 2 34 H Norfolk 37 1 37 H Lord Howe 38 1 10 L New Zealand 39 33 267,800 H Chatham Islands 40 4 1,085 H "Group Number" refers to numbers shown on Figure 1. Island sets are named Islands that are within 0.1 ø latitude and longitude of each other. We include only those sets with combined areas of >150 HA. Topogra- phy is either high relief (H) or low-relief (L). large enough to prohibit colonization, can quick- ly evolve to flightlessness (Diamond 1991). The distribution of pigeons has apparently been lim- ited by the vast expanses of ocean that isolate Hawai'i and Easter Island, for neither has ap- parently held this taxon. For Easter Island, the nearest island to have ever held a pigeon is Pit- cairn (1,600 km), and for Hawai'i, it is the North Cook Islands (3,500 km). Parrots have been found on Easter but not the Hawaiian Islands (nearest island with parrots-Marquesas, 3,800 km distant). For our analyses, therefore, we consider all islands of suitable size as potential sites for rail colonization; all but the Hawaiian and North- west Hawaiian Islands for parrots; and, all but the Hawaiian groups and Easter Island for pi- geons. SIZES OF ISLANDS The final parameters we consider in determin- ing which island sets could maintain populations of landbirds are size and topography. We ob- tained data on the sizes of islands from various sources in the literature and from direct mea- surements from maps (ranging in scale from 1: 10,000 to 1:300,000). Some islands listed in the DMA database were not found on maps (or re- ferred to in any literature we searched), thus, we have no data on their sizes. However, we are confident that we have size estimates for all of the major islands (i.e., > 2 km 2) and for many lesser islands, and those with missing data are from the smallest size classes. Our confidence lies in the fact that island sizes fall within a class of negative exponential distributions known as Zipf-Mandelbrot (Fairthorne 1969). For the is- lands for which we have data, we plotted the size distributions on log-log axes. The Zipf- Mandelbrot distribution predicts a straight line for this graph (Fig. 4), and we can interpret de- viations from the linear fit as "missing" islands. By extending the linear fit below 1 km 2 to our smallest recorded island size (10 ha), we predict that about 800 islands are missing from our is- land size data set. While landbirds do occur on very small is- lands in the Pacific, these are members of sat- ellite populations of larger nearby islands. For example, the Antipodes Island Parakeet (Cy- anoramphus unicolor) is found in low numbers on Archway Island (6 ha)--the smallest of the Antipodes Islands (Taylor 1985). The species is also found on the 54-ha Bollons Island, which is much less than 1 km from Archway Island. The greatest part of this species' population, however, is on the 20 km 2 Antipodes Island-- about 1 km from Bollohs. The loss of the An- tipodes Island population would probably lead to the eventual extinction of this species. It would not make ecological sense to identify Archway Island as one suitable for sustaining a population of parrots. Similarly, we can safely ignore the existence of the 800 "missing" is- lands in our data because they are too small to hold endemic species of landbirds. The smallest Pacific island known to hold an endemic rail is Wake Island, 6.5 km 2 and home 20 STUDIES IN AVEAN BIOLOGY NO. 22 'R ' R,P,D ' RD' .p  . R,P % R,P,D ;tO' 40' FIGURE 3. The distribution of rails (R), parrots (P), and pigeons and doves (D) among the Pacific islands. Numbers correspond to group names in Table 1 and indicate island groups that hold none of the three taxa mentioned above. to Rallus wakensis. The smallest island to hold an endemic pigeon is 28 km 2 Maketea (Tuamotu Archipelago), home to Ptilinopus chalcurus; and the smallest island to hold an endemic parrot is Norfolk Island (33.7 km 2) where remains of Nestor produetus have been recovered. These minima may not be actual; all islands have not been sampled. We performed a Monte Carlo simulation (Efron and Tibshirani 1993) to predict the minimum size of an island that should support an endemic species from the ob- served distribution of island sizes with endemic species. Using data on island sizes, we randomly selected a number of islands equivalent to the number that we knew held endemic species of each taxon. For example, 23 islands held at least one endemic species of rail. We randomly se- lected 23 islands from the entire set of 834 and recorded the minimum size of this subset. We then calculated the mean minimum value of 100 repetitions. By repeating this process with in- creasing cutoff values applied to the entire data set, we determined the lower 95% confidence limit within which our known minimum island size fell (Fig. 5). Some islands have held more than one en- demic species of a taxon. For parrots and pi- geons there were one and two islands, respec- tively. For these taxa we could not perform the above described simulation to determine the minimum island sizes for two or more species-- the sample size is too small. For rails, however, of which 10 islands held more than one endemic species, we could estimate the minimum island size for two species by applying the simulation (with a sample size of 10). To determine which islands could have held more than two species of rail (or more than one species of parrot or pigeon), we assumed that the smallest island for which we had data was the actual minimum. TYPES OF ISLANDS Our measure of habitat diversity was very coarse. We described islands as "high-relief" or HOW MANY BIRD SPECIES--Curnutt and Pimm 21 0.5- 0 i   4 5 6 Log Size (ha) FIGURE 4. The relationship between island sizes and their frequency. The linear fit was calculated after excluding the two smallest size classes (open circles) and the three largest size classes (not shown). The area within the triangle represents islands with size data missing from our data set, assuming island sizes ex- hibit a Zipf-Mandelbrot distribution. "low-relief." High-relief islands were those de- scribed in the literature as volcanic, hilly, or mountainous or whose representation on maps included hachures. Low-relief islands were all of those described as atolls or were lacking ha- chures on maps that normally include such data. High-relief islands are rich in habitat diversity compared to low-relief islands (Adler 1992). We apply the same topography to entire groups by summing the areas of all islands within groups and defining them as high relief if > 50% of the total area is attributed to high-relief islands. EXTRAPOLATING ENDEMICS To estimate the potential number of endemic species that each taxon held, we determined the known maximum number of endemics (living and fossil) on islands of different sizes and to- pographies throughout the Pacific. After esti- mating the size of the smallest islands which we would expect to find endemics on, we used these numbers to predict the maximum numbers of en- demic species with reference to the distribution of island sizes and topographies within each is- land group (Fig. 6). We tallied the number of known endemics and the number of predicted endemics across taxa for each island group then 5000- 4500 4000 3500 3000 2500 2000  15002 1000 500. 0; ....... o Pigeons (B) ........ ,.- ........ Rails (C) ........  ........ Parrots (A) Predicted Minimum size (ha) FIGURE 5. Results of a simulation whereby we randomly selected a number of islands equivalent to the number occupied by endemic species of each taxon. The x-axis represents the lowest value in the data set for each simulation, the y-axis is the 95% lower confidence limit of the mean of 100 repetitions. A, B, and C represent the actual minimum sizes for parrots, pigeons, and rails, respectively. The vertical lines intercept the x-axis at the smallest island size we would expect to find endemics of the respective species. 22 STUDIES IN AVIAN BIOLOGY NO. 22 -4 ß Low-relief islands [] High-relief islands / (12) - 3 )8) - 2 J (1) .................................. (1) J (4) (4,) 1 Log Size (ha) FIGURE 6. The size distribution of islands of the Hawai'i group classified as high relief and low relief. The solid line indicates the maximum number of endemic rails found on all high-relief islands in the Pacific while the dashed line indicates maxima for low-relief islands. We multiplied the maxima for each size class by the number of islands in each size class to predict the number of endemic rails that could have existed in each island group. Numbers in parentheses indicate the number of rails expected for each island size X the number of islands. calculated the proportion of missing endemic species. Our use of maxima reflects the potential lack of fossil data on some islands. For example, well-searched Mangaia of the South Cook Is- lands group held four endemic rails. Tofua of the Tonga Islands, with a similar size and topogra- phy, revealed none. For our estimates we assume that Tofua held four endemic rails. This may be incorrect; to paraphrase Montaigne, speciation is not so often the result of great design as of chance. There may never have been endemic rails on Tofua simply because no rails have sur- vived there long enough to speciate. Since the true number of prehistoric endemics cannot be known, we must be content with es- timating this number by setting realistic limits based on the available data. Of the four factors we consider as aftkcting endemism, we have data on absolute lower island size and distance from source. Data do not exist for two other fac- tors-eftkctive lower island size (disturbance ef- fects) and the minimum distance between is- lands needed to produce endemism (dispersal ef- fects). Thus, we are left with the familiar quan- dary of decreasing our certainty as we increase the number of parameters. We address the prob- lem of prehistoric disturbance on a group by group basis later. Our approach to effective dis- tance between islands is as follows. As noted earlier, we grouped all islands 11 km or closer to each other into sets. While an 11 km expanse of ocean may prohibit the move- ment of a flightless rail, it may have less effect on a strong-flying pigeon. We could further group our islands by diftkrent distances for each taxon, but this would be a series of educated guesses at best. Instead, we approach this prob- lem by determining the maximum number of en- demics that we know to occur in each island group. For example, the Red-bellied Fruit Dove (Ptilinopus greyii) is found on 28 islands of the Vanuatu group (total area of 11,000 km2). Thus, it does not fit our definition of a single-island endemic. It is, however, found only in the Va- nuatu group, so it does exhibit a form of endem- ism. In Vanuatu, this species is found on both low- and high-relief islands. We conclude then that any island group that is dominated by high- relief islands and has a combined area the size of the Vanuatu group would hold an endemic pigeon. We, therefore, produce two estimates for each taxon--the number of endemics at single islands and the number of endemics at island groups. The true number of endemic rails, pigeons, and parrots that have existed in the Pacific probably falls somewhere between these two values. THE BIRDS We chose rails, parrots, and pigeons for our analyses because they are well represented in the fossil record. We reviewed all available litera- ture on the distribution of extant, historically ex- HOW MANY BIRD SPECIES--Curnutt and Pimm 23 TABLE 2. AN ESTIMATE OF THE NUMBER OF RAIL SPE- CIES 1N THE PACIFIC BEFORE HUMAN COLONIZATION Num- Predict- bet of cd total Number spe- number of is cies/is- of spe- Island size and topography lands land cies <600 ha, high and low relief 578 0 0 600-1000 ha, high and low relief 44 1 44 <1000 ha, low relief 61 I 61 1000-6400 ha, high relief 86 2 172 <6400 ha, high relief 65 4 260 Total 834 537 Maximum numbers of species are gleaned from the data for each size/ topography of island. The predicted number of species is the product of maxima and the number of islands. tinct, and subfossil species of these taxa in the Pacific. We assigned each species to all islands on which it was known to occur. RAILS Single-island endemics We catalogued 55 species of rails known to have occurred in the Pacific. Of these, only five (all extant) are not restricted to either single-is- land sets or single-island groups. Two-thirds of the species are known only from fossil data and 65% are endemic to one island. Endemic rails are found on only 13 of the 41 island groups The results of our simulation show that the smallest island with an endemic rail (6.5 km 2) falls within a distribution that has a lower 95% confidence limit of 6 km 2. Both high- and low- relief islands have held single endemic species of rails, thus, we expect that all 256 islands that are larger than 6 km 2 held at least one species. Ten islands, all high relief, held more than one endemic species. The smallest of these was Lord Howe Island (10 km2), which held two species, followed by Mangaia (64 kin2), which held four. Since four species of endemic rails is the max- imum we encountered, we apply this value to all larger islands. Table 2 and Figure 6 illustrate our method of prediction of the number of rail spe- cies for the entire Pacific and specifically for the Hawaiian Island group. We performed the same analysis on each is- land group and estimated that approximately 537 endemic rail species existed in the Pacific, of which 482 are not accounted for by a living or fossil species. Over one-third (36%) of the miss- ing endemics are attributed to only two groups--Vanuatu (94) and Fiji (86). Whereas 13 groups hold no endemics nor are expected to, 14 others hold none but should. Of the remaining 13 groups, 11 hold fewer endemics than ex- pected, and two (Wake Island and Lord Howe Island) hold the number of endemics we predict (one and two, respectively). Island-group endemics Eleven of the 55 species of rails in the Pacific are endemic to groups of islands. The occur- rence of the Wake Island Rail (Rallus wakensis) on Wake Island, an island group in itself, insures the expectation of at least one endemic rail on all low-relief groups except Johnston Atoll, which is too small. For groups with high-relief islands, the maximum number of endemics rang- es from two for groups as small as 10 km 2 (Lord Howe) to 12 for groups larger than 16,700 km 2 (Hawai'i). Summing over all groups, we expect 143 endemic rails in the Pacific based on our island group analysis. PARROTS Single-island endemics Of the 24 species of parrots we catalogued, 9 are endemic to single islands. The majority of these (5) are found in the southwest Pacific. No low-relief islands hold endemic parrots. Norfolk Island (33.7 km 2) represents the smallest island to hold an endemic parrot (Nestor produetus). We estimated that the lower size limit of islands that would support endemic parrots is 28.5 km 2. Excluding the Hawaiian islands and Easter Is- land, there are 110 high-relief islands of 28.5 km 2 or greater. The only island with more than one species of endemic parrot is the largest in our data set--South Island, New Zealand (149,000 km2). Thus, we attribute three species to this island only, for a total of 94 species ([91 islands * 1 species] + [1 island * 3 species]). Island-group endemics In contrast to the rails, a large proportion of parrot species (30%) in the Pacific show endem- ism to single groups of islands. The smallest group to hold an endemic is Norfolk (34 km2), home to Nestor produetus. We apply this value of one endemic to 18 of the 22 island groups that contain high-relief islands. We predicted two endemic parrot species to Vanuatu and Fiji. New Zealand held four endemics. The total number of endemic parrots we expect from our analyses of island groups is a mere 29 species. PIGEONS AND DOVES Single-island endemics We catalogued 43 species of pigeons and doves in the Pacific. Only nine of these are en- demic to single islands. Of these, five are known only from fossil remains and are identified only to genus. Huahine of the Society Islands held the highest number of endemics with three of 24 STUDIES IN AVIAN BIOLOGY NO. 22 the unknown species (Ducula sp., Gallicolumba sp., and Ptilinopus sp.). Henderson Island of the Pitcairn group held two endemics--the extant Henderson Island Fruit Dove (Ptilinopus insu- laris) and a fossil Gallicolumba sp. The remain- ing four endemics were found on Rapa (Rapa Fruit Dove, Ptilinopus huttoni), Mangaia of the South Cook Islands (Gallicolumba sp.), Makatea of the Tuamotu Archipelago (Makatea Fruit Dove, Ptilinopus chalcurus), and Espiritu Santo of the Vanuatu group (Santa Cruz Ground Dove, Gallicolumba sanctaecrucis). The smallest island to hold an endemic was Makatea of the Tuamotu Archipelago. Makatea is 28 km 2 and low relieœ We estimate that the small- est island likely to hold an endemic pigeon or dove would be 20.7 km 2. Islands with more than one endemic are Henderson (36 km 2) with two species and Huahine (75.5 km 2) with three--both of these islands are high relief. Again, excluding Easter Is- land and the Hawaiian groups, our estimate of the total number of enderrfics is thus: (53 islands * 1 species) + (25 islands * 2 species) + (50 islands ß 3 species) = 253 species. Island-group endemics Just as we saw that a greater proportion of parrots showed endemism to groups of islands than the less mobile rails, a full 51% of the pi- geons and doves are restricted to single-island groups compared to 30% for parrots. Thus, there appears to be a positive relationship between flight ability and area over which endemism ex- tends. Vanuatu held the most species (6) of pigeons and doves that were restricted to an island group, and the Marianas held the next highest number (5). These, and the other large groups of islands (Chuuk, Fiji, New Zealand, the Soci- ety Islands, and Tonga) account for 39 of the total 64 species of island-group endemic pigeons and doves. Unlike parrots, endemic pigeons and doves are also found on large low-relief groups. Two species are restricted to the Tuamotu Ar- chipelago, a fact that leads us to predict the same number of species on the Marshall Islands. THE ESTIMATED NUMBER OF ENDEMICS Our exercise produced two sets of estimates of the number of endemic species in each of three taxa. For estimates based on single-island endemism, we predict 537 species of rails, 94 species of parrots, and 253 species of pigeons and doves for a total of 884. We can account for only 57 single-island endemic species of the three taxa as either fossil, extinct or extant. Es- timates based on island-group endemism yield 145 species of rails, 29 species of parrots, and 64 species of pigeons and doves (Fig. 7). We can account for 40 of these as fossil, extinct, or extant. Thus, we predict that the total number of endemic species of these taxa that once occurred in the Pacific falls between 242 and 884. TESTING THE MODELS: KNOWN VERSUS ESTIMATED ENDEMISM We may now investigate factors that would refine our predictions. Which estimates better re- flect the known distribution of endemic rails, parrots, and pigeons and doves in the Pacific-- those derived from single-island endemics or those from island-group endemics? To answer this question, we compare our predicted values with the known distribution of endemic birds. We calculated two indices of the proportion of total missing endemics (all taxa combined) per island group, one for each of our definitions of endemism. We added I to all values of the total number of endemics known to exist and to the totals predicted from our two definitions of endemism. We did this so that we could calcu- late proportions (number of known endemics/ number of predicted endemics) without having zero values in either the numerator or denomi- nator. We arcsine transformed the proportions to make the distribution normal and ranked the re- sults. We then compared the ranks by perform- ing a linear regression of single-island endemic ranks on island-group endemic ranks (Fig. 8). Not surprisingly, the linear fit was significant (F = 18.37, P < 0.01). The slope was less than unity (b = 0.56) suggesting that when the pre- dicted number of endemics corresponds with the actual number of island-group endemics, the sin- gle-island prediction is low and vice versa. We tested for the influence of the number of islands in each group on both of our predictions. Neither set of predictions correlates with this parameter (r < 0.2 for both). Identifying each group as high relief (50% of total area is high relief) or low relief reveals the pattern responsible for the disparity between the two sets of ranks (Fig. 9). Predictions correspond best with known endem- ism for low-relief groups when endemism is de- fined as a single-island distribution. Conversely, for high-relief groups, predictions based on group endemism correspond best with the num- ber of known endemics. We believe there are ecological reasons for this. Groups of low-relief islands tend to have smaller islands than high-relief groups (ANO- VA: F = 4.21, P = 0.04). For low-relief groups, an individual island approach to endemism would successfully identify those few large is- lands in the group that could support a large population of birds. In contrast, predictions based on group endemism would lead to over- estimates because the area across each group is HOW MANY BIRD SPECIES--Curnutt and Pimm 1000 25 800' 600' [] Parrots [] Pigeons [] Rails ß ', 400' E 200' 4--' A B C D FIGURE 7. Total predicted numbers of endemic rails, parrots, and pigeons in the prehistoric Pacific under four sets of assumptions: (A) endemic species are those that occur on only one island; (B) endemic species are those that occur within single-island groups; (C) low-relief island groups produce endemic species at single islands and high-relief island groups produce endemics at island groups; and, (D) the same as (C) with modifications driven by patterns of disturbance (sea-level change and tsunamis). summed. Conversely, the assumption of single- island endemism for the larger islands of high- relief groups ignores factors that potentially lim- it the size of bird communities. In his analysis of the assembly of the fruit-pigeon guild in New Ranked prop. of group endemism FIGURE 8. Ranked proportions of predicted num- bers of endemic birds (rails, parrots, and pigeons com- bined) over known numbers of endemics. Values on the y-axis were generated using the assumption of sin- gle-island endemism while those on the x-axis were generated with the assumption of island-group endem- ism. Guinea, Diamond (1975) showed that the entire species pool is never found in one locality. Some species never occurred together and some sets of species excluded particular species. This ef- fect is primarily due to competition between species with closely related niches. Another eco- logical factor that over inflates the estimates for high-relief islands stems from our grouping across taxa. Some high-relief islands may pro- vide habitat for each of the three taxa we dis- cuss, but it may be unreasonable to assume that all of them do. We can now refine our original estimates of endemism by calculating the totals for each tax- on separately for low- and high-relief island groups using the appropriate assumptions of en- demism (low-relief and single-island endemism; high-relief and island-group endemism). This yields 206 species of rails, 38 species of parrots, and 101 species of pigeons and doves (Fig. 7). These sum to 345 species across taxa. WHERE THE ENDEMICS ARE AND WHERE THEY ARE NOT Five island groups (Johnson Atoll, Howland, South Line, Gambier, and North Cook) are all low relief. They have no endemic species, nor are expected to under the assumption of single- island endemism. Our interpretation of the re- 26 STUDIES IN AVIAN BIOLOGY NO. 22 10' -10 ÷ -2O -3O ß oo o o ß o o ß o o o. o ß ß o ß ß ß o ß ß ß 0 0 ß 0 ß 0 ß ß High-relief Low-relief 0 10 20 30 40 50 Ranked proportion of group endemism FIGURE 9. Residuals of the linear relationship of predicted endemic species under single-island endemism versus island-group endemism (Fig. 8) with each island group defined as either high or low relief. suits for the remaining 36 island groups depends on two assumptions. First, the maximum number of endemics recorded represents the actual max- imum of each taxon that could occur on each type of island and, second, the recorded maxima on each island size/topography are applicable to all islands in each class. There is a chance that the first assumption is incorrect. Continued ex- cavation of subfossil remains may well produce more species of birds, even on islands that are already well represented with endemics. The second assumption ignores differences in the history of islands across the Pacific. While there is little we can do to refine our predictions in light of the uncertainty of the first assumption, we can investigate the history of the Pacific is- lands to uncover patterns of species numbers on island groups. The name "Pacific" belies this ocean's vio- lent history. Natural disturbance of the Pacific islands can be a potentially limiting factor in speciation among birds. Stoddard and Walsh (1992) list five environmental factors that influ- ence island ecosystems: vulcanicity and earth- quakes, sea-level change, tsunamis, rainfall pat- terns, and hurricanes. We investigate two of these: sea-level change and tsunamis. We chose these factors because they operate at regional scales, their effects are unambiguous, and they occur across a temporal scale that is consistent with evolutionary time. SEA-LEVEL CHANGE A number of studies concerning sea-level change in the Pacific over the last 10,000 years have been reported in the literature (Ota et al. 1988, Pirazzoli and Montaggioni 1988, Yonek- ura et al. 1988, Pirazzoli 1991). Throughout the Pacific, sea level was much lower 10,000 years before present (BP) than any time since. At that time, global sea levels were rising rapidly with the melting of the glacial ice sheets. Indeed, the massive infusion of water into the oceans led to regions of hydroisostasy (depression of the ocean floor by water loading) and consequent elevated sea levels (Pirazzoli 1991). Thus, from 6,000 BP to as late as 1,200 BP some island groups had sea levels significantly higher than at present. During the last glacial maximum (18,000 BP), when sea levels were nearly 150 m lower than today, all islands of the Pacific were larger. For example, the Fiji group currently has a com- bined area of 18,600 km 2, whereas at 18,000 BP its area was over 35,000 km 2 (Gibbons and Clu- nie 1986). With rising sea level there would have been a loss of area and habitat. Thus, many island groups probably held more endemic spe- cies in the distant past than they did even in prehistoric times. Isostatic effects have been re- corded for French Polynesia, the South and North Cook Islands, and the Marquesas Islands HOW MANY BIRD SPECIES--Curnutt and Pimm 27 (Pirazzoli and Montaggioni 1988, Yonekura et al. 1988, Stoddard and Walsh 1992; Table 2). As late as 1,200 BP, these groups exhibited less sur- face area than today--with groups such as the Tuamotu Archipelago disappearing almost com- pletely (Gibbons and Clunie 1986). This scenario raises two important consider- ations for our estimates of the prehuman avifau- na. First, the decrease in area of many large is- lands that began at 18,000 BP would have caused a decrease in the number of bird species. This decrease may not have been contemporary with the decrease in area. Diamond (1972) showed that the reduction of one large island, the D'Entrecasteaux Shelf, into a number of small fragments should have led to a reduction of the number of bird species to a new equilib- rium. However, he suggests that the time to reach the new equilibrium is dependent on the size of the new island. Thus, there could be a lag time (of several thousands of years in the above case) before the actual species numbers reflect the restraints of the size of the new island. We are not aware of any studies similar to Di- amond's (1972) that address the islands included in our analyses. We will assume that the avifau- na of the islands was at equilibrium at 4,000 BE In doing so, we risk underestimating the number of species on all islands but those affected by the above mentioned isostatic effect; for these islands, our estimates would be to high. The second consideration regarding sea level and endemism is the effect of elevated sea levels on low-relief islands. The low-relief island groups of Gainbier, North Cook, and the Tua- motu Archipelago were affected by isostatic sea levels (Table 3). Of these, only Tuamotu is ex- pected to have single-island endemics. We pre- dict six species of rails and six species of pi- geons-one pigeon exists (Ptilinopus chalcu- rus). Of this group's 60 islands, only five are greater than 30 km 2. Apparently, this species was able to survive the elevated sea level of 6,000-1,200 BP among these islands. The Fiji group is dominated by large high-relief islands but also holds a large number of surrounding low-relief islands. This group experienced sea levels nearly 2 m higher than present as late as 2,500 BP (Gibbons and Clunie 1986). Endem- ism would have been improbable in these is- lands up to that time because of the lower extent of the area. We predict that eight species of pi- geons and 16 species of rails could have inhab- ited these low islands--none are known to have existed there. We removed the low-relief islands from the total area and calculated the number of endemic species we would expect on Fiji based on group endemism. This had no effect on our predictions. The size of Fiji's high-relief islands TABLE 3. ISLAND GROUPS FOR WHICH PUBLISHED DATA EXIST ON MEAN SEA LEVELS (RELATIVE TO PRESENT; IN METERS) AT THREE PERIODS OF THE HOLOCENE (FROM PIRAZZOLI 1991); MAXIMUM SEA LEVEL AND TIME OF OC- CURRENCE (OTA ET AL. 1988, PIRAZZOLI AND MONTAG- GION! 1988, YONEKURA ET AL. 1988, PIRAZZOLI 1991); AND MAXIMUM TSUNAMI RUN-UP HEIGHT (NATIONAL GEO- LOGIC DATA CENTER) Group Mean relive sea level Years before present x 10 3 Maxi- Maximum mum 10 5 2.5 sea level run-up Melanesia Vanuatu Fiji Micronesia Palau Yap Chuuk Marianas Pohnpei MarshalIs Gilbert Polynesia Hawai 'i North Line Tuvalu Samoa Norda Cook Tonga South Cook Marquesas Society Tuamotu Gainbier Pitcairn Rapa Tabuai Kermadec Norfolk New Zea- land Chatham + 1 0 2 (2500) -40 -2 - 1 +4.5 +2.4 -40 -5 -2 +2.4 -3 +2.4 >-15 0 0 +0.6 5 -2 -17 -1 +1 >-20 +0.5 +1 > 20 +0.9 +0.9 0 5.9 0 1.9 1.9 0 16.8 0 1.9 1 (1500) 0 0 1.7 (3400) 0 1 (1500) 9 1 (1500) 3.4 1 (1200) 2.3 1 (1500) 0 1 (1500) 1.8 1 (1500) 0 12 0 0 5.9 0 0 are near the maximum for the Pacific, and the removal of the low-relief islands did not lead to a change of the maximum number of species expected. Johnson et al. (1996), investigating the evo- lution of cichlid fish, reported the most rapid vertebrate speciation known--on the order of 3,000 years. Thus, high sea levels up to 1,200 BP must have reduced bird speciation on some Pacific islands. The eflbct of our sea-level anal- yses on our predictions results in the removal of five species of pigeons and six species of rails from our total. TSUNAMIS Tsunamis are a series of high-energy waves propagated by a major displacement of earth un- 28 STUDIES IN AVIAN BIOLOGY NO. 22 FIGURE 10. Areas affected by tsunamis (shaded) and the direction of tsunamis arrows) in the Pacific from 1900 to 1983 as reported in the Worldwide Tsunami Database (Lockridge and Smith 1984). der the sea. They can have devastating effects on islands. For example, in the early morning hours of I April 1946 an earthquake in the Aleu- tian Islands, Alaska, caused a tsunami. Within minutes a manned lighthouse on Unimak Island had been obliterated with all hands lost. Four and a half hours later and over 3,000 km away the same tsunami hit the Hawaiian Islands. Reaching a maximum run-up height of nearly 17 m, it smashed into the Island of Hawai'i taking another 241 lives. This same series of waves caused casualties and property damage in Cali- fornia and as far south as central Chile (Lock- ridge and Smith 1984, Myles 1985). Tsunamis of this magnitude are frequent with 14 occurrences in the Pacific Basin from 1900 to 1983 (Lockridge and Smith 1984). As with sea-level change, the effect of tsunamis on is- lands is variable. Islands without surrounding submarine shelves are more susceptible to re- motely generated tsunamis because there is little to absorb the energy of the waves before they make contact. Topography and elevation above sea level are also obvious factors in determining the effect of tsunamis on islands. We accessed the Worldwide Tsunami Data- base, compiled by the National Geologic Data Center (http ://j ulius.ngdc.noaa.gov/seg/hazard/ tsudb.html), for recorded occurrences of tsuna- mis within our study site. Uninhabited islands are not well represented in the data set. For each occurrence we noted the location of the tsunami, its maximum run-up height, and its point of or- igin. We then classified our island groups as ei- ther susceptible to tsunamis or unaffected (Table 3). The earliest recorded tsunami in our study area occurred in 1843. Since then over 130 tsu- namis have been recorded. The Hawaiian Is- lands have seen the most tsunamis, a result of their central location relative to areas of seismic activity around the Pacific Rim and the lack of any energy-absorbing shelves around the group. Figure 10 shows regions affected by tsunamis and, when known, the direction traveled by tsu- namis from their point sources. HOW MANY BiRD SPECIES--Curnutt and Pimm 29 We have data on tsunamis for 21 of our 41 island groups. Ten of these, however, have max- imum recorded run-up heights of zero. That is, tsunami events do not noticeably affect these groups. Many of these fortunate island groups are low relief, including the extensive Marshall Islands. Ten of the remaining eleven groups are high relief and have experienced run-up heights from less than 2.0 to 16.8 m. The sole low-relief group affected by tsunamis is the Tuamotu Ar- chipelago with a maximum run-up of 2.3 m. The disturbance caused by tsunamis on high- relief islands is primarily limited to coastal ar- eas, below the altitudinal distribution of most of the species we are concerned with. The effect of tsunamis on the fauna of the Tuamotu Archipel- ago, however, could be devastating. Most of the islands of this group are only a few meters in elevation, and the combined effect of higher sea level during the mid- and late-Holocene with tsunamis helps explain why this group has fewer endemics than we predict based on its size and topography. Finally, the Tonga group experi- enced a maximum run-up height of 4.0 to 6.0 m. This group is dominated by high-relief is- lands; however, 193 kul 2 of its total 563 km 2 consists of low-relief islands. Assuming tsuna- mis were frequent and devastating enough to prevent endemism on these low islands, we can calculate a refined estimate of the number of en- demics for this group by excluding all low-relief islands. This exercise results in the loss of one species of rail and one species of pigeon, leaving 35 rails, 12 pigeons, and 4 parrots attributed to the Tonga group. Combining the effects of sea-level change and tsunamis, we can refine our previous estimate of predicted endemic species in the Pacific as fol- lows: 199 endemic rails, 38 endemic parrots, and 95 endemic pigeons and doves (Fig. 7). PROBLEM GROUPS Even after incorporating the above adjust- ments to our predicted numbers of species, ac- tual species account for less than half of the pre- dicted numbers for 13 of the 23 high-relief groups. Six groups (Rotuma, Tabuai, Wallis and Futuna, Yap, Tonga, and Kermadec) have no ac- tual island-group endemics although we predict from two to five species for these groups. For low-relief groups, 10 (Nauru, Northwest Ha- wai'i, Tokelau, Tuvalu, Gilbert, Niue, Phoenix, Chuuk, Marshall Islands, North Line Islands) have no actual single-island endemics although we predict from 1 to 20 species for these groups. In all, we predicted 210 species of rails, pigeons, and parrots that are not accounted for as either fossil, extinct, or extant. DISCUSSION We estimate that there were approximately 330 species of rails, pigeons, and parrots on the islands of the Pacific before human colonization began 4,000 years ago. Approximately one-third of these species are accounted for as either ex- tant, historically extinct, or as fossils. Pimm et al. (1994), who looked for all landbirds, pre- dicted that the fossil record was only half com- plete and that the original avifauna was about 800 species. In reviewing the fossil, historical, and current data, we could account for only one- third of the estimated number of species in the taxa we looked at. We should therefore apply a three-fold correction to the total number of known landbirds (540) and conclude that the en- tire Pacific landbird fauna was comprised of 1,620 or so species before human colonization. This simple multiplication, however, ignores dif- ferences in extinction rates between taxa. Stead- man (1997a,b) suggested that flightless rails suf- fered a greater proportion of extinctions than any other taxon of birds. If so, an estimate of 1,500 species would be too high. In comparing our results to Steadman's (1995) estimates, we must limit our consideration to rails--the only taxon that Steadman makes a quantitative estimate of. We estimate that the prehuman Pacific held about 200 species of rails, of which 21 are extant. Steadman's (1995) esti- mate (2,000+ species of rails) is an order of magnitude greater than ours. Like Steadman, we based our analyses on the roughly 800 larger islands of the Pacific. However, where Steadman simply multiplied a maximum number of rails per island by the number of islands, we incor- porated into our analyses statistical probabilities and geographical, topographical and environ- mental data. Thus, we believe that Steadman's (1995) estimate of the prehuman avifauna is too high. More fieldwork will inevitably bring new data to light. The discovery of more fossil species will potentially alter our estimates because of the multiplicative nature of our analyses. The dis- covery of one new fossil rail on a small island could conceivably add 800 to our current esti- mate of 200. This would still be half as much as the highest proposed number of rails (Stead- man 1995). Currently, we suggest that the pre- human avifauna consisted of more than 800 and less than 1,500 species of landbirds. Further re- search (as outlined below) is needed to refine our estimates and to conserve the remaining spe- cies of the Pacific islands. CONSERVATION CONCERNS The loss to extinction of even our lowest pre- dicted number of endemic species is disturbing. 30 STUDIES IN AVIAN BIOLOGY NO. 22 Much more disturbing is the potential effect of this prehistoric loss on the biodiversity of the future. Habitat loss and the introduction of ex- otic species have had profound negative effects on endemic Pacific landbirds (Atkinson 1985, Pimm 1987). For rails, some of the progenitors of the clan of now extinct endemics may have themselves become extinct and anthropogenic disturbance on many islands may make recolon- ization by extant rails impossible. Thus, even for a rapidly speciating taxon like flightless rails, the potential for diversity has been greatly dimin- ished. Another conservation concern for Pacific landbirds is the rise of global sea levels. Al- though predictions of the rate of sea-level rise are rife with uncertainty, it is clear that global warming and subsequent rises in sea level will occur for centuries into the future (Hutter et al. 1990). Even with a moderate estimate of 4 to 6 cm per decade (Hutter et al. 1990, Wigley and Raper 1993) many low-relief islands will be in- undated within the next few centuries. FUTURE RESEARCH OPPORTUNITIES Our predictions of the prehistoric Pacific is- land avifauna are testable. Using our results, re- searchers can focus excavation efforts on those islands that we predict will hold fossils of the greatest number of extinct species. Thus, we provide our analyses and results as a guide for continued work in this area of biodiversity. We conclude with the following suggestions for fur- ther study: Where to look for subfossil birds We predict that the greatest number of extinct landbirds existed on high-relief islands of at least I km 2 in size. The greatest part of the "missing" rails are from Fiji and Vanuatu. These areas should be surveyed intensely for subfossil remains. Searches should, perhaps, also include island shelves that are currently submerged. Gibbons and Clunie (1986) make a strong argument for extending archeological ex- cavations to these areas because they were ex- posed and possibly colonized during the human expansion into the Pacific. Analyze the loss of potential species richness A thorough understanding of the phylogenetic relationship between the landbird species of the Pacific would serve to identify the mechanisms of speciation and the ancestral species that most contribute to the potential diversity of each tax- on. A molecular genetic analysis and mapping of the relationship of these species may also un- cover phylogenetic differences in speciation rates, dispersal, and habitat utilization. Predict the ef/kcts of rising sea level on current bird diversity We have described the effect of area and to- pography on bird species diversity. Currently, models are available that predict changes in sea level both globally and regionally (Wigley and Raper 1993). The application of sea-level change projections to Pacific islands would re- sult in predicted size distributions of islands, to which our approach can be applied. This will allow us to predict the expected loss of bird spe- cies in the Pacific in the coming century. These analyses, coupled with more traditional efforts (e.g., Franklin and Steadman 1991) could also be used to map a survival strategy for Pacific biodiversity in light of the threat of future sea- level rise. ACKNOWLEDGMENTS We thank M. Moulton, D. Steadman, K. Reese, R. Walker, S. Conant, and one anonymous reviewer for their comments. SLP thanks the Pew Fellowship in Conservation and the Environment for support. Studies in Avian Biology No. 22:31-46, 2001. PATTERNS OF SUCCESS AMONG INTRODUCED BIRDS IN THE HAWAIIAN ISLANDS MICHAEL P. MOULTON, KARL E. MILLER, AND ERIC A. TILLMAN Abstract. At least 140 species of 14 different orders of birds have been introduced to the six main Hawaiian Islands. The introduced species came from six continents and the introductions were carried out by a variety of agents including state and local governments, private citizens, and the acclimati- zation society known as the Hui Manu. The introductions mostly occurred during the early to mid- twentieth century. Most (79%) of the intentional introductions were of species from three orders: Galliformes, Columbiformes, and Passeriformes. Introduction success rates were significantly greater for passeriforms than for either columbiforms or galliforms, although the reasons for this are unknown. In predicting the fate of future introductions, only the columbiforms showed an "all-or-none" pattern of introduction history. Successful species had larger native geographic ranges than did unsuccessful species, which supports the hypothesis that range size is correlated with the ability to adapt to a new environment. Finally, in a partial test of the introduction effort hypothesis we found that galliforms successfully introduced to the island of Hawai'i were introduced in significantly larger numbers than unsuccessful species. Key Words: doves; game birds; introduced species; introduction effort; introduction success; native range size; perching birds; pigeons. Numerous species of birds from six continents have been introduced to the Hawaiian Islands (Caum 1933, Berger 1981, Long 1981, Pratt et al. 1987). These species were introduced by a variety of groups for a variety of reasons. As noted by Berger (1981), the first avian introduction came with early Polynesians who brought the Red Jun- glefowl (Gallus gallus) for food. Since that time, a number of private citizens have brought species to Hawai'i (e.g., Caum 1933). Some of these in- troductions were made inadvertently as individual birds escaped captivity (e.g., Melodious Laughing- thrush or Hwamei, Garrulax canorus, on O'ahu), whereas others were intentionally released for aes- thetic reasons or even as an attempt at biological control (Caum 1933). There also have been inten- sive efforts both by private citizens (e.g., Lewin 1971) as well as state and county agencies (Schwartz and Schwartz 1949; Walker 1966, 1967) to establish populations of various game birds for recreational hunting. In the early to mid-twentieth century, the acclimatization society known as the Hui Manu actively introduced several species to various islands (Caum 1933, Berger 1981). Regardless of their source, a central question in any study of introduced birds is "Why do some species succeed and others fail?" In sev- eral papers we and our colleagues have argued that competition has played an influential role in determining the outcomes of passerine species' introductions in Hawai'i (Moulton and Pimm 1983, 1986a, 1987; Moulton 1985, 1993; Moun- tainspring and Scott 1985; Moulton et al. 1990; Moulton and Lockwood 1992). These arguments are based on three main findings. First, intro- ductions tend to be less successful when more species of introduced birds are already present (Moulton 1993; Moulton and Pimm 1983, 1986a). Second, there is a pattern of limiting similarity among congeneric pairs of introduced birds: differences in bill length are significantly greater in pairs that coexist than in pairs of spe- cies that were not able to coexist (Moulton 1985). And third, successful introduced passer- ines show a pattern of morphological overdis- persion (Moulton and Pimm 1987, Moulton and Lockwood 1992); i.e., successful species are morphologically more different from each other than expected by chance. Although these three patterns are consistent with predictions from competition theory, other explanations for patterns in introduction out- comes have been advanced. These include intro- duction history of a species (Simberloff and Boecklen 1991) and introduction effort (e.g., Pimm 1991, Veltman et al. 1996). The idea that introduction history can predict future introduction outcomes is appealing in its simplicity. The concept comes from Simberloff and Boecklen (1991) who argued that whenever and wherever a given species is introduced, it tends to either always succeed or always fail. This leads to an "all-or-none" pattern in the dis- tribution of birds introduced onto a series of is- lands: some species being successful on "all" the islands in the series and others being suc- cessful on "none" of the islands. If introduced birds actually follow this pattern, then predicting the outcome of future introductions would be greatly simplified. Moulton (1993) and Moulton and Sanderson (1997), however, argued that the all-or-none pattern reported by Simberloff and Boecklen (1991) for passerine birds was pri- marily an artifact of sample size. 31 32 STUDIES IN AVIAN BIOLOGY NO. 22 Another factor that might influence the out- come of introductions is the effort invested in the introduction process. Griffith et al. (1989) found that introduction effort along with habitat quality were associated with introduction out- come. Similarly, Pimm (1991 ) studied introduc- tions of seven game bird species (all of which had been successfully introduced somewhere in the world) in the western United States and found that there was a very high (360/424 = 85%) failure rate. Pimm's analysis indicated that the failure rate was particularly high when fewer tha