Gray dove bird
| Gray dove bird | ||||||||||||
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Gray dove bird |
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| Chlamydera nuchalis | ||||||||||||
| ( Jardine & Selby , 1830) |
The gray bower bird ( Chlamydera nuchalis ) is a species from the family of bower birds (Ptilonorhynchidae) and is a representative of the avifauna of Australia . Compared to the three-gang bowerbird , which only occurs in New Guinea , this species has been relatively well researched due to its distribution in Australia.
With a body length of up to 35 centimeters, the gray bower bird is the largest Australian representative in the family of bower birds and is one of the species of this family whose courtship behavior includes the construction of an arbor by the male. Unlike many bowerbirds, there is no sexual dimorphism .
Gray bower birds 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. The IUCN classifies the population of the gray bowerbird as safe ( least concern ). There are two subspecies.
features
Body measurements
Gray bower birds reach a body length of up to 35 centimeters, of which 12.7 to 16.5 centimeters are on the tail. The beak length is 3.2 to 4.15 centimeters. The males reach a weight between 180 and 265 grams, females remain slightly lighter at 152 to 215 grams.
Appearance of the males
The plumage of the gray bower bird is light gray-brown. Only the chin, throat, front chest and the top of the body are a little darker and grayer. The vertex is gray, the male has individual feathers on the rear vertex and the sides of the neck have silvery white feather tips, so that the head looks slightly spotted. In the male, the neck feathers are also somewhat elongated and from blue-violet to mauve in color.
The feathers of the large wing covers are dark brown and have pale feather tips. The arm and hand wings are lightened so that they are almost a dirty white color. The under tail-coverts are pale gray-brown and each feather has three to five darker transverse bands. The iris is dark brown, the beak is dark brown to black.
Appearance of females and fledglings
The female resembles the male, but with them the neck patch is either completely absent or less developed.
Young birds have a slightly darker plumage on the throat and chest than the adult birds. In the young males, the chest is also noticeably banded across. The young birds also have individual pale brown feathers in their back plumage.
voice
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The male's calls near the arbor include clicks, sibilants, and cat-like meows. Like many other bowerbirds, the gray bower bird is an excellent mocker. Among other things, it imitates dog leashes, machine noises, human voices and similar ambient sounds.
Brooding females as well as males near their arbor imitate the calls of predators. Among other things , there is evidence of the imitation of the calls of the wedge-tailed harrier ( Haliastur sphenurus ), Papuan harrier ( Aviceda subcristata ) and black kite . A female with two newly hatched cubs flew up, took cover in the bushes and imitated the calls of the Jägerliest and the blue-eared honey eater , known for reacting to predators with hatred when someone approached the nest. There is also other evidence for the targeted use of imitation sounds: A gray bower bird perched on a branch above a sleeping cat observed it and imitated meowing until the cat left the area.
Gray bower birds pick up sounds from their environment very quickly. A male near Townsville mimicked the calls of the wedge-tailed eagle , a rarity in the region. In this case, however, a pair of wedge-tailed eagles had repeatedly flown over the area in which the male was.
Distribution area and habitat
The gray bower bird inhabits the north of the Australian continent. The range extends in a wide band from the Kimberley over the Northern Territory to the north of Queensland , where the gray bower bird occurs from the Cape York Peninsula to the city of Mackay on the Australian east coast. It colonizes most of tropical Australia north of 20 ° south latitude. The altitude distribution ranges from the lowlands to altitudes of 600 meters. In a small part of its distribution area in the area of the Cape York Peninsula, the gray- bellied bird overlaps with the brown-bellied bowerbird . Together with the drip bower bird , the gray bower bird is the only species of bower bird that also occurs in the west of the Australian continent. The drip arborvird, however, inhabits much more arid regions than the gray arborvature bird.
Two subspecies are distinguished in the distribution area:
- C. n. Nuchalis (Jardine & Selby, 1830) - Occurring from northwest Australia across the Northern Territory to the extreme northwest of Queensland. The nominate form of the gray bower bird also colonizes numerous islands off the Australian coast, including Melville Island and Groote Eylandt .
- C. n. Orientalis (Gould, 1879) - Compared to the nominate form, the range of this subspecies is small. It occurs only in Queensland and inhabits a large part of the Cape York Peninsula, the range extends south to the city of Mackay. Females of this subspecies are somewhat more transversely banded and the upper plumage is somewhat more contrasting in both sexes.
The habitat of the gray bower bird are the fringes of tropical rainforests, lianas, forest areas along rivers, open savannahs, eucalyptus and myrtle heather forests , mangrove areas and gardens. In general, the gray dove bird can never be found far from water, as the food plants it prefers are water-dependent. The gray bower bird does like to bathe, but is not dependent on water points to cover its fluid requirements. Unlike other songbirds, it does not go to watering places even in dry seasons.
food
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The gray foliage bird eats mainly fruits, while the fruits play the fig species Ficus benjamina , Ficus platypoda and Ficus racemosa a special role. It also eats the fruits of the natural palm Carpentaria acuminata, which is found only in tropical Northern Australia . He drinks nectar, especially from Grevillea pteridifolia , a species from the Greville family, and he eats flowers, although he has a preference for red or purple flowers. In addition, plants introduced in Australia also play a role in his diet today. He has a particular fondness for the fruits of the neem tree and the Netzannone .
He eats animal protein in the form of spiders and ants. It also eats grasshoppers and stink bugs . Beetles, caterpillars and larvae. In Townsville in the 1970s, there were gray bower birds who opened the caps on milk bottles to drink the topped cream. Occasional eating of chicken eggs is also documented .
Reproduction
The males of the gray bower 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 with the construction of arbors, which, like the silky-bowerbird , the sericulus species and the other species of the genus Chlamydera, belong to the "avenue" type. As with other species of bowerbird, this arbor is adorned with decorative objects and the walls of the arbor is partly painted.
arbor
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The arbors of the gray bower birds generally have a north-south orientation. The bird erects two walls of thin twigs along a platform made of twigs. The male contributes between 4,000 and 5,000 branches to create a complete arbor. A male observed carried an average of 90 branches and 28 glass fragments used as decorative objects to the arbor per hour. According to observations, males need about three weeks at the beginning of the courtship season to rudimentarily complete the arbor. They then add to their arbor throughout the entire courtship period.
The walls of the arbors are built so that the branches lean inwards. In 54 arbors that were examined in the area of Townsville, 30 percent of the tips of the small branches built into the walls touched the walls above the corridor. In just under 10 percent, the middle aisle had a roof. In a further 30 percent, only about 10 percent of the built-in branches touched in the middle.
In the case of incompletely built or poorly built arbors, these usually come from male young birds that are still practicing arbor building. In one case, an arbor of the gray bower bird was found, which deviated from the basic principle and in its shape was reminiscent of the complex arbors of the three- aisle bowerbird , as the central aisle was short and two more walls were built at the end of the central aisle. If the two walls had been connected, they would have framed the arcade center aisle in a semicircle. This arbor has so far represented the greatest deviation from the respective species-specific construction that has so far been found in arborebirds.
Decorating the arbor
Gray bower birds are among the bower birds that decorate their arbors very elaborately. The decorative objects used include snail shells, small bones of mammals, a few green fruits and / or leaves and some red decorative objects. They are usually placed in the courtship area in front of the central aisle. In individual cases, up to 900 snail shells were piled up in front of the entrance to the arbor. The jewelry used in 28 arbors examined near Darwin weighed between 6.2 and 12.1 kilograms. The individual objects each weighed between 2 and 40 grams.
Man-made objects are also used for decorating. In nine of the arbors examined in Townsville, the males had hung white plastic rings that came from plastic bottles in the branches of the walls. Paper clips, pens and other office supplies were found in an arbor near Townsville University Campus. Ammunition cases were also installed in arbors near military sites.
Red ornaments are not found on all arbors, but they were found on the particularly carefully built arbors during the investigation in Townsville. Only very few red jewelry objects were ever installed and these were never in the center aisle or in front of the southern end.
Nest, clutch and rearing of the young birds
Nests with eggs or fledglings were found in all calendar months except April and June. The females build their nests in trees, Bauhinien are particularly preferred nesting trees. Nests have also been found in Caesalpinias , Eucalyptus alba and the apple and pear trees that are exotic to Australia. Females use nesting sites repeatedly, but then build a new nest. The clutch consists of one or two eggs. The breeding season averages 21 days.
Gray dove bird and people
The location of the type specimen that was used to scientifically describe the gray dove bird for the first time is unknown. It is believed that it originated in the region around Port Darwin in the Northern Territory. The specific epithet nuchalis is derived from the Latin term for neck and alludes to the purple nape of the neck of the species. The C. n. Orientalist subspecies was collected near Bowen .
hybrid
Wherever the range of individual species of bowerbirds overlap, natural hybrids occasionally appear. The area of distribution of the spotted arborebird overlaps to a small extent along the Cape Rlvers with the gray bowerbird . Various natural hybrids have been observed between the two species.
literature
- 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 .
- Clifford B. Frith, Dawn. W. Frith: The Bowerbirds - Ptilonorhynchidae . Oxford University Press, Oxford 2004, ISBN 0-19-854844-3 .
- Peter Rowlalnd: Bowerbirds . Csiro Publishing, Collingwood 2008, ISBN 978-0-643-09420-8 .
Single receipts
- ↑ a b c d Handbook of the Birds of the World zum Graulaubenvogel , accessed on April 8, 2017
- ↑ Rowland: Bowerbirds . P. 91.
- ↑ a b c d e Frith: The Bowerbirds - Ptilonorhynchidae . P. 427.
- ↑ Frith: The Bowerbirds - Ptilonorhynchidae . P. 425.
- ↑ Frith: The Bowerbirds - Ptilonorhynchidae . P. 423.
- ↑ a b Frith: The Bowerbirds - Ptilonorhynchidae . P. 424.
- ↑ a b c Rowland: Bowerbirds . P. 94.
- ↑ a b Rowland: Bowerbirds . P. 93.
- ↑ a b Frith: The Bowerbirds - Ptilonorhynchidae . P. 426.
- ↑ a b Frith: The Bowerbirds - Ptilonorhynchidae . P. 428.
- ↑ a b c Frith: The Bowerbirds - Ptilonorhynchidae . P. 429.
- ↑ a b Frith: The Bowerbirds - Ptilonorhynchidae . P. 430.
- ↑ Frith: The Bowerbirds - Ptilonorhynchidae . P. 433.
- ↑ Frith: The Bowerbirds - Ptilonorhynchidae . P. 434.
- ↑ Frith: The Bowerbirds - Ptilonorhynchidae . P. 405.
Web links
- Video: Chlamydera nuchalis (Ptilonorhynchidae) - courtship and copulation . Institute for Scientific Film (IWF) 1967, made available by the Technical Information Library (TIB), doi : 10.3203 / IWF / E-1079 .
- Video: Chlamydera nuchalis (Ptilonorhynchidae) - handing out collection pieces at the arbor . Institute for Scientific Film (IWF) 1967, made available by the Technical Information Library (TIB), doi : 10.3203 / IWF / E-1078 .