The Bird's Neck Isthmus is an isthmus in western New Guinea. It connects the main mass of the island to its two large western peninsulas, the Bird's Head Peninsula, also known as the Vogelkop or Doberai Peninsula, and the Bomberai Peninsula. The isthmus is mostly covered in lowland tropical rain forest. [1]
The isthmus is bounded by Cenderawasih Bay to the north, and the Arafura Sea to the south. The drainage divide is considerably closer to the north shore than to the south shore. The mountainous Wandammen Peninsula projects northwards from the isthmus into Cenderawasih Bay. Etna Bay, Triton Bay, and Arguni Bay are located on the southern coast of the isthmus, and Arguni Bay separates the isthmus from the Bomberai Peninsula. [2]
Most of isthmus' terrain consists of ridges and valleys running north-northwest to west-northwest. This geologic region, whose surface rocks are mostly limestone, is known as the Lengguru Fold and Thrust Belt. This belt is approximately 300 km in length, and ranges from 30 km wide at its northern end to 100 km in width along the southern shore of the isthmus. The folding and faulting of the earth's crust which formed the belt began about 5 million years ago. The Lengguru Fold and Thrust Belt is bounded on the east by the Wandammen Ridge, which is composed of older (Paleozoic and Mesozoic) sedimentary and metamorphic rocks. To the west the fold and thrust belt transitions to the Bintuni Basin lowlands, which underlie most of the Bomberai Peninsula. [3]
The isthmus includes a gap in the chain of mountains that run almost continuously down the length of the island from the Bird's Head Peninsula to New Guinea's southeastern tip. This gap, known as the Omba-Woromi corridor, extends along the eastern side of the fold and thrust belt, and is about 60 km wide with a maximum elevation of only 160 metres. It separates the Weyland Mountains, the westernmost portion of New Guinea's Central Range, from the uplands of the isthmus and the western peninsulas. Lake Yamur, or Jamur, is located in the corridor. The lake is drained by the Omba River, which follows the corridor southwards to empty into the Arafura Sea southeast of Etna Bay. [2]
The isthmus is covered in lowland rain forest. There is montane rain forest in the Wandammen Mountains above 1000 meters elevation. [4]
The isthmus is a transition zone between some of New Guinea's main ecological regions. Ornithologists Jared Diamond, David Bishop, and Richard Sneider describe it as a 'double suture zone', where the avifaunas of New Guinea's northern lowlands and southern lowlands, which are otherwise separated by the Central Highlands, can mingle, as can the avifaunas of the western peninsulas and New Guinea's main mass. [2]
Lake Yamur is home to wetland birds and waterfowl, [2] , as well as an endemic species of fish, the Yamur Lake grunter (Variichthys jamoerensis), and a population of bull shark (Carcharhinus leucas). [5]
Western New Guinea, also known as Papua, Indonesian New Guinea, and Indonesian Papua, is the western, Indonesian half of the island of New Guinea. Since the island is alternatively named Papua, the region is also called West Papua.
The South Halmahera–West New Guinea (SHWNG) languages are a branch of the Malayo-Polynesian languages, found in the islands and along the shores of the Halmahera Sea in the Indonesian province of North Maluku and of Cenderawasih Bay in the provinces of Papua and West Papua. There are 38 languages.
The Bird's Head Peninsula or Doberai Peninsula, is a large peninsula that makes up the northwest portion of the island of New Guinea, comprising the Indonesian provinces of Southwest Papua and West Papua. It is often referred to as The Vogelkop, and is so named because its shape looks like a bird's head on the island of New Guinea. The peninsula at the opposite end of the island is called the Bird's Tail Peninsula. The peninsula just to the south is called the Bomberai Peninsula.
The northern variable pitohui is a species of pitohui in the family Oriolidae. It is found on New Guinea and a number of neighbouring islands. Its natural habitat is subtropical or tropical moist lowland forests. It is also one of the few known poisonous birds.
The Northern New Guinea lowland rain and freshwater swamp forests is a tropical moist broadleaf forest ecoregion of northern New Guinea.
Bomberai Peninsula is located in the Western New Guinea region. It is south of the Bird's Head Peninsula, and Bintuni Bay separates the two peninsulas. To the west lies the Sebakor Bay and to the south Kamrau Bay. On the southeast Arguni Bay lies between the peninsula and the Bird's Neck Isthmus.
New Guinea is the world's second-largest island, with an area of 785,753 km2 (303,381 sq mi). Located in Melanesia in the southwestern Pacific Ocean, the island is separated from Australia by the 150-kilometre wide Torres Strait, though both landmasses lie on the same continental shelf, and were united during episodes of low sea level in the Pleistocene glaciations as the combined landmass of Sahul. Numerous smaller islands are located to the west and east. The island's name was given by Spanish explorer Yñigo Ortiz de Retez during his maritime expedition of 1545 due to the resemblance of the indigenous peoples of the island to those in the African region of Guinea.
The Central Range montane rain forests is a tropical moist forest ecoregion on the island of New Guinea. The ecoregion covers the Central Range of the New Guinea Highlands, which extends along the spine of the island. The montane rain forests of the ecoregion are distinct from the surrounding lowland forests, and are home to many endemic plants and animals.
New Guinea, lying within the tropics and with extensive mountain areas, comprises a wide range of ecoregions. These include rainforests, grasslands and mangrove.
Sausapor is a small town and District in the Tambrauw Regency of Southwest Papua, Indonesia. The town is located on the northern coast of the Bird's Head Peninsula, also known as the Vogelkop Peninsula. According to the 2010 census, the kecamatan has a population of 2,633, and more recent figures reveal around 1000 people living in the main town of Sausapor. Sausapor is a major breeding ground for sea turtles and bird habitat.
Kaimana Regency is a regency in the south of West Papua province of Indonesia. It covers an area of 18,500 sq. km, and had a population of 46,249 at the 2010 Census and 62,256 at the 2020 Census; the official estimate as at mid 2022 was 63,633. The administrative centre is the town of Kaimana. The Mairasi languages are spoken in the regency, among other languages.
The Ayamaru Lakes are a group of lakes found in the west-central part of the Bird's Head Peninsula in Southwest Papua, Indonesia. The nearest village to the group is Greemakolo. The many villages around the Ayamaru Lakes speak Ayamaru language, a dialect of the Maybrat language.
The Vogelkop–Aru lowland rain forests is a tropical moist forest ecoregion in Indonesia. The ecoregion covers the peninsular lowlands of western New Guinea, along with the Aru Islands and other nearby islands.
The Vogelkop montane rain forests is a tropical moist forest ecoregion in western New Guinea. The ecoregion covers the mountains of western New Guinea's Bird's Head and Bomberai peninsulas.
The Southern New Guinea freshwater swamp forests is a tropical moist forest ecoregion in southern New Guinea. The ecoregion includes the extensive swamp forests of southern and western New Guinea.
The Yapen rain forests is a tropical moist forest ecoregion in Indonesia. The ecoregion covers the island of Yapen and smaller neighboring islands which lie north of New Guinea.
The Wandammen Peninsula, also known as the Wondiwoi or Wondiboy Peninsula, is a mountainous peninsula in western New Guinea. It extends northwards from the Bird's Neck Isthmus into Cenderawasih Bay. The Wandammen Mountains run north and south along the spine of the peninsula, rising from the shore up to 2,250 metres elevation, and extending southwards into the Bird's Neck Isthmus. The eastern slope of the mountains is steeper than the western slope. Roon Island lies off the north end of the peninsula.
The Weyland Mountains, also known as the Kobowre Mountains, are a mountain range in Western New Guinea. The Weyland Mountains are the westernmost mountains in New Guinea's Central Range, which extends eastwards to the island's southeastern tip.