The bridled white-eye (''Zosterops conspicillatus'') ( Chamorro name: ''nosa'') is a species of

white-eye The white-eyes are a family, Zosteropidae, of small passerine birds native to tropical, subtropical and temperate Sub-Saharan Africa, southern and eastern Asia, and Australasia. White-eyes inhabit most tropical islands in the Indian Ocean, ...

native to the

Mariana Islands The Mariana Islands ( ; ), also simply the Marianas, are a crescent-shaped archipelago comprising the summits of fifteen longitudinally oriented, mostly dormant volcanic mountains in the northwestern Pacific Ocean, between the 12th and 21st pa ...

and formerly

Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...

. The species' natural

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

is tropical forests, shrublands and urban areas.

Taxonomy

Some sources, such as the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

, split the nominate subspecies and ''Z. c. saypani'' into separate species; in that case, the latter is known by the common name Saipan white-eye. Formerly, the

Rota white-eye The Rota white-eye or Rota bridled white-eye (''Zosterops rotensis'') is a species of bird in the family Zosteropidae. It is critically endangered and endemic to Rota in the Northern Mariana Islands, where it mainly occurs in mature, wet limesto ...

(''Zosterops rotensis'') was also considered as a subspecies of the bridled white-eye.

Conservation

The nominate subspecies ''Zosterops conspicillatus conspicillatus'',

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the island of Guam, became

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

due to the introduction of the

brown tree snake The brown tree snake (''Boiga irregularis''), also known as the brown catsnake, is an arboreal rear-fanged colubrid snake native to eastern and northern coastal Australia, eastern Indonesia (Sulawesi to Papua), Papua New Guinea, and many island ...

. The last known sighting was in 1983. The

US Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is a U.S. federal government agency within the United States Department of the Interior which oversees the management of fish, wildlife, and natural habitats in the United States. ...

delisted the species from the

Endangered Species Act The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...

in October 2023 citing extinction. The remaining subspecies, ''Z. conspicillatus saypani'', endemic to the

Northern Mariana Islands The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands (CNMI), is an Territories of the United States, unincorporated territory and Commonwealth (U.S. insular area), commonwealth of the United States consistin ...

, on the islands of

Tinian Tinian () is one of the three principal islands of the Commonwealth of the Northern Mariana Islands (CNMI). Together with uninhabited neighboring Aguiguan, it forms Tinian Municipality, one of the four constituent municipalities of the Northern ...

Saipan Saipan () is the largest island and capital of the Northern Mariana Islands, an unincorporated Territories of the United States, territory of the United States in the western Pacific Ocean. According to 2020 estimates by the United States Cens ...

and

Aguijan Aguijan (; ; also Aguiguan and Aguihan, based on the Spanish rendition of the native name) is a small bean-shaped uninhabited coralline island in the Northern Mariana Islands chain in the Pacific Ocean. It is situated south-west of Tinian, from ...

, is separated as a full species by some authorities, in which case its common name is Saipan white-eye. This population is extremely abundant across its native range. 2007-2008 surveys estimated a population of 620,000-940,000, with approximately 534,000 birds on Saipan alone. In 2010, this species was the second most abundant breeding landbird encountered by surveyors on Saipan. As of 2022, the population was believed to not have changed significantly since earlier surveys and it was considered stable. In 2008, ''Z. c. saypani'' was also introduced to the uninhabited island of

Sarigan Sarigan or Sariguan is an uninhabited volcanic island in the Pacific Ocean. It is part of the Northern Mariana Islands, a U.S. territory. Sarigan is located northeast of Anatahan island, south of Guguan and north of Saipan, the largest isla ...

as a precaution and by 2016 this new population had rapidly increased to more than 8,000 birds. The potential introduction of the brown tree snake on Saipan and

U.S. military The United States Armed Forces are the military forces of the United States. U.S. federal law names six armed forces: the Army, Marine Corps, Navy, Air Force, Space Force, and the Coast Guard. Since 1949, all of the armed forces, except th ...

activity on Tinian could result in rapid population declines on these islands, but biosecurity measures to reduce this risk have so far been successful. If a brown treesnake still manages to enter the islands, a specially trained and equipped response team is deployed to eliminate it, reducing the risk of a new population becoming established. As a precautionary measure, the Saipan white-eye has been classified as

near threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...

. The Saipan white-eye has a

captive breeding program Captive breeding, also known as captive propagation, is the process of keeping plants or animals in controlled environments, such as wildlife reserves, zoos, botanic gardens, and other conservation facilities. It is sometimes employed to help sp ...

based at several US zoos.

References

bridled white-eye The bridled white-eye (''Zosterops conspicillatus'') ( Chamorro name: ''nosa'') is a species of white-eye native to the Mariana Islands and formerly Guam. The species' natural habitat is tropical forests, shrublands and urban areas. Taxonomy Som ...

Birds of the Northern Mariana Islands

Taxa named by Heinrich von Kittlitz Taxonomy articles created by Polbot {{Zosteropidae-stub

Taxonomy

Conservation

See also

References