Cottage gardener
| Cottage gardener | ||||||||||||
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Cottage gardener with arbor in the background |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Amblyornis inornata | ||||||||||||
| ( Schlegel , 1871) |
The Cottage Gardener ( Amblyornis inornata ) is a kind from the family of Bowerbirds (Ptilonorhynchidae) and is a member of the avifauna of New Guinea. Compared to the Chlamydera species occurring in Australia or the silky bower , this species has been relatively poorly researched due to its less accessible range.
With a body length of up to 25 centimeters, the hut gardener is one of the smaller members of the bowerbird family and is roughly the size of a thrush. It is one of the species whose courtship behavior includes the construction of an arbor by the male. In contrast to many bower birds, there is no noticeable sexual dimorphism . So far, no subspecies have been distinguished for this species, but the populations in southwest New Guinea with their somewhat different arbor structure may represent a subspecies.
Cottage 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 ). They are common in their area of distribution, but often only to be identified by their calls.
features
Appearance
Cottage gardeners reach a body length of up to 25 centimeters, of which 8.5 to 10.4 centimeters are on the tail. The beak measures between 2.7 and 3.3 centimeters. Adult cottage gardeners weigh between 105 and 155 grams.
The parting is dark maroon, the sides of the head are pale olive in color. The feathers on the chin have gray to gray-brown feather edges, which makes this part of the body look slightly scaled. The top of the body is dark olive to cinnamon brown. The underside of the body is isabel to pale cinnamon. The sides of the body are a little darker. The under tail coverts are isabel colored. The control springs are olive-colored with white spring shafts. During the breeding season, the legs of the males are deep blue. This shade of blue is a little less pronounced in males and females that are not yet sexually mature. The beak is blackish with a bluish beak base. The iris is dark brown.
Unlike other species of the genus Amblyornis , the males of the hut gardeners do not have a conspicuous colored hood that stands out from the rest of the plumage. The hut gardener's young birds cannot be distinguished from adult hut gardeners by their plumage.
Calls and sounds
The cottage gardener has a broad repertoire of calls , including whistling tones, chuckling and sharp clicks, kah kah calls or keu keu keu keu series repeated several times and tones that make people gasp or remind them of spitting. Hut gardeners, who were observed more closely in the Arfak Mountains for three weeks, preferred to call in the early morning and late evening hours.
As is typical for a majority of the bowerbirds, the hut gardener imitates other bird calls as well as ambient sounds. The most frequently imitated bird calls include those of the Arfak ray paradise bird ( Parotia sefilata ) and the gray-bellied fan-tail ( Rhipidura albolimbata ). Other identified species that the cottage gardener imitates are the slate thicket flycatcher ( Peneothello cyanus ) and the forest thickhead ( Colluricincla megarhyncha ). The hut gardener also imitates the sounds of the palm cockatoo , although these two species hardly overlap in their height distribution.
Ambient sounds that the hut gardener picks up include the chopping of wood, barking dogs, the sound of tent walls flapping in the wind and generators.
Distribution area and habitat
The cottage gardener occurs in western New Guinea. Although its common English name is Vogelkop Bowerbird , its range is not limited to the Vogelkop , a peninsula in the far northwest of New Guinea. The distribution area is disjoint , at least four non-contiguous regions in western New Guinea are populated.
On the Vogelkop, the hut gardener populates the Tamrau Mountains in the northwest and the Arfak Mountains in the northeast, separated by the Kebar Valley . In the Arfak Mountains , the hut gardener occurs at altitudes between 1200 and 2000 meters, in the Tamrau Mountains, on the other hand, between 1460 and 1830 meters. Further northeast of the Vogelkop Peninsula, they occur in the Wondiwoi Mountains on the Wandammen Peninsula (elevation range 1160 to 2075 meters).
Two other distribution areas are in southwest New Guinea. Cottage gardeners populate mountains in the Fakfak administrative district , where it occurs between 1000 and 1300 meters above sea level, and the Kumawa Mountains . What is striking about these populations is that they are outwardly indistinguishable from the populations further to the north and north-west. The shape of their arbor differs from these populations, however, and is more like the arbor of the golden hood gardener . It has not yet been clarified whether this deviating arbor construction applies to all hut gardeners in southwest New Guinea and what breadth of variation is typical for the populations in the northwest. However, the hut gardener's southwest populations may represent a subspecies of their own.
The hut gardener's habitat is tropical rainforests with treetops at heights of 25 to 30 meters above the ground.
food
The eating habits and the food spectrum of the hut gardener have so far only been rudimentary investigated. The findings of numerous seeds under the raised hide in the vicinity of their arbors indicate that hut gardeners mainly feed on fruits and berries. Cottage gardeners have also been seen eating fruits 1 to 2.5 centimeters in diameter. They also eat insects: a cottage gardener has been seen catching an insect in flight and they also eat the flies that are attracted by rotting mushrooms.
Life expectancy
The life expectancy of cottage gardeners or their mortality rate has not yet been investigated.
Social behavior
Adult hut gardeners live as solitary animals and only come together to mate, with the males busy with their arbor for most of the year. After they have fully fledged, the male, young hut gardeners stay close to the adult males for a certain time and watch the craft of building arbors.
Reproduction
The hut gardener's males are polygynous , which means that 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. While the arbors of gold cap and yellow crown gardeners are comparatively simple constructions, the column gardener builds a comparatively elaborate arbor of the maypole type. The hut gardener is, together with the red-hood gardener, the species in which at least the north-western population builds the most complex arbor of this type. As with other species of bowerbird, this arbor is adorned with decorative objects.
There is no information on how long it takes an adult cottage gardener to build an arbor and whether he will occupy it for several years. However, there is evidence that males defend an arbor for several years. It is not yet clear whether younger males will take over existing arbors when the arbor owner dies.
In a population in the Arfak Mountains that was observed over three weeks, the males spent about 50 percent of the daytime in close proximity. They spent a small part of the time singing near their arbor. During the vast majority of their presence at the arbor, they were busy rearranging the decorative objects of their arbor, procuring new material for the arbor construction or decoration, or repairing the arbor.
Arbor construction of the southwest populations
During his expeditions to New Guinea in the 1980s, Jared Diamond discovered that the populations in the Kumawa Mountains consist only of a single central maypole and thus differ significantly from those of the north-western populations, who build a hut-like roof over a low maypole.
The tree trunk on which the maypole is erected is typically three to six meters high and one to three centimeters in diameter. It is typically up to a tree trunk height of 1.5 to four meters without any leaves. The maypole that is erected on this tree trunk stands on a platform made of dried, brown moss and has an average height of two meters. The maypole is usually 50 centimeters in diameter at its lower end and 25 centimeters at its upper end.
The twigs and stems built into the maypole are between 20 and 90 centimeters long. According to Jared Diamond, the hundreds of branches or stems are attached with a whitish adhesive, the origin of which is unknown. Deviating from this, Clifford and Dawn Frith are of the opinion that it is not an adhesive applied by the male, but that the whitish mass is a matter of fungi that quickly colonize the humid tropical climate. According to her studies on other species of the genus Amblyornis , the male lays the branches on top and inserts them between the other branches with slightly shaking head movements.
The moss platform is built almost perfectly circular around this maypole and has a height of nine to 15 centimeters in the middle. Jared Diamond estimated the weight of the moss built in this way to be several kilograms. The dried up brown moss platform is painted glossy black. According to Jared Diamond, the male uses his own feces as a dye. He had found that the gardener's droppings were comparatively fluid, oily in consistency and black in color from the birds he had caught. The color is otherwise not to be found in the living space of these cottage gardeners. According to Clifford and Dawn Frith, the black color is caused by a mixture of saliva and bits of coal. They argue that the male usually leaves the arbor to defecate and visits a preferred stand guard not far from the arbor.
Jared Diamond noted that another difference between the two populations was that the males of the southwestern population proved to be extremely shy and in this behavior, too, differed significantly from the very trusting populations on the Wandammen Peninsula. This behavior is all the more noticeable as it can be safely assumed that the males had never met humans in this remote region of New Guinea.
Arbor construction of the northwest populations
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The arbors of the northwest populations follow the principle of a central maypole that is built between tree shoots. However, the maypole is covered by a hut-like roof with an opening to a large central threshing floor. In the Arfak Mountains, these entrances measured between 18 and 38 centimeters and were between 20 and 28 centimeters high. A few arbors found in the Arrak Mountains also had a second, smaller entrance in the arbor roof. The central element is often 60 to 90 cm high and the floor area measures up to 1.5 m in diameter. A particularly large arbor in the Tamrau Mountains was supported by two tree saplings and covered an area of 3 by 2 meters. The height was 1.5 meters.
Stems of epiphytic orchids are mainly used. However, individual arbors have also been found that were built entirely from bear moss ferns , which gives the arbor a very atypical appearance. The interior and the forecourt are finely cleaned and covered with moss brought by the hut gardener . The platform of the maypole is green moss and not dried out, brown like in the southwestern population. The moss platform is typically 20 to 23 centimeters in diameter and 15 centimeters high. A painting of the moss, as is typical for the southwestern population, is missing. The maypole also lacked the glue that held the boxes together.
Decorating the arbor
Decorating and painting the arbor can be found in many species of bowerbirds, so the hut gardener has a behavior that is typical for this family. They collect flowers, feathers, fruits, insect wings, resin , berries and mushrooms to decorate their arbor. Most of the decorative objects used are things that are common in the cottage gardener's living space. Man-made objects that can be found on the arbors of, for example, the drop arborebird or the gray bowerbird are rare among the cottage gardeners who live in the very remote mountain regions of New Guinea. However, a sardine can for an arbor was a central decorative object that was placed on the moss platform for at least seven years. A large number of empty ammunition cases were found in another arbor. The males decorate their arbor again and again. After such actions, they fly to stand waiting in the immediate vicinity of the arbor and from there examine the effect that was achieved by the redecoration, then return to the arbor to either reposition it or leave it in place.
Similar to the construction of the arbor, there are also differences in decorating the arbor in the two different north and south-western populations. However, it is common to both populations that they frequently redecorate their arbors.
Foliage decorations in the north-western populations
The southwest populations who only build a maypole often lean the large leaves of screw trees against the lower end of the maypole. The leaves measured between eight and sixty-five inches and weighed between 15 and 60 grams, which is considerable weight for a bird weighing between 105 and 155 grams who had carried or dragged these leaves to the hut. Outside the moss platform there are numerous decorative objects that are carefully sorted and separated in separate piles. These are usually several hundred snail shells, as well as brown acorns, a small number of black-painted branches and a few beetles. The jewelry objects weighed around 3 kilograms.
Foliage decorations in the southwest populations
The northwestern populations trimmed their bowers primarily with black stielporlingsartigen mushrooms , with dark brown or black wing covers of beetles, blue, orange and red fruits and red fruits. Jared Diamond offered different colored poker chips to the males he examined on the Wandam Peninsula. Even if individual preferences differed slightly, the preferred colors were blue, orange and purple followed by red, yellow, lavender and white. The males mostly assigned these chips to natural objects of a similar color. Colors that turned out to be preferred in the experiment were more likely to be laid out inside the arbor. The males placed blue chips in the hut 96 percent of the time, compared to only 58 percent of the yellow chips.
Competitive behavior and reproductive success
On the basis of the observations he made, Jared Diamond came to the conclusion that not yet sexually mature males regularly visit the arbours of adult hut gardeners and are then chased away by them. In addition to chasing away conspecifics, arbor owners are also aggressive towards other bird species. Among other things, there is evidence of the chasing away of black fan tails ( Rhipidura atra ), striped honey eaters ( Ptiloprora perstriata ) and a coral downy pigeon , which are similar in size to the hut gardener. Hut gardeners showed no aggressive behavior towards larger bird species such as the broad-tailed paradise hop ( Epimachus fastosus ).
During his expedition in New Guinea, Jared Diamond targeted the owners of cottage gardeners' arbours. After a period of just two hours, conspecifics pulled branches out of the maypole and removed screw tree leaves. Over the next two days, damage to the arbors increased. Diamond was also able to prove with identifiable jewelry objects that males stole decorative material from other arbors and used it to decorate their own arbors.
In 16 observed arbors in the Arfak Mountains, only eight of the males were mated. The three most successful males accounted for 60 percent of all matings. They differed from the unsuccessful males by the size of their arbor and, compared to the other males, had built in more blue decorative objects.
Pair formation and courtship
If a female comes near the arbor, the male interrupts the arbor construction and tries to arouse interest even more with his song. When the female enters the forecourt to examine the arbor more closely, the male retreats into the arbor or sometimes presents some of his decorations. Once the female has chosen the male, they mate directly by the arbor. While the females usually only mate with one partner, the males are polygamous , i. that is, they try to copulate with as many females as possible. Some manage to mate with up to 20–33 different females in a single mating season. But most of them fail completely because their arbors do not meet the demands of the females. These choose males with large, magnificent arbors, as they characterize them as strong and healthy.
The male birds do not contribute to the incubation and rearing of the young. After mating, the females devote themselves to building nests in order to hatch the eggs and raise the young. The males stay with their arbor.
Nest, brood and rearing of the young birds
After mating, the females build their own simple, trough-shaped nest with a diameter of 15 cm, which they build in the treetops at a height of 1.8 to 3 m. The details of brood care and the breeding season have not yet been investigated.
Cottage gardeners and people
According to reports, a pair of cottage gardeners were imported into Great Britain in 1909. Other reports of husbandry are not available.
The indigenous peoples near the Arfak Mountains set great store by not destroying the hut gardeners' arbours.
literature
- 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 .
- Jared Diamond : The third chimpanzee . S. Fischer Verlag, Frankfurt am Main 1994, ISBN 3-596-17215-2 .
- 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 .
Web links
- Animal Behavior (PDF; 542 kB); Volume 33, Issue 1, February 1985, Pages 266-271
- Uwe Georg, Art in Architecture - On the trail of the wondrous bowerbirds (PDF; 219 kB); Geo - the new image of the earth; No. 11 / 02/11
- BBC Nature - video material on arbor construction
- www.arkive.org - Collection of pictures and videos from the cottage gardener
- Amblyornis inornata on the 2012 IUCN Red List of Threatened Species. Listed by: BirdLife International, 2012. Retrieved January 24, 2013
- www.xeno-canto.org - sound recordings for the hut gardener
Single receipts
- ↑ a b Handbook of the Birds of the World zum Hüttengärtnerl , accessed on April 13, 2017
- ↑ a b c d e f g Frith: The Bowerbirds - Ptilonorhynchidae . P. 292.
- ↑ a b Beehler & Pratt: Birds of New Guinea . P. 279.
- ↑ a b c d Frith: The Bowerbirds - Ptilonorhynchidae . P. 296.
- ↑ Frith: The Bowerbirds - Ptilonorhynchidae . P. 291.
- ↑ a b Frith: The Bowerbirds - Ptilonorhynchidae . P. 290.
- ↑ Rowland: Bowerbirds . P. 115
- ↑ a b c d e f g Frith: The Bowerbirds - Ptilonorhynchidae . P. 293.
- ^ Hansell: Bird nests and construction behavior . P. 195.
- ↑ a b c d e f g Frith: The Bowerbirds - Ptilonorhynchidae . P. 295.
- ^ A b c d Hansell: Bird nests and construction behavior . P. 197.
- ↑ a b Frith: The Bowerbirds - Ptilonorhynchidae . P. 294.
- ^ Hansell: Bird nests and construction behavior . P. 198.
- ^ Hansell: Bird nests and construction behavior . P. 199.