Branta
Encyclopedia
The black geese of the genus
Branta are waterfowl
belonging to the true geese
and swan
s subfamily Anserinae
. They occur in the northern coastal regions of the Palearctic
and all over North America
, migrating
to more southernly coasts in winter, and as resident birds in the Hawaiian Islands
. Alone in the Southern Hemisphere
, a self-sustaining feral
population derived from introduced birds of one species
is also found in New Zealand
.
The black geese derive their vernacular name for the prominent areas of black coloration found in all species. They can be distinguished from all other true geese by their legs and feet, which are black or very dark grey. Furthermore, they have black bills and large areas of black on the head and neck, with white (ochre in one species) markings that can be used to tell apart most species.The Nēnē
, which is aberrant in many respects, has no white on the head or neck and fairly little black, being quite similar to the Swan Goose
in the color pattern of these areas. The latter species, a grey goose, also has a black bill, but its reddish-orange legs indicate its actual relationships. As with most geese, their undertail and uppertail coverts are white. They are also on average smaller than other geese, though some very large taxa
are known, which rival the Swan Goose
and the Black-necked Swan
in size.
The Eurasia
n species of black geese have a more coastal distribution compared to the grey geese which share the same general area of occurrence, not being found far inland even in winter (except for occasional stray birds or individuals escaped from captivity). This does not hold true for the American and Pacific species, in whose ranges grey geese are for the most part absent.
of black geese are known. In addition, one species has been described from subfossil
remains found in the Hawaiian Islands, where it became extinct in prehistoric times. Another undescribed prehistoric species from the Big Island
of Hawai‘i was extremely large and flightless; it is tentatively assigned to this genus due to being very peculiar. It is fairly certain that at least another species of this genus awaits discovery on the Big Island, judging from the facts that at least one species of Branta was found on every major Hawaiian island, and that remains of such birds have not been intentionally searched for on the Big Island (but see below).
The species and selected subspecies are:
Tentatively assigned to Branta:
The relationships of the enigmatic Geochen rhuax to this genus are unresolved. It was another prehistoric Big Island form and remains known only from some parts of a single bird's skeleton
, which were much damaged because the bird apparently died in a volcanic eruption
, with the bones being found in an ash-filled depression under a lava
flow. A presumed relation to the shelduck
s proposed by Lester Short in 1970 was generally considered highly unlikely due to that group's biogeography
, but more recently, bones of a shelduck-like bird have been found on Kaua‘i. Whether this latter anatid was indeed a shelduck is presently undetermined.
Similarly, two bones found on Oʻahu indicate the erstwhile present of a gigantic waterfowl on this island. Its relationships relative to this genus and the moa-nalo
s, enormous goose-like dabbling ducks, are completely undeterminable at present.
species of Branta have been described. Since the true geese are hardly distinguishable by anatomical
features, the allocation of these to this genus is somewhat uncertain. A number of supposed prehistoric grey geese have been described from North America
, partially from the same sites as species assigned to Branta. Whether these are correctly assigned – meaning that the genus Anser
was once much more widespread than today and that it coexisted with Branta in freshwater habitat which it today does only most rarely – is not clear. Especially in the case of B. dickeyi and B. howardae, doubts have been expressed about its correct generic assignment.
The former "Branta" minuscula is now placed with the prehistoric American shelducks, Anabernicula. On the other hand, a goose fossil from the Early-Middle Pleistocene of El Salvador
is highly similar to Anser and given its age and biogeography
it is likely to belong to that genus or Branta.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Branta are waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
belonging to the true geese
Goose
The word goose is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller....
and swan
Swan
Swans, genus Cygnus, are birds of the family Anatidae, which also includes geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometimes, they are considered a distinct subfamily, Cygninae...
s subfamily Anserinae
Anserinae
The Anserinae is a subfamily in the waterfowl family Anatidae. It includes the swans and true geese. Under alternative systematical concepts , it is split into two subfamilies, the Anserinae containing the geese , while the Cygninae contain the swans.A number of other waterbirds, mainly related to...
. They occur in the northern coastal regions of the Palearctic
Palearctic
The Palearctic or Palaearctic is one of the eight ecozones dividing the Earth's surface.Physically, the Palearctic is the largest ecozone...
and all over North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, migrating
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
to more southernly coasts in winter, and as resident birds in the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
. Alone in the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
, a self-sustaining 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...
population derived from introduced birds of one species
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...
is also found in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
.
The black geese derive their vernacular name for the prominent areas of black coloration found in all species. They can be distinguished from all other true geese by their legs and feet, which are black or very dark grey. Furthermore, they have black bills and large areas of black on the head and neck, with white (ochre in one species) markings that can be used to tell apart most species.The Nēnē
Nene
Nene may refer to:*River Nene, a river in England*Rolls-Royce Nene, a jet engine*Nene , also called Nēnē and Hawaiian Goose, Branta sandvicensis, a rare goose*Nene , a Seminole Indian word meaning "street"...
, which is aberrant in many respects, has no white on the head or neck and fairly little black, being quite similar to the Swan Goose
Swan Goose
The Swan Goose is a rare large goose with a natural breeding range in inland Mongolia, northernmost China, and southeastern Russia. It is migratory and winters mainly in central and eastern China...
in the color pattern of these areas. The latter species, a grey goose, also has a black bill, but its reddish-orange legs indicate its actual relationships. As with most geese, their undertail and uppertail coverts are white. They are also on average smaller than other geese, though some very large taxa
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
are known, which rival the Swan Goose
Swan Goose
The Swan Goose is a rare large goose with a natural breeding range in inland Mongolia, northernmost China, and southeastern Russia. It is migratory and winters mainly in central and eastern China...
and the Black-necked Swan
Black-necked Swan
The Black-necked Swan is the largest waterfowl native to South America. Males are and weigh 4.5-6.7 kg ; females are and weigh 3.5-4.4 kg . The wingspan ranges from . The body plumage is white with a black neck, head and greyish bill. It has a red knob near the base of the bill and...
in size.
The Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
n species of black geese have a more coastal distribution compared to the grey geese which share the same general area of occurrence, not being found far inland even in winter (except for occasional stray birds or individuals escaped from captivity). This does not hold true for the American and Pacific species, in whose ranges grey geese are for the most part absent.
Systematics
6–8 living speciesSpecies
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 black geese are known. In addition, one species has been described from subfossil
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
remains found in the Hawaiian Islands, where it became extinct in prehistoric times. Another undescribed prehistoric species from the Big Island
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
of Hawai‘i was extremely large and flightless; it is tentatively assigned to this genus due to being very peculiar. It is fairly certain that at least another species of this genus awaits discovery on the Big Island, judging from the facts that at least one species of Branta was found on every major Hawaiian island, and that remains of such birds have not been intentionally searched for on the Big Island (but see below).
The species and selected subspecies are:
- Brant Goose, Branta bernicla
- Pale-bellied Brant Goose, Branta (bernicla) hrota
- Black BrantBlack BrantThe Black Brant or Pacific Brent Goose, Branta bernicla nigricans, is a sub-species of the Brent Goose that breeds in Alaska and winters in Baja California. There are an estimated 115,000 black brant in the world and about 14,000 are taken each year by hunters. Fox predation of eggs is thought to...
, Branta (bernicla) nigricans
- Barnacle GooseBarnacle GooseThe Barnacle Goose belongs to the genus Branta of black geese, which contains species with largely black plumage, distinguishing them from the grey Anser species...
, Branta leucopsis - Canada GooseCanada GooseThe Canada Goose is a wild goose belonging to the genus Branta, which is native to arctic and temperate regions of North America, having a black head and neck, white patches on the face, and a brownish-gray body....
, Branta canadensis - Cackling GooseCackling GooseThe Cackling Goose is a North American bird of the genus Branta of black geese, which contains species with largely black plumage, distinguishing them from the grey Anser species....
, Branta hutchinsii – formerly included in B. canadensis- Bering Cackling Goose, Branta hutchinsii asiatica – a doubtfully distinct subspeciesSubspeciesSubspecies 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...
; extinct (c.1929)
- Bering Cackling Goose, Branta hutchinsii asiatica – a doubtfully distinct subspecies
- Red-breasted GooseRed-breasted GooseThe Red-breasted Goose is an endangered species of goose in the genus Branta. It is sometimes separated in Rufibrenta but appears close enough to the Brent Goose to make this unnecessary, despite its distinct appearance.- Description :All the species of the Branta genus are distinguished by their...
, Branta ruficollis - NeneNeneNene may refer to:*River Nene, a river in England*Rolls-Royce Nene, a jet engine*Nene , also called Nēnē and Hawaiian Goose, Branta sandvicensis, a rare goose*Nene , a Seminole Indian word meaning "street"...
, Nēnē, or Hawaiian Goose, Branta sandvicensis - Nēnē-nuiNene-nuiThe Nēnē-nui or Woodwalking Goose is an extinct species of goose that once inhabited Maui and possibly Kauai, Oahu and perhaps Molokai in the Hawaiian Islands...
or Woods-walking Goose, Branta hylobadistes (prehistoricLate Quaternary prehistoric birdsPrehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...
)
- Similar but hitherto undescribed remains are known from on Kauaʻi and Oʻahu.
Tentatively assigned to Branta:
- Giant Hawaii Goose, ?Branta sp. (prehistoricLate Quaternary prehistoric birdsPrehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...
)
The relationships of the enigmatic Geochen rhuax to this genus are unresolved. It was another prehistoric Big Island form and remains known only from some parts of a single bird's skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
, which were much damaged because the bird apparently died in a volcanic eruption
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
, with the bones being found in an ash-filled depression under a lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
flow. A presumed relation to the shelduck
Shelduck
The shelducks, genus Tadorna, are a group of large birds in the Tadorninae subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans....
s proposed by Lester Short in 1970 was generally considered highly unlikely due to that group's biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
, but more recently, bones of a shelduck-like bird have been found on Kaua‘i. Whether this latter anatid was indeed a shelduck is presently undetermined.
Similarly, two bones found on Oʻahu indicate the erstwhile present of a gigantic waterfowl on this island. Its relationships relative to this genus and the moa-nalo
Moa-nalo
The moa-nalo are a group of extinct aberrant, goose-like ducks that lived on the larger Hawaiian Islands, except Hawaii itself, in the Pacific...
s, enormous goose-like dabbling ducks, are completely undeterminable at present.
Early fossil record
Several fossilFossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
species of Branta have been described. Since the true geese are hardly distinguishable by anatomical
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
features, the allocation of these to this genus is somewhat uncertain. A number of supposed prehistoric grey geese have been described from North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, partially from the same sites as species assigned to Branta. Whether these are correctly assigned – meaning that the genus Anser
Anser (genus)
The waterfowl genus Anser includes all grey geese and sometimes the white geese. It belongs to the true geese and swan subfamily . The genus has a Holarctic distribution, with at least one species breeding in any open, wet habitats in the subarctic and cool temperate regions of the Northern...
was once much more widespread than today and that it coexisted with Branta in freshwater habitat which it today does only most rarely – is not clear. Especially in the case of B. dickeyi and B. howardae, doubts have been expressed about its correct generic assignment.
- Branta woolfendeni (Big Sandy Late Miocene of Wickieup, USA)
- Branta thessaliensisBranta thessaliensisBranta thessaliensis is a prehistoric species of black goose known from fossils found in Greece. It is among the earliest known members of its genus.Described in 2006, it was of similar size to the Canada Goose...
(Late Miocene of Perivolaki, Greece) - Branta dickeyi (Late Pliocene – Late Pleistocene of W USA)
- Branta esmeralda (Esmeralda Early Pliocene)
- Branta howardae (Ricardo Early Pliocene)
- Branta propinqua (Middle Pleistocene of Fossil Lake, USA)
- Branta hypsibata (Pleistocene of Fossil Lake, USA)
The former "Branta" minuscula is now placed with the prehistoric American shelducks, Anabernicula. On the other hand, a goose fossil from the Early-Middle Pleistocene of El Salvador
El Salvador
El Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...
is highly similar to Anser and given its age and biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
it is likely to belong to that genus or Branta.