Sea bird

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In the vicinity of a breeding colony, different species of seabirds ( shark , razorbill and guillemot ) rest on the rocky coast of Lofoten .
Rockhopper penguins ( Eudyptes chrysocome ) in the surf zone of New Island , one of the Falkland Islands .

As seabirds or marine birds are called birds that are bound with their way of life largely to the sea. A total of 275 different species have adapted to life at sea. Typical sea birds are, for example, tube noses , which also include the albatrosses , which are particularly adapted to constantly flying over the sea. They use the updrafts over the waves, which give them buoyancy over a longer period of time. Other examples of sea birds are penguins , alken birds such as puffins or guillemots , oystercatchers and avocets .

general characteristics

Although seabirds often show very large differences in their way of life, their behavior and their physiology , striking features of a convergent evolution can also be identified. The special conditions of their environment and the use of specific food niches have led to similar adaptations across all regimes and families . The velvet duck , for example, has large nostrils through which it excretes the salt from the seawater it has swallowed. This feature is not found very often within the duck birds , but is typical , for example, of tube noses . Marine birds usually do not have as colorful plumage as other bird species. Their plumage is often inconspicuous black, white or gray to brown.

Sea birds live longer, begin to reproduce at an older age, and have fewer offspring than other bird species . As a rule, however, they invest more time in their offspring than is usual with other birds. Most of the marine birds nest in colonies, with the number of breeding pairs varying from a few dozen to several million. Some species are known for their long annual migration , crossing the equator and sometimes circling the earth.

Customization types

Basically, sea birds can be divided into two types of adaptation:

  • Sea birds such as terns and petrels live in the air space above the sea. They are consistently excellent sailors whose anatomical features include long, pointed wings and narrow, delicate legs.
  • Sea birds such as alks and penguins are mainly sea birds that swim on the surface of the water. They move underwater with the help of their short and strong legs and wings. That is why they are also known as wing divers.

Threat and protection

Sea birds and humans have a long history in common, as humans used birds as prey, fishermen were aware of gathering schools of fish through them , and seafarers found their way back to land through them.

While some species of gulls benefit from industrial fisheries and their litter, the human impact on the seas through pollution and overfishing is threatening the stocks of most seabird species. It has been calculated that the discards from the Lower Saxony shrimp fishery in 1993 alone were enough to feed around 60,000 seabirds for a year. Some species, such as herring gulls and black-headed gulls, use discard particularly well. In this respect, the discard probably leads to an unnatural increase in the population size of some gull species in the Wadden Sea and thus also to a shift in the natural species composition of the breeding coastal birds.

Seabirds mistake the plastic waste in the oceans for food and eat it. You feel full but eventually starve to death with a garbage-filled stomach. About 1 million seabirds and 100,000 other marine life die this way every year .

According to a NABU report from 2020, more than 300,000 seabirds die each year worldwide from deep-sea fishing, and in particular from longlines .

Familys

Not all species of a family have to be seabirds (e.g. long-tailed ducks and eider ducks , but not mallards ). Even if there is no scientifically defined delimitation, birds of the following orders or families can be referred to as sea birds:

See also

Web links

Commons : Sea Bird  - Collection of images, videos and audio files
Wiktionary: Seevogel  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ a b c Renate Kostrzewa: Die Alken des Nordatlantiks - Comparative breeding ecology of a group of sea birds , Aula-Verlag, Wiesbaden 1998, ISBN 3-89104-619-7 , p. 10
  2. ↑ Renate Kostrzewa: Die Alken des Nordatlantiks - Comparative Breeding Ecology of a Sea Bird Group , Aula-Verlag, Wiesbaden 1998, ISBN 3-89104-619-7 , p. 11
  3. ↑ Walter, U. & Becker, PH (1997) Occurrence and consumption of seabirds scavenging on shrimp trawler discards in the Wadden Sea. ICES Journal of Marine Science 54, 684-694.
  4. ↑ http://www.wwf.de/fileadmin/fm-wwf/pdf_neu/WWF-Studie_Krabbenbeifang_090219_Internet.pdf
  5. ↑ Plastic waste in the sea - facts and figures. (PDF; 289 KB) In: Wissenschaftsjahr.de. Retrieved January 14, 2019 .
  6. ↑ Hazards to birds - fishing. Retrieved May 12, 2020 .