Silver petrel

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Silver petrel
Silver petrel (Fulmarus glacialoides)

Silver petrel ( Fulmarus glacialoides )

Systematics
Class : Birds (aves)
Order : Tubular noses
Family : Petrels (Procellariidae)
Genre : Fulmar ( Fulmarus )
Type : Silver petrel
Scientific name
Fulmarus glacialoides
( A. Smith , 1840)

The silver petrel ( Fulmarus glacialoides ) or Antarctic fulmar is a seabird that belongs to the petrel family. It colonizes the southern seas and spends most of its time over the open sea. To keep predators away from himself and his nest, he spits them with his stomach oil. For the coastal inhabitants and sea nomads on the western and southern coastal strip of Tierra del Fuego , this bird was an important source of food.

description

The silver petrel is 45 to 50 cm tall and weighs 700 to 1000 g. The wingspan is 115 to 120 cm. At the breeding colonies, the bird makes cackling, chuckling and nasal noises. On the high seas he is less cheerful.

In the adult silver petrel, the head, neck, underside and tail are white. The top is white, dominated by gray areas in the area of ​​the wings. The whitish gray wings are dark gray at the tips. The rump and tail are white, the latter is also rounded. The legs are short and yellowish green. The sexes are colored the same, males are usually slightly larger than females. There are no known morphs .

The silver petrel has dark eyes that are accentuated by a gray rein patch. The bill is longer than that of the fulmar and differently colored. The dominant color of the beak is a flesh-colored color that is created by the perfused tissue under the transparent horny substance . The tip of the beak is dark gray. As with all tubular noses , the nose, which is elongated like a tube, is characterized by a bluish-gray color.

The silver petrel can briefly dive up to three meters deep. After a short run he rises from the water.

flight

The silver petrel sails with rigidly spread wings and leans its body sometimes to one side and sometimes to the other. Most of the time it flies close to the water. It aligns its flight with the rising and falling of the waves. Its wingbeats are quick and short. In the vicinity of cliffs, the updrafts allow him to glide.

distribution and habitat

Distribution map of the silver petrel

The silver petrel has a large distribution area. The worldwide extent of the breeding area alone is estimated at 50,000 to 100,000 km². The southern fulmar is in the Southern Ocean and in the southern parts of the Atlantic , the Pacific and the Indiks home. In winter it flies long distances up to the equator . The breeding sites are not only on the Antarctic mainland, but also on all islands up to the northern limit of the Antarctic cold water and, in small numbers, on some temperate-cold islands further north.

Way of life

nutrition

The silver petrel feeds on krill , fish , crabs , snails , cephalopods , other molluscs and jellyfish . He also eats carrion and fish waste. The food is picked or submerged from the surface of the water.

behavior

The silver petrel is diurnal and strictly territorial during the breeding season. The dispute over food is resolved by loud cackling. In places with a lot of food it forms swarms. Sometimes several thousand birds gather to feed on the drifting carcass of a whale . The birds do not let themselves be disturbed when they are resting or when they are looking for food.

Adult silver petrels defend their territory against native and alien competitors. They seldom engage in dangerous fights against conspecifics. Most of the time, quarrels at the breeding site are fought out with aggressive threatening gestures, which end with the competitors snapping at the other's wings. If the loser does not withdraw, he will be spat on with stomach oil until he leaves.

The silver petrel defends its nest by making coughing noises, falling against the intruder, and poking volleys of yellow stomach oil from its beak. The silver petrel aims 50 to 100 cm, sometimes 200 cm. He can spit several times in a row, albeit in decreasing amounts. The oil has an unpleasantly sweet, fishy odor that has a repellent effect. The stomach oil is usually used very effectively as a defense against skuas and other sea birds. Due to sticky and damaged feathers, these birds often die. Even young birds can spew stomach oil against anyone who approaches them.

The silver petrel can become contaminated with its own stomach oil, but it can remove it by bathing and preening its plumage. Because other birds are unable to dispose of the oil in the same way, there must be a mechanism in place that gives fulmars "immunity" to the effects of the oil. Fisher also reports that silver petrels use small amounts of the stomach oil when brushing their plumage to apply it to their feathers. Silver petrels presumably have a special feather structure.

The stomach oil consists mainly of triglycerides and unsaturated fatty acids . The oil has a low viscosity with a specific gravity of 0.88. It condenses into a wax at cool temperatures. The color varies from colorless to deep reddish brown, but is often clear yellow.

Reproduction and development

The silver petrel begins its first brood between the ages of six and twelve. If the climatic conditions are not too adverse, it breeds from October to March in large colonies, which are usually on the Antarctic mainland and on the offshore islands. At the breeding site, silver petrels lie on their stomachs and slide under the edge of the rock in case of danger.

Courtship and mating

Fulmarus glacialoides

The silver petrels appear in front of the breeding rock in October, but do not go ashore at first. The males arrive first and courtship on the water, rhythmically lifting their bodies, flapping their wings and screaming. In the case of the populations in the Pacific , they also tear open the beak and show the partner the bright orange throat.

After successful courtship on the water, the male stays near the selected female. After a while, it cackles loudly at the female and gently nudges it several times with its beak. At regular intervals it brings him food to show that he can support a family. After a while, copulation occurs . The couples stay together for a lifetime.

Brood care

In the midst of snow and continuous ice, silver petrels usually build their nests on steep cliffs or in steep rock walls so that they can land well against the wind and simply jump into the depths to take off. The nest usually consists of a simple depression in the rock, which is sometimes laid out with stones. Between December and January, a single white egg is incubated by both parents for 48 to 57 days, which peel off every few days. To protect it from the cold underground, you always wear it on the back of your webbed feet. If the egg is stolen or broken, the female will not lay a new one.

The young bird hatches in mid-January, wearing a very thick down fur and weighing around 60 grams. The two adult birds alternate between hoofing it for around ten days and guarding it for another five days. In addition, it is fed an oily paste made from half-digested cephalopods , other mollusks and jellyfish , so that it becomes noticeably fat. After two weeks he is left alone all day and only fed once a day. If someone approaches the nest in the absence of their parents, he spits oil on them as a defense. At the age of three weeks he can distinguish his parents from intruders for the first time. The nestling period lasts 41 to 57 days. At the age of six to seven weeks the young bird is already able to fly. In March he leaves the nest in the absence of his parents and from that moment on takes care of himself.

Life expectancy is 20 years and more.

Systematics

The silver petrel belongs to the subfamily of the seagull petrels (Fulmarinae), which form a monophyletic group. They are grouped together based on typical features of their skull and particularly large nasal tubes. The closest relative within the genus is the fulmar ( F. glacialis ), which inhabits the northern oceans.

The silver petrel is a monotypical species, which means that no subspecies are known.

Inventory and inventory development

The global population of the silver petrel is estimated at 4,000,000 individuals (Fishpool and Evans 2001), the Antarctic population is small. Global trends have not been identified, but the populations appear to be stable (del Hoyo et al. 1992). It is therefore assumed that the species does not meet the criteria for inclusion in the IUCN Red List . For these reasons, the species is classified as not endangered (LC).

Silver petrel and human

Silver petrel ( Fulmarus glacialoides )

The bird that Salvin and Godman found in Mexico (Mazatlan) in 1904 formed the basis for describing the species and was mentioned in their 1908 monograph on petrels . Even so, they were unable to provide the research with any additional information about the species or its occurrence outside of its known range. Bourne noted in 1967 that this bird was listed on the British Museum's catalog (Natural History, 1888-5-18-94) with no data , but was unable to track it. He is identified as Fulmarus glacialoides (fide Alan Knox).

In the course of research, this species has had many names. The American Ornithologists' Union (AOU) had it on the first list of North American birds for a long time under the Latin name Priocella antarctica . John James Audubon named it Procellaria tenuirostris in 1839 . Later it was also carried to Procellaria glacialoides (Cassin 1858), Priocella tenuirostris (Nelson 1883) and Fulmarus glacialoides (Coues 1903).

The silver petrel was an important source of food as meat or egg for the coastal inhabitants and sea nomads of the Alakaluf and the Yámana (Yaghan), who settled on the western and southern coastal strip of Tierra del Fuego . It was also used as a food bird by the natives of Chiloé . Since the 19th century, the meat of the silver petrel has served the European inhabitants of the Falkland Islands as a food supply for the winter. For the seal and whalers of South Georgia it was both part of the diet on land and companion (whale waste) on the high seas.

credentials

Individual evidence

  1. ^ J. Fisher: The Fulmar. Collins, London, 1952
  2. ↑ Birdlife Factsheet: Southern Fulmar
  3. ^ J. Fisher: The Fulmar. Collins, London, 1952
  4. ↑ John P. Dumbacher, S. Pruett-Jones: Avian chemical defense . Chapter 4: Nolan VJr, Ketterson ED, editors. Current Ornithology. Volume 13. New York: Plenary Press. p 137-74, 1996
  5. ↑ J. Warham: The petrels: Their ecology and breeding systems . San Diego: Academic Press, 1990
  6. ↑ PJ Weldon, JH Rappole: A survey of birds odorous or unpalatable to humans: possible indications of chemical defense . Journal of Chemical Ecology 23 (11): 2609-33, 1997
  7. ↑ C. Swennen: Observations on the effect of ejection of stomach oil by the fulmar Fulmarus glacialis on other birds . Ardea 62: 111-7, 1974
  8. ^ J. Warham, R. Watts, RJ Dainty: The composition, energy content and function of the stomach oils of petrels (Order Procellariiformes) . Journal of Experimental Marine Biology and Ecology 23: 1-13, 1976
  9. ↑ C. Swennen: Observations on the effect of ejection of stomach oil by the fulmar Fulmarus glacialis on other birds . Ardea 62: 111-7, 1974
  10. ^ J. Jacob: Stomach oils . Chapter 5: Farner DS, King JR, Parkes KC, editors. Avian Biology Volume VI. Volume VI. New York: Academic Press. p 325-40, 1982
  11. ^ J. Fisher: The Fulmar . London: Collins, 1952
  12. ^ J. Warham: The incidence, functions and ecological significance of petrel stomach oils . Proceedings of the New Zealand Ecological Society 24: 84-93, 1977
  13. ^ J. Warham: The incidence, functions and ecological significance of petrel stomach oils . Proceedings of the New Zealand Ecological Society 24: 84-93, 1977
  14. ↑ Kerri M. Skinner: Oil-spitting in fulmars: an example of chemical defense in birds? EN 570: Chemical Ecology, 1998, web link ( Memento of the original dated August 1, 2011 in the web archive archive.today ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.colostate.edu
  15. ^ ITIS Report: Fulmarus glacialoides (Smith, 1840) , web link
  16. ↑ Avibase Database: Silver Petrel (Fulmarus glacialoides) (Smith, A, 1840) , web link
  17. ↑ Birdlife Factsheet: Southern Fulmar
  18. ^ Richard C. Banks: Supposed Northern Records of the Southern Fulmar . National Ecology Research Center, US Fish and Wildlife Service; National Museum of Natural History, Washington, DC 20560, Weblink (PDF file; 65 kB)

literature

  • Michael Brooke: Albatrosses and Petrels across the World . Oxford University Press, 2004, ISBN 0-19-850125-0
  • J. Fisher: The Fulmar . Collins, London, 1952
  • FD Godman: A Monograph of the Petrels . Pt. 3. Witherby, London, 1908
  • KC Hamer, J. In Steele, S. Thorpe, K. Turekian: Birds: Procellariiformes. Encyclopedia of Ocean Sciences . Academic Press, London, 2001, ISBN 0-12-227430-X
  • J. Hector: Notes on the Antarctic petrel (Priocella antarctica) . Trans. NZ Inst. 9: 464, 1877
  • LM Loomis: A Review of the Albatrosses, Petrels and Diving Petrels . Proc. Calif. Acad. Sci., 4th ser., Vol. 2, pt. 2, no.12, 1918
  • RC Murphy: Oceanic Birds of South America . At the. Mus. Nat. Hist., New York, Vol. 1., 1936

Web links

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