Golden glasses bird

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Golden glasses bird
Golden glasses bird

Golden glasses bird

Systematics
Order : Passerines (Passeriformes)
Subordination : Songbirds (passeri)
Superfamily : Sylvioidea
Family : Spectacled birds (Zosteropidae)
Genre : Cleptornis
Type : Golden glasses bird
Scientific name of the  genus
Cleptornis
Oustalet , 1889
Scientific name of the  species
Cleptornis marchei
(Oustalet, 1889)

The golden- rimmed bird ( Cleptornis marchei ) is a songbird species from the spectacled family (Zosteropidae). The species is restricted to the islands of Saipan and Aguijan of the Northern Mariana Islands . The gold-rimmed bird has gold-colored plumage and a pale eye ring and feeds on insects , fruits and nectar. The genus Cleptornis is monotypical . Formerly the golden white-eye has been in the family of honeyeater found (Meliphagidae) and therefore gold Honigfresser called recently but its membership of the spectacle birds is considered certain. The exact position of the golden-rimmed bird within the family has not yet been clarified.

Its range overlaps with that of the rein-goggle bird . Fossil finds show that the golden-eyed bird was once widespread on the islands of Tinian and Rota , but was exterminated there by human hands. Although the golden-rimmed bird is currently still extremely common on Saipan and Aguijan and has the highest recorded distribution density of all birds, the species is nevertheless critically endangered . The invasive brown night tree snake , which has been introduced to Saipan in recent years, poses a particular threat . It is believed that the predator will cause a sharp decline in the golden-rimmed bird population if not controlled. Efforts are now being made to curb the spread of the snakes and to breed the birds in captivity.

Taxonomy

The species was originally called "golden honey eater " because it was believed to belong to the honey eater (Meliphagidae). The French naturalist Émile Oustalet assigned the species to the genus Ptilotis within the honeyeater family when he wrote the first description in 1889. However, this genus is now invalid and no longer in use. Later the species was placed in the genus Cleptornis , which was established by Oustalet in the event that it was a distinct genus. Morphological and behavioral characteristics prompted the American ornithologist Harold Douglas Pratt, Jr. in 1987 to propose that the species belonged to the spectacled birds. Follow-up studies have confirmed this view. The golden-eyed bird is probably closest related to the Micronesian species of the genus Rukia , i.e. the long-billed spectacle bird and the truk-eyed bird , or the monotypical Bonin- eyed bird ( Apalopteron ), which was once classified as a honey eater and is now considered a spectacle bird. The golden spectacle bird has an elongated tenth hand wing , while this is receded or absent in other representatives of the spectacle birds. This has led to the alternative assessment that the species is a basal representative of the spectacled bird.

etymology

The generic name, Cleptornis , is made up of the ancient Greek terms kleptes (robber or thief) and ornis (bird). However, this does not refer to the behavior of the bird, but to the old French name for the Mariana Islands les Îles des Voleurs , or "Islands of Thieves". The species-specific epithet marchei honors the French explorer and writer Antoine-Alfred Marche , who procured the type specimen.

distribution and habitat

The golden-rimmed bird is found on Saipan and Aguijan of the Northern Mariana Islands .

The golden-eyed bird is endemic to the Northern Mariana Islands in the western Pacific , where it is currently found on the islands of Saipan and Aguijan . Within its range, the golden-rimmed bird inhabits a number of different habitats in both natural and cultural landscapes . The species is common in natural forests, especially in secondary limestone forests . The golden-rimmed bird can also be found in open scrubland and suburban areas. On Saipan, the species is only missing in the marshes around Lake Susupe and in grass savannas .

features

The golden spectacle bird differs from other members of the spectacle bird family by the large eyes and the elongated outer hand-wing, which has receded in other species. It is a large representative of the spectacle birds, which can reach a length of 14 cm and a weight of about 20 grams. The species has a bright, showy plumage . The head plumage is colored orange-yellow with a white eye ring. The back plumage, the wings and the tail feathers, however, have a yellowish-green color, while the belly side is orange-gold. The bill and legs are also colored orange. There is only a slight sexual dimorphism in the color of the plumage between the sexes . The main difference between the males and the females is that they have longer wings, so that identification is usually only possible in the hand. The young birds have a similar plumage to the adult birds, but it is somewhat more blunt and mixed with brown spots on the face and neck and brown-yellow stripes on the breast plumage. The beaks and legs are also a little darker than that of the adult birds.

The voice of the golden-rimmed bird comprises a series of sounds. The singing is reminiscent of a scratchy trill. During the flight and in flocks, the species also makes short rasping calls and whistling tones. Chicks make a plaintive cry when begging for food.

behavior

Like other spectacle birds, the golden spectacle bird is also diurnal . In contrast to the bridle-eyed bird , which is not territorial and searches for food in groups, the golden-eyed bird can be observed in pairs or small family groups consisting of a breeding pair with young birds that have already fledged. The species is territorial, so that the pairs sing throughout the day to delimit their territory from neighboring pairs. Groups behave aggressively when they meet one another. Golden glasses birds are also aggressive towards the smaller rein glasses birds. The smaller birds are chased away by food and seats. Gold-eyed birds also fly through flocks of rein-eyed birds to disperse them. Although other species of passerine birds are attacked, it is less aggressive. In fact, the fox tail seeks the proximity of the golden-rimmed bird to look for food behind it and to pick up insects that have been scared off by the golden-rimmed birds .

While the golden-eyed bird is socially dominant compared to the rein-eyed bird and the fox fan tail, it is in turn chased away from the food sources by the Micronesia honey eater. Occasionally the species is driven away by fan tails if it comes too close to their nests.

Food and subsistence

Golden glasses bird on banana tree

The gold-rimmed bird is a generalist who feeds primarily on insects, fruits and berries. The birds prefer to look for food in pairs or in small family groups. Nectar is an important part of the menu. Together with the micronesia honey eater and the bridle-eyed bird, the golden-eyed bird functions as a pollinator of some tree species, but is not as important in this function as the other two species. The insects are either picked up from the bark of trees or leaves or caught in flight. Some tree species are preferred: The common forest tree Cynometra ramifolia is the most popular of the species and is visited more frequently than the equally common Guamia mariannae .

There is considerable overlap between the feeding area of ​​the golden-eyed bird and the bridle-eyed bird, but the golden-eyed bird is less specialized. A niche in the forests can be observed to a certain extent . While the bridle-eyed bird like the micronesia honey eater primarily searches for food in the canopy of the canopy , the golden-eyed bird finds its food both in the crown area and in the undergrowth of the forest as well as in smaller trees and bushes. The species shares this area with the fox tail, which, however, differs in the way it searches for food. This niche in the microhabitats also continues on a smaller scale . While the golden-rimmed bird also looks for insects in dead leaves and branches, the bridle-eyed bird prefers to pick them up from living leaves. Gold-rimmed birds are the most pronounced generalists of all songbird species in Saipan's forests. The versatility in terms of food and acquisition has been believed to be an adaptation to the challenges posed by the typhoons common in the Pacific , which can dramatically alter the structure of forests.

Breeding behavior

The breeding takes place on Saipan, where the nesting behavior of the species has been studied, over the whole year. The main breeding season seems to be between March and July. The gold-rimmed bird is monogamous . The nest is like a simple, unadorned cup made of needles from casuarines , grass and creepers. The nests are located at an average height of 2.9 m (between 1.5 and 6.5 m) above the ground in various tree species, u. a. Casuarina, Guamia , Cynometra , Leucaena or citrus plants . The nest robbers include the Karolinenstar and the Halsbandliest . The introduced emerald skink ( Lamprolepis smaragdina ) represents an additional threat .

A typical clutch comprises two eggs approximately 20.3 × 15.1 mm. The eggs are pale bluish-green in color with red or brown blobs on the wider end. Both parent birds incubate the eggs. They alternate about every 25 minutes. This species is extremely territorial in the immediate vicinity of the nest and also chases away other species such as the bridle-eyed bird, the fox tail and other golden-eyed birds. After being laid, the eggs are incubated for about two weeks until the chicks hatch. These are nests and are fed by both parent birds. The adult birds also clean the nest of feces. The diet of young birds consists almost exclusively of insects and caterpillars . The young birds fledge approximately two weeks after hatching . Afterwards they stay for some time with the parent birds in small groups.

Hazard and protection

Breeding in captivity is designed to ensure the species' survival

The range of the golden-rimmed bird has shrunk considerably since the arrival of humans on the Mariana Islands. Fossil bones of the species have been found on the nearby islands of Tinian and Rota . It is possible that the species was once native to Guam and other Mariana Islands.

At present, the gold-rimmed bird is still common. In fact, a 1996 study found that Saipan is one of the highest documented densities of any bird, with up to 2095 birds per square kilometer. It is believed that Saipan has reached its population limit and the island cannot feed more birds than it currently does. However, a 2009 study that also took into account the results of a 2007 study concluded that the population declined between 1982 and 2007. This also affected two other species on Saipan, the fox tail and the reed warbler . All three species are insectivorous and affected by habitat loss. Nevertheless, the golden-rimmed bird is still relatively common and the current total population is estimated at around 71,997 birds.

The IUCN classifies the species as critically endangered because it is expected that the population will experience a rapid decline. The greatest threat comes from the night tree snake , which was originally widespread in Australia , New Guinea and the Solomon Islands and has already eradicated all twelve terrestrial bird species on the nearby island of Guam after its erroneous introduction. The snake recently reached Saipan, one of the islands within the range of the golden-rimmed bird with the largest population of the species. The isolation of Aguijan makes the introduction of the brown night tree snake unlikely, but the only 718 hectare island is home to only a small population that is susceptible to Natural disasters such as the typhoons that are common in the region .

Efforts are already being made to breed the species in captivity and to contain the spread of snakes on Saipan. Six zoos have received the species recently and breeding should begin in 2011. However, the North Carolina Zoo had its first successes in breeding in 2009. Offspring birds are introduced to new islands. In addition, 50 birds are to be relocated from Saipan to Sarigan , an island that is free from predators , to ensure the conservation of the species.

Web links

Commons : Cleptornis marchei  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e f Bas van Balen: Family Zosteropidae (White-eyes) . In: Josep del Hoyo, Andrew Elliott, David Christie (Eds.): Handbook of the Birds of the World . Volume 13, Penduline-Tits to Shrikes . Lynx Edicions, Barcelona 2008, ISBN 978-84-96553-45-3 , p. 480.
  2. ↑ Oustalet, E. (1889). Note on the faune ornithologique des Res Mariannes. Le Naturaliste 3 (64): 260.
  3. ↑ a b c d Cleptornis marchei in the Red List of Threatened Species of the IUCN 2013.2. Listed by: BirdLife International, 2012. Retrieved December 1, 2013.
  4. ↑ a b c d e f Rare Birds Yearbook 2009 . MagDig Media Limited, England 2008, ISBN 0955260752 , pp. 194-95.
  5. ^ H. Douglas Pratt, Bruner, Phillip & Berrett, Delwyn: The Birds of Hawaii and the Tropical Pacific . Princeton University Press , Princeton 1987, ISBN 0-691-08402-5 , pp. 286-87.
  6. ↑ a b Beth Slikas, Jones, Isaac B .; Derrickson, Scott R. & Robert C. Fleischer: Phylogenetic relationships of Micronesian white-eyes based on mitochondrial sequence data . In: Auk . 117, No. 2, 2000, pp. 355-365. doi : 10.1642 / 0004-8038 (2000) 117 [0355: PROMWE] 2.0.CO; 2 .
  7. ↑ James A. Jobling: A Dictionary of Scientific Bird Names . Oxford University Press , Oxford 1991, ISBN 0-19-854634-3 , pp. 56 & 140.
  8. ^ Rollin H. Baker: The avifauna of Micronesia, its origin, evolution and distribution . In: University of Kansas Publications, Museum of Natural History . 3, No. 1, 1951, p. 303. Retrieved January 20, 2009.
  9. ↑ a b c d Robert Craig: Foraging behavior and microhabitat use of two species of white-eyes (Zosteropidae) on Saipan, Micronesia . (PDF) In: Auk . 107, No. 3, 1990, pp. 500-505. Retrieved January 20, 2009.
  10. ^ A b Robert Craig: Seasonal population surveys and natural history of a Micronesian bird community . (PDF) In: Wilson Bulletin . 108, No. 2, 1996, pp. 246-267.
  11. ↑ Hanne Mortensen, Dupont, Yoko Luise & Jens M. Olesen: A snake in paradise: Disturbance of plant reproduction following extirpation of bird flower visitors on Guam . In: Biological Conservation . 141, No. 8, 2008, pp. 2146-2154. doi : 10.1016 / j.biocon.2008.06.014 .
  12. ^ A b Robert J. Craig, Beal, Kathleen G .: Microhabitat partitioning among small passerines in a Pacific island bird community . In: Wilson Bulletin . 113, No. 3, 2001, pp. 317-326. doi : 10.1676 / 0043-5643 (2001) 113 [0317: MPASPI] 2.0.CO; 2 .
  13. ^ A b c d Colleen Stinson, Derek Stinson: Nest sites, clutch size and incubation behavior in the Golden White-Eye . (PDF) In: Journal of Field Ornithology . 65, No. 1, 1994, pp. 65-69. Retrieved January 20, 2009.
  14. ↑ Sachtleben, Thalia: Predation and nest success of forest birds in native and nonnative habitat on Saipan, Mariana Islands ( Memento of the original from July 22, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF) (MSc thesis). Colorado State University 2005, pp. 1-95. @1@ 2Template: Webachiv / IABot / www.colostate.edu
  15. ^ David Steadman : Extinction and Biogeography in Tropical Pacific Birds . University of Chicago Press, Chicago 2006, ISBN 978-0-226-77142-7 , p. 377.
  16. ^ Hirschfeld, Erik (editor): Rare Birds Yearbook 2008 . MagDig Media Limited, England 2007, ISBN 978-0-9552607-3-5 , p. 218.
  17. ^ Richard J. Camp, Pratt, Thane K .; Marshall, Anne P .; Amidon, Fred & Laura L. Williams: Recent status and trends of the land bird avifauna on Saipan, Mariana Islands, with emphasis on the endangered Nightingale Reed-warbler Acrocephalus luscinia . In: Bird Conservation International . 19, No. 4, 2009, pp. 323-337. doi : 10.1017 / S0959270909008417 .
  18. ^ Julie Savidge: Extinction of an island forest avifauna by an introduced snake . In: Ecological Society of America (Ed.): Ecology . 68, No. 3, 1987, pp. 660-668. JSTOR 1938471 . doi : 10.2307 / 1938471 .
  19. ^ Robert Craig: Conservation of endangered white-eyes (Zosteropidae) in the tropical Pacific . In: 22nd International Ornithological Conference (PDF), Bird Conservation Research, Inc, Putnam, CT, and Durban, South Africa 1998, pp. 1–8. Archived from the original on March 4, 2016 Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (Accessed November 14, 2008). @1@ 2Template: Webachiv / IABot / www.birdconservationresearch.org
  20. ↑ Jeffrey Bonner: Reptilian invasion: Saving Pacific island birds from snakes . In: St. Louis Post-Dispatch . Archived from the original on September 17, 2008 Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . Retrieved November 14, 2008. @1@ 2Template: Webachiv / IABot / www.stltoday.com 
  21. ↑ BirdLife International : BirdLife Species Factsheet: Golden White-eye . 2008. Retrieved January 15, 2009.
  22. ↑ Debbie Zombeck: A Feather in Our Cap Archived from the original on December 3, 2013. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF) In: Alive: Magazine of the North Carolina Zoological Society . 63, Winter 2011, p. 5. Retrieved November 25, 2012. @1@ 2Template: Webachiv / IABot / www.nczoo.com
  23. ^ Memphis Zoo: The Conservation Action Network (CAN) . 2009. Archived from the original on January 25, 2010. Info: The archive link was automatically inserted and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved December 11, 2009. @1@ 2Template: Webachiv / IABot / www.memphiszoo.org