Ruff

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Ruff
Ruff (Calidris pugnax), splendid plumage

Ruff ( Calidris pugnax ), splendid plumage

Systematics
Class : Birds (aves)
Order : Plover-like (Charadriiformes)
Family : Snipe birds (Scolopacidae)
Genre : Sandpiper ( Calidris )
Type : Ruff
Scientific name
Calidris pugnax
( Linnaeus , 1758)

The ruff ( Calidris pugnax , Syn . : Philomachus pugnax ) is a strictly protected, almost 30 cm large snipe bird of the Palearctic , which breeds in the northern tundra but also in humid low meadows and moors all over Eurasia . Ruffs are migratory birds . Breeding birds from northwestern Europe mostly overwinter in inland areas of West Africa, e.g. B. in the inner Niger Delta in Mali . On the migration into the breeding areas, ruff can be seen on moist lowlands or on muddy surfaces.

The 2015 Red List of Breeding Birds in Germany lists the species in Category 1 as threatened with extinction in Germany, whereby it should be noted that Germany is on the edge of the range of the species. Worldwide, the species is in no way endangered and is therefore listed in the international Red List in the level of least endangerment, namely “not endangered” ( least concern ).

Appearance

The ruff males reach a height of 26 to 32 centimeters and weigh between 130 and 230 grams. The wingspan is 55 to 60 centimeters. In the breeding dress, most of the males have a black, orange, maroon or white collar, which has given them the English name ruff (collar).

Females are noticeably smaller than most males. They reach a height of 20 to 25 centimeters and weigh between 70 and 150 grams. Their wingspan is 47 to 52 centimeters. They can therefore be distinguished from the males by their size even in the plain dress.

distribution

The breeding area of ​​the ruff extends from northwestern Europe over the coastal lowlands of northern central Europe and the humid taiga of eastern Europe to the tundras of eastern Siberia, where they occur as far as the Chukchi peninsula . Main areas of distribution are Russia and Fennoscandinavia. They are absent on Iceland and all arctic islands of Russia. In the Netherlands, Germany and Poland only remnants are found, in Hungary the ruff is only an irregular breeding bird.

Ruffs are long-distance migrants. Their main winter quarters are found in Africa south of the Sahara and in southern Asia. In small numbers they also overwinter in the Middle East and the Mediterranean region and rarely in the Atlantic Western Europe. Winter populations in Africa can be very large. In February 1972 more than a million ruff were observed in Senegal and in the Lake Chad area in March 1957 more than 500,000 individuals.

habitat

Ruff in Mecklenburg

The ruff is a breeding bird of wet lowland meadows, bogs, sedge meadows and moist tundra. In Central Europe, it is mainly found near the coast and occurs there in meadows interspersed with pools and ditches that are used extensively. The nest locations are relatively dry. The feeding places are either by the water or on a damp surface. Very short vegetation is generally necessary for the chicks to move.

During the passage, they stay on muddy surfaces, damp meadows and fields. In their winter quarters they use fresh and brackish water as well as rice fields.

Reproduction

Gelege, Museum Wiesbaden collection

In the ruff, the females reach sexual maturity in the first year of life, but they usually breed for the first time in the second year of life. Annual birds have very little chance of copulation with the males, as the decorative feathers develop relatively late.

Courtship and mating strategy

Two males in splendid dress
Adult female

Ruffs have a very complicated pairing system, the English term is lekking behavior , which can be translated as arena courtship behavior. Ruff courtship arenas are usually small, 1 × 1 m areas of mud near small bodies of water near the breeding area. However, there are also arenas in the train area. The same courtship arenas are traditionally used every year. Males present themselves to the females in their courtship arenas, who then choose the male with whom they want to mate.

There are three types of male mating strategies, at least two of which are determined by genetic polymorphism. The males who pursue the various strategies can be distinguished from one another by characteristics of the plumage, size and behavior. The most common strategy of the "resident male" (84%) has a deep black or maroon to orange-red collar in the breeding plumage. These males defend small arenas about 1 × 1 m in size, showing an aggressive behavior especially towards the males who wear a dark collar. Here they actively court for females who come to these arenas during the mating season to select males.

Satellite males are less common (16%). They are marginally smaller than resident males and have a white or at least very light collar. They do not defend their own arenas, instead they stay close to resident males on the edge of their arenas. That way they can get hold of pairings every now and then. The satellites are tolerated by the residents because if a satellite is present, the females mate with residents more often. A specific recruitment behavior of the males with dark collars was even observed. If a dark-rimmed bird defends its arena alone and a light-rimmed male appears at the edge of the arena, then the dark-rimmed bird bends its legs in the heel joints and points its beak perpendicular to the ground. This is understood as an invitation to join the dark-rimmed bird in the arena. The reason why females find arenas occupied by two such males more attractive has not yet been clarified. Both of these reproductive strategies are inherited as an autosomal trait.

A third strategy was discovered by an attentive Frisian bird ringer : He noticed that the wing lengths had a three-peaked distribution and not a two- peaked distribution , as is the case with sexual size dimorphism . The middle class birds, which were very rare (<1%), looked like females. Both sections of dead animals and DNA tests revealed that these birds were also males. These males, called feathers, do not molt into the breeding plumage, but keep their simple plumage even during the mating season. It is believed that feathers sneak matings by pretending to be female and thus avoid the aggression of the residents. It is not known whether this strategy is hereditary, but it is clear that such birds will remain a feather for a lifetime. The name Faeder comes from Frisian and means “ ancestor ”.

The mating behavior of ruffs is not limited to arenas. Males also advertise outside of the arenas for females, who are then mostly occupied with feeding. As a result, males mate around six times as often inside an arena as outside of arenas.

Evolution of mating strategies

Ruff in youth dress

Two new studies have shown that the genetic polymorphism that determines the mating behavior of the ruff is due to a major restructuring on chromosome 11 of the animals. The first genetic change occurred around 3.8 million years ago when part of the resident chromosome 11 detached and was re-installed in the wrong orientation. This process, called inversion , gave rise to the so-called feather allele . About 500,000 years ago, there were again rare recombination events between the feather and resident alleles. The result was a satellite allele. The feather is therefore not, as its name suggests, the " clock cock " of all three male forms, but arose from the resident and therefore only evolutionarily older than the satellite males . The 4.5 megabases (MB) inversion affects around 90 genes , one of which is the CENPN gene, which is located precisely at the breakpoints of the two chromosome pieces. The inactivation of the gene has serious consequences for the organism and the family tree analyzes of a ruff colony that had been held captive for 30 years showed that there was never an individual there who carried the inversion in a homozygous form. The scientists therefore assume that two defective copies of this gene - and thus the inversion - are fatal. Over the past 3.8 million years, mutations have continued to accumulate in the inversion. These include three deletions , i.e. sections of DNA that are no longer present. Two of these deletions concern evolutionarily highly conserved areas near the two genes HSD17B2 and SDR42E1, both of which are necessary for the production of steroid hormones . Hormone measurements from courting ruff have shown that resident males have high levels of testosterone in their bodies during mating season , with both satellite and feather males only showing an increase in androstenedione , an intermediate product in testosterone synthesis . The authors conclude that the removal of the evolutionarily conserved element changes the expression of HSD17B2 and SDR42E1 and thus led to different behavior and appearance of the male ruff.

Rearing the young birds

From the choice of the nest location to the fledgling of the young birds, brood care is exclusively a matter for the females. The nest is usually well hidden in the vegetation, and the vegetation can be drawn together like a hood over the nest. It is mostly found in meadows on the edge of flood zones or wet places. Laying begins from May to the beginning of June, in Fennoscandinavia ruffs do not lay their eggs until the end of May. The clutch usually comprises four eggs. These are top-shaped and have a gray to olive green base color. They are mottled ash gray and dark brown, the mottling being particularly dense at the obtuse pole. The laying interval is 24 to 36 hours, the females only begin to breed after the last egg has been laid. The incubation period is 20 to 23 days. During the first seven to twelve days of life hudert the female boys. They are fed only a short time after hatching. The young birds peck for food independently after just a few days. They fledge between 25 and 28 days.

Duration

Ruff with white collar

Inventory development and inventory

The ruff was widespread in Central Europe until the 19th century. Drainage measures and changes in agriculture led to habitat losses, with the result that for 150 years there has been a sustained and dramatic loss of stocks and the abandonment of breeding areas both in Central Europe and in other regions of Europe. The abandonment of breeding areas began in the peripheral breeding areas near the low mountain ranges. In Baden-Wuerttemberg, Hesse and Saxony-Anhalt there were already no breeding stocks left at the beginning of the 20th century. In Bavaria, Hungary and Austria, the populations became extinct between the 1930s and 1950s. In the north of Central Europe, small inland deposits persisted until the 1940s and 1950s, at the beginning of the 21st century there are only larger inland deposits in the Netherlands and Poland. The population in Belgium expired in 1977, in the German Elbe lowlands in 1988. Since 1999 there have also been no evidence of breeding for the Elbe marshes. There were also dramatic declines on the North Sea coast. At the beginning of the 20th century there were around 10,000 ruff females in the Netherlands, 6,000 in the 1950s and only 100 to 140 by the end of the 20th century. Today ruffs are completely restricted to protected areas. The main cause of the dramatic decline in population is habitat destruction through melioration , plowing of grassland, embankment, drainage and lowering of the groundwater level, as well as afforestation of moors, peat removal and the abandonment of grazing. Numerous clutches and young birds are lost due to early mowing.

Isolated broods still occur in Germany (2005: 20–40 breeding pairs) and the Netherlands, but the original breeding population in this area is considered to be extinct. The protective measures included intensive protection or the creation of new, extensively used wet grassland, river plains and wet bog meadows as well as the protection and maintenance of salt grassland and salt pastures.

Inventory forecasts

The ruff is considered to be one of the species on which global warming will have a particularly significant impact. A research group that, on behalf of the British environmental authority and the RSPB, examined the future distribution of European breeding birds on the basis of climate models, assumes that 58 percent of the current range of this species will no longer offer a suitable habitat by the end of the 21st century. As a result of global warming, the ruff may be able to colonize Novaya Zemlya and parts of Svalbard . The area gains cannot compensate for the area losses further south and west. According to these forecasts, the potential future distribution area will only correspond to 48 percent of the size of today's distribution area.

Protection status

Ruff in Nederlandsche Vogelen , Part 1 (1770)

The ruff is listed in Germany in Appendix 1 to the Federal Species Protection Ordinance. It is a species in Appendix I of the EU Birds Directive (RL 2009/147 / EC).

literature

  • Hans-Günther Bauer, Einhard Bezzel and Wolfgang Fiedler (eds.): The compendium of birds in Central Europe: Everything about biology, endangerment and protection. Volume 1: Nonpasseriformes - non-sparrow birds. Aula-Verlag Wiebelsheim, Wiesbaden 2005, ISBN 3-89104-647-2 .
  • AJ Beintema, O. Moedt and D. Ellinger: Ecological Atlas van de Nederlandse weidevogels . Schuyt & Co, Haarlem 1995, ISBN 90-6097-391-7 .
  • Richard Sale: A Complete Guide to Arctic Wildlife , published by Christopher Helm, London 2006, ISBN 0-7136-7039-8 .

Web links

Commons : Ruff ( Calidris pugnax )  - Album with pictures, videos and audio files
Wiktionary: ruff  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Ruff ( Calidris pugnax ) at HBW Alive
  2. ↑ Christoph Grüneberg, Hans-Günther Bauer, Heiko Haupt, Ommo Hüppop, Torsten Ryslavy, Peter Südbeck: Red List of Germany's Breeding Birds , 5 version . In: German Council for Bird Protection (Hrsg.): Reports on bird protection . tape 52 , November 30, 2015.
  3. ↑ BirdLife International 2016: Calidris pugnax , The IUCN Red List of Threatened Species.
  4. ↑ a b c Sale, p. 200
  5. ↑ a b c Bauer et al., P. 515
  6. ^ Joan Roughgarden : Evolution's Rainbow: Diversity, Gender, and Sexuality in Nature and People. University of California Press, Berkeley 2004, ISBN 0-520-24073-1 , p. 117 and p. 118
  7. ^ DB Lank, CM Smith, O. Hanotte, T. Burke & F. Cooke (1995): Genetic polymorphism for alternative mating behavior in lekking male ruff Philomachus pugnax. Nature 378, pp. 59-62, doi : 10.1038 / 378059a0 .
  8. ↑ J. Jukema & T. Piersma (2006): Permanent female mimics in a lekking shorebird. Biology Letters 2, pp. 161-164, doi : 10.1098 / rsbl.2005.0416 .
  9. ^ Joan Roughgarden : Evolution's Rainbow: Diversity, Gender, and Sexuality in Nature and People. University of California Press, Berkeley 2004, ISBN 0-520-24073-1 , p. 117
  10. ↑ Sangeet Lamichhaney, Guangyi Fan, Fredrik Widemo, Ulrika Gunnarsson, Doreen Schwochow Thalmann: Structural genomic changes underlie alternative reproductive strategies in the ruff (Philomachus pugnax) . In: Nature Genetics . tape 48 , no. 1 , January 1, 2016, ISSN  1061-4036 , p. 84-88 , doi : 10.1038 / ng.3430 ( nature.com [accessed May 12, 2016]).
  11. ↑ Clemens Küpper, Michael Stocks, Judith E. Risse, Natalie dos Remedios, Lindsay L. Farrell: A supergene determines highly divergent male reproductive morphs in the ruff . In: Nature Genetics . tape 48 , no. 1 , January 1, 2016, ISSN  1061-4036 , p. 79–83 , doi : 10.1038 / ng.3443 ( nature.com [accessed May 12, 2016]).
  12. ↑ Clemens Küpper, Michael Stocks, Judith E. Risse, Natalie dos Remedios, Lindsay L. Farrell: A supergene determines highly divergent male reproductive morphs in the ruff . In: Nature Genetics . tape 48 , no. 1 , January 1, 2016, ISSN  1061-4036 , p. 79–83 , doi : 10.1038 / ng.3443 ( nature.com [accessed May 12, 2016]).
  13. ↑ Sangeet Lamichhaney, Guangyi Fan, Fredrik Widemo, Ulrika Gunnarsson, Doreen Schwochow Thalmann: Structural genomic changes underlie alternative reproductive strategies in the ruff (Philomachus pugnax) . In: Nature Genetics . tape 48 , no. 1 , January 1, 2016, ISSN  1061-4036 , p. 84-88 , doi : 10.1038 / ng.3430 ( nature.com [accessed May 12, 2016]).
  14. ↑ Bauer et al., P. 517
  15. ↑ Bauer et al., P. 516
  16. ^ Brian Huntley, Rhys E. Green, Yvonne C. Collingham, Stephen G. Willis: A Climatic Atlas of European Breeding Birds , Durham University, The RSPB and Lynx Editions, Barcelona 2007, ISBN 978-84-96553-14-9 , P. 185