Hafferblaurabe
| Hafferblaurabe | ||||||||||||
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Hafferblaurabe ( Cyanocorax hafferi ) |
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| Scientific name | ||||||||||||
| Cyanocorax hafferi | ||||||||||||
| Cohn-Haft , Santos Junior , Fernandes , & Ribas , 2013 |
The Hafferblaurabe ( Campina Jay ) is a songbird art from the family of corvids (Corvidae). They are about 33 cm long, blue birds with a black face mask, bushy head and the typical habitus of South American blue ravens ( Cyanocorax ). The distribution area of the species extends over the region southwest of the Brazilian Manaus to the Bolivian border. Their habitat consists of rainforest and semi-open campinas , which form the transition to the savannah . The food of the Hafferblauraben consists of fruits, seeds and arthropods . Usually the birds move in small groups through the branches of trees and bushes. The breeding season of the species is in the dry season between July and September; The Hafferblaurabe builds its nest mainly in small forest islands.
The Hafferblaurabe was in 2013 by a research group led by Mario Cohn-adhesive for a new population of cyanocorax between the Purus and the Rio Madeira erected . According to DNA analysis , they are genetically somewhere between lilac raven ( C. heilprini ) and black breast raven ( C. affinis ), and morphologically they resemble the lilac raven in particular. The number of fully grown individuals is estimated at 26,500. With a view to the limited range of habitats and a move away from strict protective measures by Brazilian environmental policy, the first descriptors classify the population as "endangered" ( vulnerable ). In particular, the expansion of the BR-319 federal road between Manaus and Porto Velho could encourage the deforestation of large parts of the species area and threaten the continued existence of the species.
features
Build and color
The oat blue raven is about 33 cm long and 172 g body weight (dimensions of the holotype ) a medium-sized blue raven , among the South American species it is one of the smaller. Its wing becomes about 158 mm long, the tail reaches a length of 153 mm. The barrel measures 49 mm, the beak of the species is 37 mm long. A noticeable sexual dimorphism between females and males could not be determined when looking at the dimensions.
The plumage of the species is characterized by a black face mask and a head of feathers of the same color, which extends from the nasal bristles to the forehead and is flattened on the sides. The face, chin, throat and upper chest are black, with the black color reaching just behind the eyes and also including the ear covers. The mask is interspersed with three small, sky-blue spots on both sides: a short strip of cheeks from the corner of the beak down, as well as two small areas above and below the eye. The top and back of the head, the nape of the neck, the upper back, the sides of the neck and the chest are azure blue. The back, wings and tail are colored cloudy gray-brown on the upper side and covered in places with a violet-bluish veil, which is particularly evident on the upper wing-coverts. In the female individuals examined so far, it is more pronounced than in the males, which indicates a possible sexual dimorphism. The tail is bounded by a thin, almost black subterminal band and an approximately 15–22 mm wide, cloudy white end band. On the underside, the sky blue of the breast turns into a light brownish gray towards the tail, on the belly it can still be seen as a bluish veil. The abdomen is cloudy white, whereas the under tail-covers are more yellowish. The undersides of the tail and wings are gray-brown in color like the upper sides, but without a bluish tint. The lower tail also shows a white end band.
Flight image and locomotion
The Hafferblaurabe moves actively in all areas of the forest, jumping from branch to branch or taking short flights from one tree to the next. Like all blue ravens, the species is characterized by its relatively short, rounded wings and rapid, largely noiseless wingbeats. The birds only occasionally occupy sitting areas in the upper crown area and usually only linger briefly in one waiting area before moving on to the next.
Vocalizations
The vocabulary of the species is extensive and varied. The Hafferblaurabe has many different, predominantly monosyllabic calls, most of which have a whistling character. The most common utterance is a sharp whistled tjiu , which the birds repeat, often in a series of two or three. It is probably used for coordination in the group and, among other things, indicates dangers. In the course of the repetition it can change into a similar sounding mju . Since there is a wide range of variation between individual individuals and calls, the various other metallic and whistling calls cannot be clearly categorized. All in all, the sound repertoire of the Hafferblauraben is very similar to that of the Lilac Blauraben ( C. Heilprini ), from which it cannot be clearly distinguished in recordings.
Spreading and migrations
All sightings of the Hafferblauraben are concentrated in a region of around 190,000 km² southwest of the Brazilian city of Manaus . In the south-east it is bounded by the Rio Madeira , which - as with other blue raven species - represents a decisive biogeographical barrier. To the east of the river is the distribution area of the capped blue raven ( C. chrysops ), which occupies corresponding habitats there. The hypothetical distribution probably extends southward to the border region with Bolivia , where the foothills of the Andes offer changed vegetation. The Artareal extends along the Andes until shortly before Boca do Acre and fills the plains bordered by the Rio Purus . Further to the northeast, it crosses the river in one of its extensive loops, as suggested by a sighting west of the Rio Purus. In a north-easterly direction, the distribution limit follows its course more or less, the northern distribution limit is likely to run about 100 km south of Manaus. So far, the species has only been detected in the state of Amazonas . At least in the past, there was also a suitable habitat in the neighboring Rondônia . The agricultural change in the regional vegetation makes an occurrence there appear questionable, since the corresponding areas have since been significantly reduced. Model calculations produced a total area of 1090 km² for potential breeding habitat.
Outside the breeding season, the Hafferblaurabe apparently undertakes extensive migrations through the forests of the region; at least this suggests the low genetic diversity within the population.
habitat
The Hafferblaurabe lives in the transition zones between the savannah and the closed rainforest. The type of vegetation, the so-called Campina , is characterized by 3–8 m high trees in semi-open communities. In western Brazil it is typically formed by clusias ( Clusia spp.), Pagameas ( Pagamea spp.) And the palm species Mauritiella armata and Mauritia carana . At least outside the breeding season, the species can also be found in the closed terra firme forest that borders the Campinas. During breeding, however, it is strictly tied to this type of vegetation: the ostrich raven is absent wherever regular field fires decimate the Campina and only leave savannah and forest behind. The surrounding savannahs are primarily characterized by their characteristic as seasonal alluvial land during the rainy season. In contrast to the partly sympathetic hyacinth blue raven ( C. violaceus ), the oat blue raven does not occur in the Várzea , such as occurs along the Rio Purus.
Way of life
nutrition
According to stomach content analyzes, oat blue rabe is omnivorous and feeds on arthropods and seeds. In field observations, individual birds were seen carrying fruit in their beak and eagerly pecking at fruit stands. When eating, the animals move through trees and bushes, many food objects are probably ingested in the branches.
Social and territorial behavior
The Hafferblaurabe lives in small groups of three to eight birds throughout the year. They probably represent family associations and are made up of a pair of parents and the young from past broods. Within the group, the birds communicate lively through vocalizations. The groups probably occupy a delimited territory and are usually a kilometer or more away from other groups.
Reproduction and breeding
The breeding season of the Hafferblauraben is between April and October. The nest is bulky-oval and 30–50 × 36–59 cm in size. It is erected in trees 2 to 9 m high and is between one and 6.5 m above the ground. They are almost exclusively built in small forest islands in the middle of the Campinas. The birds mainly use twigs for the nest platform and line them inside with plant fibers, which they get mainly from the Mauritia carana palm . The clutches include up to three eggs with a pinkish-brownish base color and brown speckles. During the breeding and nestling phase, the mother and the nestlings are fed by the male and the brood helper . The latter are usually offspring from the previous year's brood. So far, no information is available about the duration of the breeding and nestling period.
Taxonomy and systematics
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| Position of the Hafferblauraben within the light-eyed Blauraben according to Cohn-Haft et al. (2013). The species is very closely related to the black breasted raven and the lilac raven , its sister species is probably the lilac raven. |
In 2002 Mario Cohn-Haft observed an immature bird about 140 km south of Manaus, where no blue ravens have been found to date , which apparently belonged to the genus Cyanocorax . It was unclear whether it represented an area expansion of a known species of blue raven or should be placed in a new species, since the youth clothing of blue ravens is hardly documented or researched. Only after several expeditions in the following years could a few adult individuals be photographed and captured, which made morphological and genetic comparisons with other blue ravens possible. Mario Cohn-Haft and his colleagues Marcelo dos Santos Junior , Alexandre Fernandes and Camila Ribas were able to isolate consistent differences to similar blue ravens with regard to both the plumage drawing and the mitochondrial gene sequences . The taxonomic independence of the population between Purus and Madeira was also supported by their geographical isolation from other blue ravens. On this basis, Cohn-Haft and colleagues set up the new species Cyanocorax hafferi for them in 2013 . They dedicated the specific epithet to the biologist Jürgen Haffer , in order to honor his significant contributions to the biogeography of the South American avifauna . Cohn-Haft and his co-authors saw in Cyanocorax hafferi and the species related to it a prime example of the allopatric species groups in South America described by Haffer , whose individual species are often only separated from one another by individual river valleys or ridges.
The Hafferblaurabe is part of a blue raven radiation in Central and South America, which is characterized by light blue eyes and lowland habitats. Both in the plumage drawing and in the examined gene sequences, the species shows great similarities to the lilac ( C. Heilprini ) and black breasted raven ( C. affinis ), which occur southeast and northwest of the Cordillera Central . The genetic divergence to the lilac raven is 0.7%, to the black breast raven 1.8%, both values are low compared to the species. Although Cohn-Haft and colleagues were unable to construct a dichotomously branched cladogram for the three species, the closest relative of the Hafferblauraben seems to be the Lilac Blue Ravine. In addition to the lower divergence, this is indicated by the great similarity in coloration, common habitat preferences, a matching sound repertoire and the greater geographical proximity between the species areas. Cohn-Haft and colleagues suspect that the two populations separated within the last one million years.
Population and status
On the basis of field observations in representative areas of the distribution area, the population of the Hafferblauraben is estimated to be around 26,500 adult individuals. The area of 1,090 km² of the species, which can be considered as a breeding habitat, falls below the 2,000 km² criteria set by the International Union for Conservation of Nature and Natural Resources for the endangered status vulnerable (“endangered”). In 2016 the Hafferblaurabe was placed on the IUCN's warning list and classified in the near threatened category. Settlement and land use models for expressways in Amazonia also predict the complete disappearance of all breeding habitats for the region between Rio Purus and Rio Madeira in the next 30 to 50 years, should the region be better developed for car traffic. The repair of the BR-319 federal road since 2008 and the development along comparable expressways in Amazonia make such a scenario likely. Above all, the easier access to forest areas lead to increased settlement and commercial logging and thus to deforestation of large areas. This is increased by the conversion of the affected areas as pastures and their regular slash and burn. Against this background, Cohn-Haft and colleagues consider the criteria for the vulnerable status (expected sharp decline in breeding areas) to be fulfilled. The first protective provisions of the Brazilian authorities for the Campinas between Manaus and Porto Velho, which were issued in 2007, have since been weakened or completely withdrawn under pressure from the local economy. In addition, the lack of infrastructure and staff are likely to make it more difficult for nature conservation authorities to control the region.
swell
literature
- Elisa Bonaccorso, A. Townsend Peterson, Adolfo G. Navarro-Sigüenza, Robert C. Fleischer : Molecular systematics and evolution of the Cyanocorax jays . In: Molecular Phylogenetics and Evolution . tape 54 (3) , 2010, pp. 897-909 , doi : 10.1016 / j.ympev.2009.11.014 .
- Mario Cohn-Haft, Marcelo A. Santos Junior, Alexandre M. Fernandes, Camila C. Ribas: A new species of Cyanocorax jay from savannas of the central Amazon . In: Josep del Hoyo , Andrew Elliott, Jordi Sargatal, David A. Christie (Eds.): Handbook of the Birds of the World . Special volume . Lynx Edicions , Barcelona 2013, ISBN 978-84-96553-88-0 , pp. 306-310 .
- Marcelo Augusto dos Santos Junior: História natural e conservação do cancaozinho-da-campinã (Cyanocorax sp.), Recém descoberta e ameaçada ave endêmica da Amazônia Central, Amazonas, Brazil . Universidade Federal do Amazonas, Manaus 2008.
Web links
Individual evidence
- ↑ Cohn-Haft et al. 2013, pp. 306-307
- ↑ a b Cohn-Haft et al. 2013, pp. 307-308.
- ↑ a b Cohn-Haft et al. 2013, p. 309.
- ↑ Cohn-Haft et al. 2013, pp. 306-309
- ↑ a b Cohn-Haft et al. 2013, p. 308.
- ↑ a b c Cohn-Haft et al. 2013, pp. 308-309.
- ↑ Santos Junior 2008, pp. 49-51.
- ↑ Cohn-Haft et al. 2013, pp. 307-309.
- ↑ Bonaccorso et al. 2010, p. 903.
- ↑ a b Cohn-Haft et al. 2013, pp. 309-310.
- ↑ Santos Junior 2008, p. 36.