Shoebill
| Shoebill | ||||||||||||
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Shoebill ( Balaeniceps rex ) in the bird park Walsrode |
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Balaenicipitidae | ||||||||||||
| Bonaparte , 1853 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Balaeniceps | ||||||||||||
| Gould , 1850 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Balaeniceps rex | ||||||||||||
| Gould , 1850 |
The shoebill ( Balaeniceps rex ), also Abu Markub ( Arabic: "father of the shoe"), is an African bird that used to be assigned to the walking birds , today the Pelecaniformes . The bird, named after its powerful beak, is a resident of swamps . Since its morphology is unique, it is assigned to its own family, the Balaenicipitidae .
features
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The shoebill owes its name to the shape of its beak , which is extraordinarily long, but also very deep and wide. The beak length of a dude bird was 22.86 cm, the beak depth was 12.08 cm and the beak width was 10.16 cm. In the individuals measured accordingly, the beak length roughly corresponded to the beak circumference. One individual brought it to a beak length of 24.5 cm.
This beak is unique in the bird world. The upper beak resembles that of the pelicans; it is sharply edged and has a hook-like tip. This allows him to hold on to slippery prey or cut them up. The head is also very large and relatively broad. The neck, on the other hand, is relatively short compared to storks and herons. Standing upright, the shoebill reaches a height of 1.20 m.
The long legs end in extremely long toes, which distribute the weight over a large surface and thus prevent sinking. The wide wings allow a powerful flight with extended gliding phases. In flight, the head is placed on the shoulders like pelicans, since an outstretched neck would not be advantageous with the weight of the beak.
The plumage is bluish gray, only the belly is colored white. There is no gender dimorphism .
distribution and habitat
The shoebill is most common in southern South Sudan . In addition, it is found mainly in Uganda , Tanzania and Zambia as well as in isolated occurrences in some of these neighboring states. Its habitat are swamps and lake shores that are densely covered with papyrus or reeds . Since it rarely ventures out of the reed beds, it is rarely seen. Within the thicket, it moves mainly on narrow aisles that have been cleared by hippos or waterbucks .
Way of life
activity
Often a shoebill remains motionless for a long time. Apart from the moment of catching prey, his entire behavior is characterized by slow and deliberate movements. Although he can fly without any problems, he rarely uses this ability.
Shoebills are diurnal loners.
nutrition
The main food of the shoebill is made up of fish, especially African lungfish , pike and tilapia . Frogs, lizards, turtles and snakes make up a smaller proportion of the food spectrum. Other prey such as water birds and small mammals are documented, but seem to be rare exceptional cases.
When catching prey, the shoebill stands motionless, the beak pointing downwards. When a fish is sighted, the head pokes down. This hit takes less than a second. Since the balance is massively shifted forwards, the shoebill throws its head back in the next moment and supports itself with its wings on the ground so as not to fall over. The complexity of the procedure does not allow it to happen a second time in the event of failure. The prey is swallowed head first.
Reproduction
The nest is built in the middle of the swamps, either on solid ground or on floating islands of vegetation. Here plant material is piled up to form a small mound. As strict loners, the pairs of shoebills defend an area from 2.5 to 3.8 km² in size. One to three eggs are laid in the nest, which are initially bluish-white, but soon turn brown. An egg measures 8.5 × 6 cm in section.
Both partners brood. In order to prevent the clutch from overheating, it is regularly turned and doused with water. The birds fill their beaks with water four to five times a day to cool the eggs.
The young hatch after about 30 days. They wear a gray down dress and their beak is initially relatively small; it only begins to grow in the fourth week of life. Only after 100 days are the young, who are being fed by their parents during this entire period, fledged. Even at this age, they still have a relatively small beak, which is also pink instead of yellow. Because of the competition among the siblings for water and food, often only one of the chicks survives, usually the firstborn.
Systematics
The shoebill is usually assigned to the Balaenicipitidae family as the only species that has been placed in the order of the wading birds. Because of anatomical and ethological similarities, it was sometimes placed near the storks ; However, it is even more similar to the heron , as it has a comparable flight pattern , powder down and similarities in skeletal structure.
More recent molecular genetic analyzes suggest a completely different relationship, namely that the shoebill is descended from pelican-like ancestors and should therefore be placed in the order Pelecaniformes. In fact, this idea is very old: John Gould already expressed the theory when he first described the shoebill. The theory was reissued in 1957 by PA Cottam. Since then it has been discussed again and again by zoologists. Studies of the middle ear and eggshell structure led some scientists to believe that pelicans and shoebills must be closely related, while others suggested that all similarities were the result of convergent evolution . Thanks to the possibilities of modern, molecular genetic analyzes, the indications of a relationship between pelicans and shoebills increased. Sibley & Ahlquist even assigned the shoebill to the family Pelecanidae. In 2003, after a morphological analysis, Gerald Mayr also placed the shoebill close to the pelican relatives; he saw in it the sister taxon of all the species most gazed together at that time in the order of the coarse pods with the exception of the tropical birds. The taxon formed by the shoebill and the rudders is the sister taxon to the hammer head . SJ Hackett and co-authors as well as Fain and Houde classify the shoebill as a sister species of the pelicans in their revision of the bird system based on DNA sequence analysis . The sister group relationship to Hammerkopf was also confirmed.
According to the results of studies over the past twenty years, it has become questionable whether the shoebill could be attributed to the walking birds; classification in the Pelecaniformes or in their vicinity is widely accepted. The following cladogram clarifies the probable relationships that are also represented by the International Ornithological Union (IOU) at the time (2018).
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Shoebills and people
Because of ancient Egyptian sculptures depicting shoebill-like birds, there were speculations that the shoebill might once have been spread along the Nile as far as Egypt .
The IUCN has classified the shoebill as endangered since 2004 . Whereas in 1997 the population was estimated at 12,000 to 15,000 individuals, more recent studies assume that there are 5,000 to 8,000 birds. Of these, at least 80% live in South Sudan. The stocks are declining mainly due to the destruction of the landscape. The swamps of the Sudd were massively drained and destroyed during the construction of the Jonglei Canal , which robbed more and more shoebills of their habitat.
literature
- Josep del Hoyo et al .: Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions, 1992, ISBN 84-87334-10-5 .
Web links
- Balaeniceps rex in the Red List of Threatened Species of the IUCN 2013. Posted by: BirdLife International, 2012. Accessed September 28, 2013.
- Videos, photos and sound recordings of Balaeniceps rex in the Internet Bird Collection
Individual evidence
- ↑ Wolfgang Fischer: The shoebill . The new Brehm library, 1970, p. 13.
- ^ John Gould : On a new and most remarkable form in Ornithology. Balaeniceps rex , Proc. Zool. Soc. London 19, 1851, pp. 1/2
- ↑ Gerald Mayr: The phylogenetic affinities of the Shoebill (Balaeniceps rex) . In: Journal of Ornithology 2003, No. 144, pp. 157-175
- ↑ Hackett et al .: A Phylogenomic Study of Birds Reveals Their Evolutionary History . Science 27 June 2008: Vol. 320. no. 5884, pp. 1763–1768 doi : 10.1126 / science.1157704
- ^ Fain, MG, & P. Houde. 2004. Parallel radiations in the primary clades of birds. Evolution 58: 2558-2573.
- ^ List of bird names in the IOU IOC World Bird List
- ^ Frank Gill and Minturn Wright: BIRDS OF THE WORLD Recommended English Names. Princeton University Press, 2006, ISBN 0-7136-7904-2
- ↑ BirdLife International (2007) Species factsheet: Balaeniceps rex , October 16, 2007