Yellow crown gardener
|Yellow crown gardener|
Yellow crown gardener (head profile and top of the head of the male)
|Rothschild , 1895|
The yellow-headed gardener ( Amblyornis flavifrons ), also called the yellow-headed bowerbird , is a species from the family of bowerbirds (Ptilonorhynchidae) and is a representative of the avifauna of New Guinea. Compared to the Chlamydera species found in Australia or the silky arboreal bird , this species, belonging to the genus Amblyornis, has been relatively little researched due to its poorly accessible distribution area. For almost 9 decades the species was thought to be lost, it was not until 1982 that Jared Diamond observed this species in the Foja Mountains. One ofBruce Beehler led the first recordings of this kind in 2005.
With a body length of up to 24 centimeters, the yellow crown gardener is one of the smaller representatives in the bowerbird family and is roughly the size of a small thrush. He is one of the species whose courtship behavior includes the construction of an arbor by the male. No subspecies are distinguished for this species.
Yellow crown gardeners are very long-lived and take several years to reach sexual maturity. Due to the intelligence they show when building their arbors, they are counted among the most intelligent of the birds. According to the IUCN, their stock situation is classified as safe ( least concern ).
So far, body measurements are only available for three male yellow-crowned gardeners. These reached a body length of up to 24 centimeters, of which 8.4 to 8.6 centimeters were on the tail. The beak length of these three specimens was between 2.7 and 3.75 centimeters. The weight is estimated at 120 grams.
The males have a dense reddish-brown plumage and a 10 cm long, metallic, shiny golden-orange crown, forehead and neck cap. Individual feathers of this hood have brown feather tips, the hidden feather base is blackish-brown. The wings and the upper side of the tail plumage is brown-olive. The chest, belly and under tail-coverts are cinnamon brown. The underside of the tail plumage is dark isabel. The beak is black, the iris is dark brown. The legs are dark.
The females do not have a bonnet and they resemble the Mohrenpitohui ( Pitohui nigrescens ), a kind of thick-headed species . The plumage of the female yellow-crowned gardener is grayish-olive. They also have a longer curved bill and the tail is slightly longer.
The yellow-crowned gardener has a very large repertoire of calls, including croaking, gurgling, clicking and gurgling sounds, as well as those that reminded observers of the noises of crumpling paper or shoveling gravel.
Like other bowerbirds, yellow-crowned gardeners imitate the bird calls of their surroundings. It has been found a Mimicking rust ear honeyeater ( Marl ochromelas ) Pale abdominal Dickichtschnäpper ( Peneothello cryptoleucus ) Gelbhaubenkakadu and Greis Crow ( Corvus tristis ).
The yellow-crowned gardener is endemic to the area of the Foja Mountains north of the Mambaramo Basin and west of the provincial capital Jayapura in northern western New Guinea . It extends over an area of 10,000 km² and is mostly uninhabited. The original plan was to build a dam in the area that would have flooded the entire area. However, the project was discontinued for financial reasons. In 1995 it was declared a nature reserve and only at the end of 2005 were over 40 animal and plant species discovered or rediscovered here.
The habitat of the yellow-crowned gardener are mountain rainforests, which are dominated by araucarias , lithocarpus , beeches and stone beeches . Yellow crown gardeners usually stay in the middle to lower treetop area. Apart from the arboriculture males, they rarely come to the ground.
The food spectrum of the yellow crown gardener has not yet been conclusively investigated. However, it mainly eats fruit, which it looks for in the treetops. Apart from two species of pigeon , the yellow-crowned gardener is the largest fruit-eating bird species in its range.
The males of the yellow-crowned gardener are polygynous , that is, they mate with several females. The female builds the nest on her own, incubates the nest on her own and raises the young birds on her own. The males woo the females by building arbors, which, like the column gardener and the other Amblyornis species, belong to the "maypole" type. It is a construction in which branches are joined around a thinner tree trunk or a tree fern. The resulting column of twigs around this trunk is the essential characteristic of this type of arbor. Compared to the cottage gardener and red-crested gardener belonging to the same genus , the arbor of the yellow-crowned gardener, together with the golden-hood gardener, is a comparatively simple construction.
The arbors are erected by the males on ridges of hills. The distance from one arbor to the next is around 500 meters.
Arbor construction and ornamentation of the arbor
The yellow-headed gardener uses a young tree or a tree fern with a height of 0.5 to 4 meters as the base of his maypole. Around this he adds branches about 20 centimeters long. The resulting tower has a height between 0.5 and 1.2 meters. At the base of the maypole he erects a moss platform that is about one meter in diameter. The edge of this moss platform is slightly raised. The male also removes all branches and leaves from the immediate area around the moss platform.
As with most arborebirds, the yellow-crowned gardener decorates his arbor. The jewelry consists of piles of blue, green and yellow fruits carefully sorted by color. They are placed on the moss platform. A painting of the arbor, which has already been observed in other species of bowerbirds, has not yet been noticed by the yellow-crowned gardener.
There is as yet no information on how much time a male of the yellow-crowned gardener spends near his arbor during courtship. The closely related males of the red hood and gold hood gardener each spend about half of the day near the arbor.
Until 2004 the courtship of a male of the yellow-crowned gardener was observed only once. The adult male held one of the blue fruits with which his arbor was decorated in its beak for a period of 20 minutes. At first there were sounds that Clifford and Dawn Frith compare to the sound that a large mammal makes when it crosses a loose gravel bed, then it alternately imitated the calls of other bird species. The male sat at the beginning in front of his arbor and then flew to a stand guard near the arbor. He responded to the approach of a female with a two-syllable whistle and then remained silent. The female changed his seat guard near the arbor several times, the male always kept its beak pointed at this female. The orange-yellow hood was ruffled and partly upright, so that the female was presented with the blue fruit against an orange-yellow background. Occasionally the male shook his head with quick sideways movements so that the feather bonnet trembled. There was no mating in this observed courtship. The male began to shout again after the female flew away.
Nest and clutch
Nothing is known about the breeding biology of the yellow crown gardener. Not even a nest of this type has yet been found.
Rediscovery and existence
Walter Rothschild described the yellow-crowned gardener in 1895 on the basis of 4 bellows discovered in a spring fashion shop in Paris. After that it remained long lost until Jared Diamond undertook an expedition to northern Papua in 1982 and rediscovered this species in the Foja Mountains north of the Idenburg River at an altitude of between 1000 and 2000 m.
Despite missing population surveys, the nature conservation organization BirdLife International classifies this species as “not endangered” ( least concern ).
In December 2005, an expedition led by the American ornithologist Bruce Beehler from the conservation organization Conservation International succeeded in taking the very first photos of the yellow-crowned gardener.
- John Alcock: Animal behavior , from the American. by Matthias Sauerland, Gustav Fischer Verlag, 1996, ISBN 3-437-20531-5 , pp. 295 and 322
- Bruce M. Beehler , Thane K. Pratt: Birds of New Guinea; Distribution, Taxonomy, and Systematics . Princeton University Press, Princeton 2016, ISBN 978-0-691-16424-3 .
- Bruce M. Beehler: Birds of New Guinea , 1986
- Jared Diamond : The third chimpanzee . S. Fischer Verlag, Frankfurt am Main 1994, ISBN 3-596-17215-2 .
- Jared Diamond: Rediscovery of the yellow-fronted gardener bowerbird. Science, 216, 431-434. doi : 10.1126 / science.216.4544.431
- Clifford B. Frith, Dawn. W. Frith: The Bowerbirds - Ptilonorhynchidae . Oxford University Press, Oxford 2004, ISBN 0-19-854844-3 .
- Mike Hansell: Bird nests and construction behavior , illustrated by Raith Overhill, Cambridge University Press, ISBN 0521017645 .
- Peter Rowland: Bowerbirds . Csiro Publishing, Collingwood 2008, ISBN 978-0-643-09420-8 .
- Amblyornis flavifrons inthe IUCN Red List of Threatened Species 2016.3. Listed by: BirdLife International, 2012. Retrieved April 17, 2017.
- BirdLife International: Species Factsheet - Amblyornis flavifrons
- Bowerbirds: When animals become artists of illusion Pictures for building nests (Spiegel Online)
- Photo of the male
- Handbook of the Birds of the World zum Rothaubengärtnerl , accessed on April 17, 2017
- First photo of the yellow-crowned gardener from 2005 , accessed on April 18, 2017
- Frith: The Bowerbirds - Ptilonorhynchidae . P. 299.
- Beehler & Pratt: Birds of New Guinea . P. 278.
- Frith: The Bowerbirds - Ptilonorhynchidae . P. 298.
- Frith: The Bowerbirds - Ptilonorhynchidae . P. 297.
- Hansell: Bird nests and construction behavior , p. 195
- Frith: The Bowerbirds - Ptilonorhynchidae . P. 282.
- Frith: The Bowerbirds - Ptilonorhynchidae . P. 288.
- Jared Diamond in National Geographic . Retrieved November 13, 2016.
- "Lost World" of New Species Found in Indonesia . 2006. Retrieved November 13, 2016.