Reunion consecration
| Reunion consecration | ||||||||||||
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Prepared Réunion consecration ( Circus maillardi ) ♂ in the Muséum d'histoire naturelle de la Réunion |
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| Scientific name | ||||||||||||
| Circus maillardi | ||||||||||||
| Verreaux , 1862 |
The Réunion Harrier ( Circus maillardi ) is a bird of prey from the kind of orders ( Circus ). The species endemic to the island of Réunion is one of the smallest harriers and lives in the wooded and bushy highlands of the island. It feeds mainly on small mammals and birds, which it prey on in dense vegetation. The breeding season is between January and April, the clutch consists of two to three eggs. The species was originally native to the neighboring main island of Mauritius , but died out there at an unknown time.
The Reunion consecration, known locally in Creole as Papangue, is one of the world's most endangered species of birds of prey. The population includes a maximum of 340 adult birds. In addition, there is the very small distribution area, which is limited to the less populated areas of Réunion. BirdLife International classifies the species as endangered for these reasons .
features
Physique and appearance
The Reunion consecration is a very small representative of its genus. Compared to other types of consecration, it has relatively short and rounded wings and short legs, but comparatively long third toes and claws. This body structure is an adaptation to the originally heavily forested mascarens and the mainly flying prey. There is a clear difference between the females and the males of the Reunion consecration both in terms of body size and plumage. Female individuals grow between 3 and 15% larger than males. Males of the Reunion harrier have a wing length of 340-360 mm and a tail length of 218-230 mm. Your barrel bone measures between 78 and 90 mm. Female birds reach a wing length of 370-390 mm and a tail length of 218-230 mm. The barrel bone of the female is also 78-90 mm long. The wingspan is about 2.4 times the body length in flight.
Male birds show a contrasting plumage color of black, gray and white tones. The face veil is uniformly black, it is framed by a black and white dashed collar that extends from the back of the head and neck over the throat to the chest. The back and upper wing-coverts are uniformly black, only the wing crease is colored white. The gray hand and arm wings of the male show a narrow, black subterminal band ; the outer six hand wings are completely black. The rump is white, the control feathers on the top uniformly gray with a black subterminal band. The belly and trousers are uniformly white and show at most a few black lines. The forearm covers and the underside of the wings are white, with the exception of the five outer, black hand wings, and a narrow, black subterminal band runs along the lower edge of the wing. The control springs are also gray on the underside and have a dark subterminal band.
The females have a radially brown and white dashed head starting from the beak. The dashed lines are darker and thicker on the face veil than on the rest of the head. The back and wings are uniformly dark brown, the only exception being the white bow of the wing. The rump is variably colored white, the tail feathers are brown on the upper side and show wide, dark banding. On the belly side there is a clear red-brown-yellowish dash on a white background from the chest to the trousers. The legs and wax skin are yellow in adult males and females, as is the iris .
Young birds in the first year are even darker brown than the females. On the top they are almost uniformly dark brown, only on the neck they have a light cream-colored spot. The rump is reddish-brown and is followed by dark-banded, brown control feathers. Young birds are dark brown on the chest and belly, the abdomen is reddish brown. Juvenile animals have maroon irises, yellow legs and yellow wax skin. The youthful plumage gradually changes into the adult plumage, whereby the males' belly first assumes a dashed pattern, later the undersides of the wings are lightened and finally the upper side of the plumage is also changed from brown to black and white.
Flight image
The Reunion consecration differs significantly in flight from the other species of the genus Circus . In terms of habit, it is more reminiscent of more compact hawks , especially in relation to the relatively short, rounded wings. The typical juggling flight at low altitude over spacious, open terrain is less common at the Reunion consecration. Instead, the Reunion consecration often flies in agile flight just above and between trees or along steep slopes. Sometimes it circles high above the vegetation. In addition, spectacular courtship flights with rapid maneuvers can be observed in the breeding season, especially in the male.
Vocalizations
Reunion consecrations have a repertoire of different calls, some of which are similar to those of other consecrations, and some are characteristic of the species. During the courtship flights, both sexes cry plaintively with kai pi-pi-pi-pi-pi or kai-ké-ké-ké . Compared to the rest of the genus, this is a rather complex call that is heard more often from the male. In addition, the male lets out a croaking chip during courtship . At the end of the courtship flight it utters a kie-kju shout. If the male brings food or chases away a rival, he calls out with a sharp pjiuu . Chicks and brooding females beg for food with a long pijou pijou . Young birds regularly give a similar call when they are in groups.
Spreading and migrations
The consecration of Reunion is endemic to the island of Reunion in the Indian Ocean . The distribution area used to include Mauritius , about 200 km away , but here the species died out at an unknown point in time. With 2507 km² the Reunion consecration has the smallest distribution area of all consecrations.
On Réunion, the higher parts of the island are mainly populated. Along the lower coastal areas there is no consecration of Reunion - with the exception of the northwest, the central northeast coast and the east - because human settlement there is particularly dense and the interference with the island's original vegetation is greatest. Inside the Cirque de Cilaos bird missing around Cilaos . The Plaine des Cafres in the south obviously does not offer a suitable breeding habitat, which is why there is also a gap here. The highest mountain regions around the Piton des Neiges are avoided by the Reunion consecration, as is the volcanic landscape of Grand Brûlé , which stretches from the Piton de la Fournaise to the east coast and is regularly shaken by eruptions.
Reunion consecrations are resident birds and do not undertake major migrations. Occasionally individuals appear in Mauritius as stray visitors. In late winter there are larger numbers over the sugar cane fields in the lowlands, which are otherwise avoided. The reason for this is the easier access to small animal prey in the then harvested fields, although this phenomenon was probably more pronounced in earlier centuries than in times of intensive agriculture that is predominant today.
habitat
The habitat of the Reunion consecration is rather untypical for consecrations. It consists primarily of mountain slopes, river valleys or basins that are not particularly extensive and overgrown with half-height shrubs and trees . The breeding habitats consist almost exclusively of dense undergrowth, savannah or forest clearings in higher elevations, only in some places they extend deeper into river valleys. Swampy and sparsely overgrown habitats are also used there.
In terms of hunting habitats, the consecration of Reunion is less demanding. Here she also uses agricultural areas, roadsides and golf courses or airfields. Most often, the Reunion consecration hunts over open and semi-open landscape along mountain slopes, heathland above the tree line and in forests in the lowlands. In addition, they are often hunted in sugar cane fields that are not used for breeding despite the dense vegetation. Dense primary forests, urban and suburban habitats and estuaries, however, are rarely used as hunting habitats.
The unusual use of the habitat results from changes in the island's vegetation since human settlement. While the marshland along the rivers and the coast were originally settled, agriculture and human settlement on the coast pushed the species further into the wooded highlands.
The breeding areas reach up to 1200 m, hunting is done at heights of up to 2600 m, with areas below 800 m being preferred for both breeding and hunting.
Way of life
Hunting and feeding
The Reunion consecration usually uses a surprise tactic when hunting. Prey animals are attacked from under cover of the undergrowth or branches or by swooping down a slope and startling prey. The hunting strategy known from other consecrations, in which prey is grabbed from the vegetation in low flight , is rarely pursued due to a lack of suitable areas and forms of vegetation. The Reunion consecration patrols along fixed routes, usually starting from the nesting site, or circling high up to spot prey. The birds are very active and spend a large part of the day in flight. You usually start hunting two hours after sunrise. When the young need to be fed, they start an hour earlier.
Around 50% of the food is mammals, and small birds, reptiles and amphibians are also preyed on. Basically, the Reunion consecration is opportunistic in terms of food intake and also eats carrion or bird eggs. The main diet is rats ( Rattus spp.) And great tenreks ( Tenrec ecaudatus ). The tenrek activity season between October and May coincides with the main breeding season for many species of birds on Réunion. In winter, these food sources are not available for the Reunion consecration, which is why it has to fall back on other prey. Among the birds, songbirds such as Réunion spectacle birds ( Zosterops olivaceus ) or feral domestic pigeons ( Columba livia ) are captured. The latter have apparently declined sharply outside of built-up areas due to the hunting by the Reunion consecration.
The high proportion of terrestrial mammals in today's diet is remarkable in that they were only introduced when they were colonized by Europeans in the 17th century. By then, the consecration of Reunion must have mainly fed on birds - now extinct pigeon and parrot species - and endemic bats . The Reunion consecration is the only remaining predator of the local fauna that can be found on the island all year round. As such, unlike many other bird species on the island, it was able to expand its ecological niche through the introduction of rats and other mammals.
Territorial behavior and settlement density
Reunion consecrations show hardly any territorial behavior. Hunting areas are often shared by neighboring breeding pairs. Aggressive behavior between the males only occurs during the mating season. The birds fly up and down around the nest with strong V-angles and drooping legs with loud calls.
The size of the hunting areas varies depending on the region and is between 3 and 6 km² per breeding pair. The highest settlement density was found in an 8 km long valley section of 16 km², which was settled by seven breeding pairs. In contrast, the settlement density within the large valley basins is rather low, with an average of two to three breeding pairs.
Courtship and brood
The mating season begins in October, with both sexes, but mainly the males, showing spectacular courtship flights. They ascend to great heights with plaintive cries and there begin to fly up and down in sinusoidal curves. The amplitude is 15-20 m. Shortly before the summit of each flight curve, they first flap their wings intensely, then perform a role and let the chip call be heard before they plunge down again. At the end of this sightseeing flight, they tumble down a tumble while shouting kie-kju , perform loops if they fall and finally land on the potential nesting site. This courtship ritual usually takes 10-15 minutes and is repeated several times a day. Sometimes it is done by several males at the same time, only rarely does the female take part.
The nest is built from October or November by both sexes directly on the ground or in low (1–3 m high) shrubs. It consists of twigs, measures 60–70 cm in diameter and has a depression in the middle of 20–25 cm deep. This hollow is lined with dry grass. The female lays 1–3 white eggs, 4.6–5.1 × 3.5–3.7 cm in size, on average 2.7. The eggs are laid between the beginning of January and the end of May, usually in February and March, and occurs after that of all other indigenous bird species. At this time, Réunion has warm and humid weather, while other species of harrier tend to breed in dry periods. The chicks hatch after 33–36 days and initially have a grayish-white downy plumage that turns yellow after 8–10 days. From this point on, the nestlings are actively moving around the nest. At the age of 45–50 days the young can fledge. During the next two months, they remain dependent on their parents, usually continue to move in the closer vicinity of the nest and are looked after by the father. They widen their radius of action step by step, but stay close to their parents all through the first year until December. With an average of 1.4 cubs flying out and 2.7 eggs per breeding pair and year, the reproductive rate for harriers is extremely low.
Systematics and research history
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Relationships of the Reunion consecration after Simmons 2000
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The first description was by Jules Verreaux and was published in Louis Maillard's Notes sur l'Île de la Réunion (Bourbon) in 1862 . The description included the plumage and body dimensions of adult, juvenile and sub-adult males; the female was evidently unknown to Verreaux. The species epithet devoted Verreaux Maillard, of several works on the ecology and natural history Réunions wrote. Verreaux justified this with the fact that Maillard was the first to differentiate the species from the Asiatic magpie harrier ( C. melanoleucos ). He also wanted to pay tribute to Maillard's efforts in researching the bird world by naming Réunion.
The Reunion consecration was regarded as a subspecies of the Western Palearctic Marsh Harrier ( C. aeruginosus ) according to the classical system of the genus Circus by Erwin Stresemann . In 1980 Dean Amadon and John Lewis Bull separated the much larger Madagascar harrier ( C. macrosceles ) and the Reunion harrier from the marsh harrier complex and, due to similarities in plumage and geographical proximity, placed them as subspecies in a common species C. maillardi . Based on ecological studies by Bretagnolle et al . and analyzes of the mitochondrial cytochrome b gene by Robert Simmons and Michael Wink in 2000, the consecration of the Reunion was finally granted species status.
In fact, the Reunion consecration is the sister taxon to the Madagascar consecration. Both species emerged from a common ancestor about 760,000 years ago. The sister taxon of the clade formed by both species is the Marsh Harrier. How the ancestor of the Reunion consecration reached the Mascarenes is unclear. Since the radiation within the narrow marsh harrier complex apparently originated in Australia, some authors assume that it immigrated in the Pleistocene from the Indian subcontinent via the archipelagos of the Maldives and Seychelles , which were then significantly higher than today.
A 1874 Mauritius discovered, first the genus Accipiter attributed subfossil was initially under the name Circus Alphonsi treated as a separate type of orders. However, doubts were expressed early on, and osteological comparisons finally confirmed that the consecration, which died out on Mauritius, belonged to the same species as the birds of Réunion. It is unclear when the consecration of the Reunion disappeared from there. In 1606 Cornelis Matelief de Jonge reported both falcons ( faucons ) - probably Mauritius falcons ( Falco punctatus ) - as well as " sparrows " ( éperviers ) on Mauritius. If the consecration of Réunion still existed on Mauritius when the first settlers arrived, it died out soon afterwards.
Existence and endangerment
The consecration of Reunion Island was described as frequent by the first settlers, but the species has traditionally been viewed as a pest and suspected of robbing chicken populations. Kills by humans were therefore common until the middle of the 20th century. Between 1706 and 1834 the species was not mentioned in any report from Réunion, which suggests that the consecration of Réunion was very rare at this time. Due to a sharp drop in the population between 1949 and 1967, the Reunion consecration was no longer officially classified as an agricultural pest in 1966, but it was not until 1974 that protective measures and a shooting ban were imposed. There was a significant recovery by the late 1970s, but it is unclear whether this was due to restricted hunting or the ban on the insecticide DDT .
With just a few hundred individuals, the Reunion consecration population is one of the smallest among all birds of prey. The exact estimates vary, so there is a choice of fewer than 100 breeding pairs up to 1740 breeding pairs. A number of 130 pairs would correspond to a total of 260 sexually mature individuals and around 500 birds in total. Although the population is currently stable, the maximum possible population has not necessarily been reached. BirdLife International has therefore listed the species as endangered since 2000 . The species is threatened above all by the decline in suitable breeding habitats as a result of the expansion of agricultural areas, the increase in tourism and road construction, as well as poaching and human shooting, which continue despite bans. Despite its growth since the 1960s, the small population remains endangered, especially since volcanic eruptions on Réunion regularly destroy large areas of vegetation and lead to a collapse of native birds. The same applies to cyclones : Cyclone Hyacinthe destroyed half of the bird population on Réunion in 1980 and destroyed almost all clutches. Both natural events thus represent a further factor of uncertainty for the population, which is still endangered by anthropogenic factors.
literature
- Armand Barau, Nicolas Barré, Christian Jouanin: Le Grand Livre des Oiseaux de la Réunion. Éditions Orphie, Paris 2005, ISBN 2-87763-263-6 .
- Vincent Bretagnolle, Thomas Ghestemme, Jean-Marc Thiollay, Carole Attié: Distribution, Population Size and Habitat Use of the Réunion Harrier, Circus m. maillardi . In: Journal of Raptor Research 34 (1), 2000. pp. 8-17. (Online as PDF )
- Vincent Bretagnolle, Jean-Marc Thiollay, Carole Attié: Status of Réunion Marsh Harrier Circus maillardi on Réunion island. In: RD Chancellor, B.-U. Meyburg (Ed.): Raptors at risk . World Working Group on Birds of Prey , Berlin & Hancock House, Blaine, WA 2000, ISBN 0-88839-478-0 , pp. 669-676.
- Michel Clouet: Le Busard de Maillard (Circus aeruginosus maillardi) de l'Île de la Réunion. In: L'Oiseau et la Revue Française de l'Ornithologie 48 (2), 1978. pp. 95-106.
- Anthony S. Cheke: An ecological history of the Mascarene Islands, with particular reference to extinctions and introductions of land vertebrates . In: AW Diamond (Ed.): Studies of Mascarene Island Birds . Cambridge University Press, Cambridge 1987, ISBN 0-521-25808-1 , pp. 5-89.
- Anthony S. Cheke: The ecology of the surviving native land-birds of Reunion . In: AW Diamond (Ed.): Studies of Mascarene Island Birds . Cambridge University Press, Cambridge 1987, ISBN 0-521-25808-1 , pp. 151-207.
- Anthony S. Cheke, Julian Hume: Lost Land of the Dodo. An Ecological History of Mauritius, Réunion & Rodrigues. T & AD Poyser, London 2008, ISBN 978-0-7136-6544-4 .
- James Ferguson-Lees , David A. Christie: Raptors of the World . Houghton Mifflin Harcourt, 2001, ISBN 0-618-12762-3 .
- Louis Maillard: Notes sur l'ile de la Réunion (Bourbon). Dentu, Paris 1862. ( Online )
- C. Mourer-Chauviré, R. Bour, S. Ribes: The taxonomic identity of Circus alphonsi (Newton & Gadow 1893) , the extinct harrier from Mauritius. In: Ibis 146, 2004. pp. 168-172.
- CG Jones: Aerial display of the Réunion Harrier. In: Gabar 4, 1989. pp. 22-23.
- Antoine Roussin (Ed.): Album de l'Île de la Réunion. New edition, Editions Orphie, Paris 2004, ISBN 2-87763-222-9 , pp. 293–295.
- Robert E. Simmons: Harriers of the World: Their Behavior and Ecology. Oxford University Press , 2000, ISBN 0-19-854964-4 .
Web links
- Circus maillardi on www.globalraptors.org
- Species factsheet: Circus maillardi . BirdLife International , 2011.
- Literature on the Reunion in the Global Raptor Information Network
- Circus maillardi inthe IUCN 2013 Red List of Endangered Species . Listed by: BirdLife International, 2012. Retrieved October 22, 2013.
Individual evidence
- ↑ a b c Maillard 1862 , p. 1961.
- ↑ a b Ferguson-Lees & Christie 2001 , p. 505.
- ↑ Ferguson-Lees & Christie 2001 , p. 507.
- ↑ a b c Ferguson-Lees & Christie 2001 , p. 506.
- ↑ Clouet 1978 , p. 96.
- ↑ a b c Clouet 1978 , pp. 97-98.
- ↑ Clouet 1978 , pp. 99-100.
- ↑ Simmons 2000 , p. 30.
- ↑ Cheke 1987b , p. 313.
- ↑ a b Cheke 1987b , p. 312.
- ↑ a b c Bretagnolle et al. 2000a , pp. 13-15.
- ↑ Cheke 1987b , p. 301.
- ↑ Cheke 1987b , pp. 312-314.
- ↑ a b Clouet 1978 , p. 99.
- ↑ Bretagnolle et al. 2000a , p. 12.
- ↑ Jones 1989 , p. 22.
- ↑ Barau et al. 2005 , p. 111.
- ↑ Clouet 1978 , pp. 100-102.
- ↑ a b Simmons 2000 , p. 25.
- ↑ Roussin 1878 , p. 294.
- ↑ Bretagnolle et al. 2000a .
- ↑ Bretagnolle et al. 2000b .
- ↑ a b c BirdLife International 2011 . Retrieved March 20, 2011.
- ↑ Simmons 2000 , p. 21.
- ↑ Cheke & Hume 2008 , p. 296.
- ↑ Mourer-Chauviré et al. 2004 , p. 168.
- ↑ Cheke 1982a , p. 36.
- ↑ Cheke 1982a , pp. 26-27.
- ↑ Bretagnolle et al. 2000a , p. 17.
- ↑ Cheke 1987b , p. 324.
