Black-vented Shearwater
Encyclopedia
The Black-vented Shearwater (Puffinus opisthomelas) is a species
of seabird
. The bird
is 30–38 cm in size, with a 76–89 cm wingspan. Formerly considered a subspecies
of the Manx Shearwater
, its actual relationships are unresolved.
This species is pelagic, occurring in the Pacific Ocean
and the Gulf of California
. It comes closer to land than most other shearwater
s, so it sometimes can be seen from shore. It predominantly nests on offshore islands off north and western Baja California
, namely Isla de Guadalupe, Islas San Benito
and Isla Natividad
. It is fairly common off the United States
coast
of central and southern California
during the country's colder months.
Black-vented Shearwater is thought to feed on mainly small fish
. This bird nests in burrows
and caves; it is a colonial nester.
In the past, this bird had been threatened by feral
cats and other predators on its breeding islands, but the problem seems to have been largely eliminated. There is some loss of birds from commercial gill netting, and the species is classified as Near Threatened by the IUCN mainly due to the uncertain impact on it by the expanding fishing industry.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
. The bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
is 30–38 cm in size, with a 76–89 cm wingspan. Formerly considered 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 Manx Shearwater
Manx Shearwater
The Manx Shearwater is a medium-sized shearwater in the seabird family Procellariidae. The scientific name of this species records a name shift: Manx Shearwaters were called Manks Puffins in the 17th century. Puffin is an Anglo-Norman word for the cured carcasses of nestling shearwaters...
, its actual relationships are unresolved.
This species is pelagic, occurring in the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
and the Gulf of California
Gulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...
. It comes closer to land than most other shearwater
Shearwater
Shearwaters are medium-sized long-winged seabirds. There are more than 30 species of shearwaters, a few larger ones in the genus Calonectris and many smaller species in the genus Puffinus...
s, so it sometimes can be seen from shore. It predominantly nests on offshore islands off north and western Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
, namely Isla de Guadalupe, Islas San Benito
Islas San Benito
The Islas San Benito lie in the Pacific Ocean off the west coast of the Mexican state of Baja California, 25 km west of Cedros Island. They are part of the Cedros Island delegación, a subdivision of Ensenada , Baja California....
and Isla Natividad
Isla Natividad
Isla Natividad is an island in the Pacific Ocean 6 km west off Punta Eugenia, the northwestern headland of the Mexican state of Baja California Sur. 200 meters off its northwestern end lies Roca María at , with an area of 0.074 km²...
. It is fairly common off the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
of central and southern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
during the country's colder months.
Black-vented Shearwater is thought to feed on mainly small fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
. This bird nests in burrows
Burrows
Burrows is a provincial electoral division in the Canadian province of Manitoba. It was created by redistribution in 1957, and formally came into existence in the provincial election of 1958. The riding is located in the northern part of Winnipeg....
and caves; it is a colonial nester.
In the past, this bird had been threatened 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...
cats and other predators on its breeding islands, but the problem seems to have been largely eliminated. There is some loss of birds from commercial gill netting, and the species is classified as Near Threatened by the IUCN mainly due to the uncertain impact on it by the expanding fishing industry.
External links
- Black-vented Shearwater Photos
- Black-vented Shearwater photo gallery – VIREO
- Photo-High Res – southwestbirders
- Photo-High Res; Article – "Santa Barbara County"–Photo Gallery-(2004)
