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
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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