The Eiao Polynesian Warbler (Acrocephalus caffer aquilonis) is a subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of the Polynesian Warbler found only in the dry upland forest

Forest

A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

 on Eiao

Eiao

Eiao is the largest of the extreme northwestern Marquesas Islands. The island was discovered in 1791 by the American navigator Joseph Ingraham, who named it Knox Island in honor of the then-current United States Secretary of War, Henry Knox...

 in the northern Marquesas Islands

Marquesas Islands

The Marquesas Islands enana and Te Fenua `Enata , both meaning "The Land of Men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in the southern Pacific Ocean. The Marquesas are located at 9° 00S, 139° 30W...

.

The species comprises several different races, each of which occupies a variety of forest or bush

The Bush

"The bush" is a term used for rural, undeveloped land or country areas in certain countries.-Australia:The term is iconic in Australia. In reference to the landscape, "bush" describes a wooded area, intermediate between a shrubland and a forest, generally of dry and nitrogen-poor soil, mostly...

land habitats.
Because of extensive habitat destruction by feral

Feral

A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...

 goat

Goat

The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...

s, sheep and pig

Pig

A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

s, the species is endangered

Endangered species

An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

, and may very well be extinct.

The total population was estimated at approximately 100-200 individuals in 1987.