Sea geese

Sea geese
Brent Goose ( Branta bernicla )
Systematics
Order : Goose birds (Anseriformes) Family : Duck birds (Anatidae) Subfamily : Geese (anserinae) Tribe : Real geese (Anserini) Genre : Sea geese
Scientific name
Branta
Scopoli , 1769

The sea geese ( Branta ) are a genus of real geese (Anserini) belonging to the family of duck birds (Anatidae) within the order of the geese birds (Anseriformes). They have a much darker plumage than the field geese , a black beak and black feet. The scientific generic name Branta comes from the English Brent goose (= black goose ), which there only refers to the brent goose .

features

Sea geese vary greatly in size and weight from species to species - and even within them. The different subspecies of the Canada goose get smaller from south to north. The smallest species of the genus is the pygmy Canada goose, 55 centimeters long and 1.5 kilograms . At 109 centimeters and up to 8 kilograms, Branta canadensis maxima , a subspecies of the Canada goose , is the largest. They differ from the closely related field geese in their fine, black beak, on the upper half of which no horn lamellae can be seen, the dark gray to black legs and the distinct two-tone color: while the neck, head and, in some species, the breast are black the fuselage with the wings lighter grayish or brownish. There is always a special head and / or neck markings, either in the form of cheek patches, hoods, neck rings or patches and stripes. As with all real geese, there is no visible sex dimorphism .

The Hawaiigans differs significantly from the other species. Selection pressure from an unsuitable habitat (lava fields, shrubbery) caused the development to become a species that lives almost exclusively on land with long legs, robust toes and receding webs.

Way of life and train

Sea geese lay 3 to 6 white to creamy yellow, at most slightly shiny and finely grained eggs in a hollow in the bottom that can be lined with nesting material. The nesting area is always padded with down feathers .

Except for the Hawaiians, the sea geese are more or less far-moving migratory birds. Mention should be made here of the migration performance of the dark-bellied brent goose . It moves from Siberia to the British and French coasts every year, in spring they gather in the Dutch Wadden Sea to move away. The entire world population of the red-necked goose visits the coasts of the Black Sea and Caspisees in the winter half-year .

Systematics

The sea geese genus includes the following six recent species :

German name	Scientific name	distribution	Hazard level Red List of IUCN	Remarks	image
Canada Goose	Branta canadensis ( Linnaeus , 1758)	It is originally from North America and North Asia. Introduced in Europe, it has established itself here as a breeding bird.	( Least Concern - not at risk)	7 subspecies 65 to 109 centimeters long. Gray-brown trunk, black neck and head with white or yellowish-white patch on the cheek (or patch on the cheek and forehead).
Little Canada Goose	Branta hutchinsii ( Richardson , 1832)	North America, Greenland, Russia.	( Least Concern - not at risk)	6 subspecies 55 to 65 inches long. Like Canada Goose, gray-brown body, black neck, and cheek patches; but significantly smaller and with a shorter beak. Some subspecies have a white ring above the chest.
Brent Goose	Branta bernicla ( Linnaeus , 1758)	Tundras of North America and North Asia, Greenland.	( Least Concern - not at risk)	3 subspecies 61 inches long. Dark goose with a ring on the black neck, the upper side also darker. Light flanks and, depending on the subspecies, light or dark belly.
Barnacle goose or barnacle goose	Branta leucopsis ( Bechstein , 1803)	Rock ranges and tundras of Greenland and North Asia.	( Least Concern - not at risk)	monotypically gray-white-black-banded coat and wings, white belly. The chest, neck and head are black, the face is white.
Red-necked goose	Branta ruficollis ( Pallas , 1769)	Endemic to Northern Siberia, breeds in open tundra.	( Vulnerable - endangered)	monotypically quite dark: black neck, back and wings, black belly with white flanks. The neck is patterned reddish and white, the red predominates.
Hawaiigans	Branta sandvicensis ( Vigors , 1833), Syn . : Nesochen sandvicensis	Endemic to Hawaii , more precisely to the islands of Hawaiʻi , Kauaʻi , Maui and Molokaʻi .	( Vulnerable - endangered)	monotypically 64 centimeters long. Gray-brown body like the Canada goose, black head and neck. From the cheeks down to the chest, the front neck is yellowish with black lines. Long legs with receding webbed feet as a result of adaptation to the habitat.

The Little Canada Goose has only been recognized as an independent species since 2004. Until then it was listed as one of the numerous subspecies of the Canada goose.

Occasionally the three subspecies of the Brent Goose, Br. B. bernicla , Br. b. hrota and Br. b. nigricans treated as species.

Sea geese in Hawaii

On the Hawaiian Islands, radiation of the Canada goose resulted in three species: the recent Hawaiian goose or Nene ( Branta sandvicensis ) as well as the extinct giant Hawaiian goose ( Geochen rhuax ) and the Nene-Nui ( Branta hylobadistes ). The latter two have already been exterminated by the Polynesian population. From a genetic point of view, all three species lie within the intraspecific variability of the Canada goose ( Branta canadensis ), which still appears occasionally in Hawaii today. The scientific name of the giant Hawaiigans is probably invalid ( nomen nudum ), according to the DNA analyzes it also belongs to the genus Branta .

All three types are either bad flyers or flightless. Even the airborne Hawaiian goose that is still alive today differs so much from the Canada goose that some researchers have granted it its own genus ( Nesochen ). Since it lives purely in the country, it has no webbed feet. The flightless species, which are closely related to it, have continued this development and are even more heavily built with smaller wings and a smaller sternum as a starting point for the flight muscles. You are therefore unable to fly. With these characteristics, all three species are more adapted to life on the ground. Unlike their ancestors, they do not live near water. They feed on grass, herbs, and leaves.

On the islands populated by sea geese and moa nalos , some plants of the genus Cyanea ( bluebell family ) have developed thorn-like structures and leaves in which the leaves of young plants differ from those of adults. Both were probably used for defense against sea geese and moa nalos. The differences in leaf shape make it harder for birds to recognize good-tasting plants by their appearance.

literature

• Limbrunner, Bezzel, Richarz, Singer: Encyclopedia of Breeding Birds in Europe. Franckh-Kosmos-Verlags GmbH & Co. KG, Stuttgart 2007, ISBN 978-3-440-11110-9 .
• Viktor Wember: The names of the birds of Europe. 2nd Edition. Aula Verlag GmbH, Wiebelsheim 2007, ISBN 3-89104-709-6 .
• Bernhard Grzimek: Grzimeks Tierleben - Volume 7 - Birds 1. Deutscher Taschenbuch Verlag GmbH & Co.KG, Munich 1968.
• Colin Harrison, Peter Castell: Fledglings, Eggs and Nests of Birds - Europe, North Africa and the Middle East. 2nd Edition. Aula Verlag GmbH, 2004.
• Ber van Perlo: Birds of New Zealand, Hawaii, Central and West Pacific. HarperCollins Publishers, 2011.
• National Geographic Society: National Geographic Field Guide to the Birds of North America. 2006, ISBN 0-7922-5314-0 .
• TJ Givinish, KJ Sytsma, JF Smith, WJ Hahn: Thorn-like prickles and heterophylly in Cyanea: Adaptations to extinct avian browsers on Hawaii? In: PNAS. Vol. 91, No. 7, Evolution, 1994, pp. 2810-2814.
• Helen F. James, Thomas W. Stafford, David W. Steadman, Storrs L. Olson, Paul S. Martin, AJT Jull, and Patrick C. McCoy: Radiocarbon Dates on Bones of Extinct Birds from Hawaii. In: PNAS. Vol. 84, No. 8, Evolution, 1987, DOI: 10.1073 / pnas.84.8.2350 , pp. 2350-2354.
• Storrs L. Olson, Helen F. James: Descriptions of thirty-two new species of birds from the Hawaiian Islands: Part I. Non-Passeriformes. In: Ornithological Monographs. No. 45, 1991, ( Online ; PDF; 5.0 MB).

Web links

Commons : Sea Geese ( Branta )  - Collection of images, videos and audio files

• Avibase

Individual evidence

1. ↑ Wember, p. 80.
2. ↑ Grzimek, p. 288
3. ^ Van Perlo, p. 90
4. ↑ Grzimek, pp. 287-288
5. ^ National Geographic Society, p. 24
6. ↑ Grzimek, pp. 287-288
7. ↑ Grzimek, p. 287
8. ↑ ^{a b} Grzimek, pp. 288-289.
9. ^ Harrison, Castell, p. 280.
10. ↑ Limbrunner, Bezzel, Richarz, Singer, p. 126.
11. ↑ Branta canadensis Avibase - the world bird database. Retrieved September 24, 2011.
12. ↑ ^{a b} Branta hutchinsii Avibase - the world bird database. Retrieved September 24, 2011.
13. ↑ ^{a b} Branta bernicla Avibase - the world bird database. Retrieved September 24, 2011
14. ↑ Branta leucopsis Avibase - the world bird database. Retrieved September 24, 2011.
15. ↑ Branta ruficollisi Avibase - the world bird database. Retrieved September 24, 2011.
16. ↑ Branta sandvicensis Avibase - the world bird database. Retrieved September 24, 2011.
17. ↑ Ellen E. Paxinos, Helen F. James, Storrs L. Olson , Michael D. Sorenson, Jennifer Jackson, Robert C. Fleischer: mtDNA from fossils reveals a radiation of Hawaiian geese recently derived from the Canada goose (Branta canadensis) . In: Proceedings of the National Academy of Sciences 2002, Vol. 99, No. 3, pp. 1399-1404.