Center for Biological Diversity

Endangered Bird Trends

Far Pacific  

ESA Population Trend Determined:

 

Aguiguan nightingale reed-warbler, or gaga karisu

AGUIGUAN NIGHTINGALE REED-WARBLER, OR GAGA KARISU (Acrocephalus luscinia nijoi)

Aguiguan nightingale reed-warbler, or gaga karisu
Aguiguan nightingale reed-warbler, or gaga karisu population graph

Status since listing: Declined

Growth since listing: -100%

ESA status: Endangered

List year: 1970

Recovery plan: 1998

SUMMARY
The Aguiguan nightingale reed-warbler, or gaga karisu, was endemic to dense native forest understories on the island of Aguiguan in the Northern Mariana Islands. Prior to 1945, much of its habitat was destroyed or degraded by farming and development. After being listed as endangered in 1970, it was only seen a few times, with the last sighting in 1995. The bird was not found during targeted surveys in the 2000s and is likely extinct.

Guam kingfisher, or sihek

GUAM KINGFISHER, OR SIHEK (Todiramphus cinnamominus)

Guam kingfisher, or sihek
black-capped vireo, Vireo atricapilla, population graph

Status since listing: Declined

Growth since listing: -100%

ESA status: Endangered

List year: 1984

Recovery plan: 2008

Critical habitat: 1994

SUMMARY
The Guam kingfisher, or sihek, was extirpated from the wild by the logging and clearing of Guam's native forests and the introduction of invasive ungulates and predatory brown tree snakes which grew to extraordinary densities. In 1981, 502 birds were observed and 3,023 were estimated to exist. By 1985, the year after it was listed as endangered, just 30 birds were detected. It was extirpated by 1988. The captive population increased from 26 birds in 1984, to 155 in 2011.

Guam rail, or ‘ko‘ko

GUAM RAIL, OR 'KO'KO (Rallus owstoni)

Guam rail, or ‘ko‘ko
Guam rail, or ‘ko‘ko population graph

Status since listing: Increased

Growth since listing: 650%

ESA status: Endangered

List year: 1984

Recovery plan: 1990

SUMMARY
The Guam rail, or ‘ko‘ko, is threatened by predation by brown tree snakes, feral cats and other introduced species. The rail declined catastrophically between 1968 and 1983 as brown tree snakes spread across the island. Only 20 wild birds were estimated when the species was listed in 1984. It was extirpated from the wild in 1985. A captive population grew from 21 in 1983 to 170 in 2014, and wild populations created in 1989 and 2010 numbered 150 as of 2014.

Mariana crow, or aga

MARIANA CROW, OR AGA (Corvus kubaryi)

Mariana crow, or aga
Mariana crow, or aga,Corvus kubaryi, population graph

Status since listing: Declined

Growth since listing: -93%

ESA status: Endangered

List year: 1984

Recovery plan: 2005

Critical habitat: 1994

SUMMARY
The Mariana crow, or aga, is endemic to Guam and Rota. Its population has declined due to habitat destruction by agriculture, urban and military development, hunting, and predation by invasive brown tree snakes and feral cats. It was common on Guam through the 1940s, declined substantially by the 1960s, and was extirpated in 2013. On Rota, it declined from 1,491 birds in 1982 to 101 in 2014. Rangewide it declined from 1,666 birds in 1983 to 101 in 2014.

Mariana mallard

MARIANA MALLARD (Anas oustaleti)

Mariana mallard
Mariana mallard, Anas oustaleti, population graph

Status since listing: Declined

Growth since listing: -100%

ESA status: Delisted

List year: 1977

Delisted: Final 2004

SUMMARY
The Mariana mallard was likely never common due to the limited extent of wetlands on the Mariana Islands. It was driven extinct by the draining and filling of wetlands around WWII. Pollution, hunting, and egg/specimen collection were also factors. The bird was extirpated from Guam (1967) and Tinian (1974) prior to being listed as endangered in 1977. The last three birds were captured in a 1979 emergency rescue. A male was released and never seen again. The others died in captivity in 1981.

Mariana nightingale reed-warbler subspecies, or ga kaliso / gaga karisu

MARIANA NIGHTINGALE REED-WARBLER SUBSPECIES, OR GA KALISO / GAGA KARISU (Acrocephalus luscinia luscinia)

Mariana nightingale reed-warbler subspecies, or ga kaliso / gaga karisu
Mariana nightingale reed-warbler subspecies, or ga kaliso / gaga karisu,Acrocephalus luscinia luscinia, population graph

Status since listing: Declined

Growth since listing: -42%

ESA status: Endangered

List year: 1970

Recovery plan: 1998

SUMMARY
The Mariana nightingale reed-warbler subspecies, locally named ga kaliso or gaga karisu, has been threatened mainly due to habitat loss. Causes include fire and wetland conversion. The bird was extirpated on Guam in 1969, the year before it was listed as endangered. Combined numbers from Alamagan and Saipan declined from 8,008 in 1986 to 4,634 in 2009.

Mariana swiftlet, or yayaguak

MARIANA SWIFTLET, OR YAYAGUAK (Aerodramus bartschi)

Mariana swiftlet, or yayaguak
population graph for Mariana swiftlet, or yayaguak, Aerodramus bartschi

Status since listing: Increased

Growth since listing: 61%

ESA status: Endangered

List year: 1984

Recovery plan: 1991

SUMMARY
The Mariana swiftlet, or yayaguak, is not well studied, and the causes of its decline are not well known, but they appear to include nest-site disturbance, habitat loss and brown tree snake predation. While not uniform across the islands inhabited by the subspecies, overall the rangewide population had increased from about 4,180 birds in 1984 to about 6,750 as of 2015.

Mariana common moorhen, or pulattat

MARIANA COMMON MOORHEN, OR PULATTAT (Gallinula chloropus guami)

population graph for Mariana common moorhen, or pulattat, Gallinula chloropus guami

Status since listing: Stable

Growth since listing: -18%

ESA status: Endangered

List year: 1984

Recovery plan: 1991

SUMMARY
The Mariana common moorhen, or pulattat, declined on the four small Mariana islands to which it is endemic due to the draining, filling, degradation and pollution of wetlands, hunting, and predation by invasive species. Some island populations increased and other decreased since it was listed as endangered in 1984, but overall it was stable with the population estimated at 312 in 1984, 350 in 1990, 287 in 2001, and 285 in 2014.

Micronesian megapode

MICRONESIAN MEGAPODE (Megapodius laperouse)

Micronesian megapode
Micronesian megapode, Megapodius laperouse, population graph

Status since listing: Increased

Growth since listing: 323%

ESA status: Endangered

List year: 1970

Recovery plan: 1998

SUMMARY
The Micronesian megapode has been threatened by habitat loss, fragmentation, and degradation by development and navy training exercises, and by hunting, and the effects of feral, dogs, cats and pigs. While megapode populations are increasing on certain islands, they are stable or decreasing on others. Overall the species increased from 2,587 birds in 1986 to 10,935 in 2010, although some of the growth was due to increased survey effort.

Palau fantail

PALAU FANTAIL (Rhipidura lepida)

Palau fantail
Palau fantail population graph

Status since listing: Unknown

Growth since listing: Unknown

ESA status: Delisted

List year: 1970

Delisted: Final 1985

SUMMARY
The Palau fantail was driven to near extinction by World War II military operations which destroyed or degraded most of its habitat. It was listed as an endangered species in 1970, rebounded and was delisted in 1985. Its trend-since-listing is unknown as there are no population estimates in that time period.  In 1991, it was estimated at 27,154 birds, in 2015 was abundant or common on most of Palau's islands, and in 2016 was considered to be increasing.

Palau ground dove

PALAU GROUND DOVE (Gallicolumba canifrons)

Palau ground dove population graph

Status since listing: Stable

Growth since listing: 0%

ESA status: Delisted

List year: 1970

Delisted: Final 1985

SUMMARY
The Palau ground dove was nearly driven extinct by habitat-destroying military operations during World War II. It is currently at risk from the potential introduction of invasive predators, including rats and brown tree snakes. Its population was unquantified but very small in 1945. It was listed as endangered in 1970 and remained stable at about 500 birds between 1978 and 1985, when it was delisted due to recovery. A 2012 population estimate of at least 600 is uncertain.

Palau owl

PALAU OWL (Pyroglaux podargina)

Palau owl population graph

Status since listing: Unknown

Growth since listing: Unknown

ESA status: Delisted

List year: 1970

Delisted: Final 1985

SUMMARY
The Palau owl is endemic to the islands of Palau. It was nearly eliminated by forest destruction during World War II and the introduction of invasive rhinoceros beetles, supposedly capable of eviscerating the owl from the inside upon being swallowed. The species was at very low numbers in 1945 and into the late 1960s. It was listed in 1970 and had increased to 12,000 individuals by 1978 due to forest recovery and beetle control. The owl was delisted in 1985.

Rota bridled white-eye

ROTA BRIDLED WHITE-EYE (Zosterops rotensis)

Rota bridled white-eye
Rota bridled white-eye population graph

Status since listing: Increased

Growth since listing: 88%

ESA status: Endangered

List year: 2004

Recovery plan: 2007

Critical habitat: 2006

SUMMARY
The Rota bridled white-eye is endemic to the island of Rota, where it has declined significantly in range extent and population size due to predation from introduced species and other factors not yet known. Formerly common, the bird declined to a population of 14,963 in 1982 and a low of 2,015 in 1995. It was listed as endangered in 2004 and its population increased from 6,591 in 2003 to 9,730 in 2006, then to 14,384 in 2012.

Tinian monarch, or Chickurikan Tinian

TINIAN MONARCH, CHICKURIKAN TINIAN (Monarcha takatsukasae)

Tinian monarch, or Chickurikan Tinian
population graph for Tinian monarch, or Chickurikan Tinian, Monarcha takatsukasae

Status since listing: Stable

Growth since listing: 10%

ESA status: Delisted

List year: 1970

Downlisted: Final 1987

Delisted: Final 2004

SUMMARY
The population of the Tinian monarch, or Chickurikan Tinian, reached critically low levels due to the removal of native forests for sugarcane production prior to World War II and military activities during the war. The species continues to face numerous threats. After its listing in 1970, numbers reached 95,916 in 1982 and 105,352 in 1996. The monarch was delisted in 2004. During listing its population remained stable. In 2013, population estimates stood at 90,634.

Extinct or Extirpated Prior to ESA Listing:

 

Guam bridled white-eye, or nossa

GUAM BRIDLED WHITE-EYE, OR NOSA (Zosterops conspicillatus conspicillatus)

Guam bridled white-eye, or nossa
population graph for Guam bridled white-eye, or nossa, Zosterops conspicillatus conspicillatus

ESA status: Endangered

List year: 1984

Delisted: Five-year review 2009

Recovery plan: 1990

Critical habitat: 1994

SUMMARY
The Guam bridled white-eye, or nosa, was driven extinct by the brown tree snake, which invaded the island and vastly proliferated, driving all but two of Guam's native birds extinct by preying upon eggs, nestlings and adults. Formerly the most common bird on its island, it was reduced to an estimated 2,220 individuals in 1981 and last seen in 1983. It was listed as endangered in 1984 in the hope that it would be rediscovered, but it hasn't been seen despite subsequent surveys.

Guam broadbill, or chuguangguang

GUAM BROADBILL, OR CHUGUANGGUANG (Myiagra freycineti)

Guam broadbill
Guam broadbill population graph

Recovery plan: 1990

Critical habitat: 1994

ESA status: Delisted

List year: 1984

Delisted: Final 2004

SUMMARY
The Guam broadbill, or chuguangguang, was driven extinct by disease, pesticides and predation by invasive species, the most important of which was the ubiquitous brown tree snake. Its range declined from 310 square miles in 1900, to 193 in 1950, and 0.6 in 1983. Its population declined from 460 estimated birds in 1981, to less than 100 in 1983. Only two birds were seen in 1984 and none after. It was listed as endangered in 1984.

Pagan nightingale reed-warbler

PAGAN NIGHTINGALE REED WARBLER, OR GAGA KARISU (Acrocephalus luscinia yamashinae)

ESA status: Endangered

List year: 1967

Recovery plan: 2006

SUMMARY
The Pagan nightingale reed-warbler, or gaga karisu, was threatened mainly by the clearing and subsequent grazing of much of its habitat. As of the 1960s, the bird has not been seen despite multiple survey efforts made in hopes of detecting the subspecies.