Hawaiian sickle bird

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Hawaiian sickle bird
Akiapolaau.jpg

Hawaiian sickle-bird ( Hemignathus munroi )

Systematics
Subordination : Songbirds (passeri)
Family : Finches (Fringillidae)
Subfamily : Goldfinches (Carduelinae)
Tribe : Clothes birds (Drepanidini)
Genre : Hemignathus
Type : Hawaiian sickle bird
Scientific name
Hemignathus munroi
Pratt , 1979

The Hawaiian sickle-clad bird ( Hemignathus munroi ), called ʻAkiapolaʻau in Hawaiian , is a songbird species from the tribe of honeysuckle birds . He is on the main island of Hawai'i in the Hawaiian Islands endemic . The species epithet honors the American botanist and ornithologist George Campbell Munro .

features

The Hawaiian sickle bird is a medium-sized bird that reaches a size of 14 cm. Males reach a weight of 19.8 to 37 g, females are slightly lighter at 17 to 35 g. The long upper beak is curved downwards. The straight lower bill is about half as long as the upper bill and has a thin chisel point. When the beak is closed, there is usually a small gap between the halves of the beak. In the male, the facial color , including the stripe above the eyes , is light golden yellow. This golden yellow color also extends over the throat and the underside and merges into the whitish at the under tail-coverts . The entire upper side as well as the upper and rear edges of the ear patches are darker gold-olive, whereby the coloration is not sharply demarcated from the yellowish areas. The reins are black. The arm and hand wings are dark sepia brown with golden olive edges. The iris is dark brown, the beak and legs are black. The female is more dull in color than the male. The top is grayer and the bottom is lighter. The yellowing of the breast is not as far back as in the male. The sides of the face are colored darker. The over-eye stripe is unclear. The females also have smaller beaks than the males. The youth dress is yellowish gray on the back and yellowish brown on the rump . The tips of the wing covers (indistinct wing bands) are light yellow to off-white. The underside is light olive gray. The flanks are tinted yellow-brown and the chest is mottled with indistinct dark feather tips. The beak is dull straw yellow. In the immature birds there is no breast markings. In the second year the wing bands disappear and the young bird resembles the female, but the color on the throat and chest is less yellowish. The plumage of the adult birds is only reached in the third year.

Vocalizations

The calls include a two-tone to four-tone whistle that sounds like "cheerdle-ee", a two-tone ascending whistle that consists of "teerwee" or "chew-weee" tones as well as a monotonous ascending "squeet" or a soft " swit ". The courtship song consists of a lively, rapid warble and usually ends in a pair of ascending and descending notes that sound like "tu-tu-whéé-wheer-tu-du-whéé-you." Whispering (or lower singing) is a quieter version of courtship singing with additional trills and trills. The signal or contact call of the juvenile and immature birds consists of a conspicuous “tseoop” or “cheerp”.

habitat

The Hawaiian sickle bird lives in semi-arid and humid forests, which mainly consist of the ironwood Metrosideros polymorpha (ʻŌhiʻa) and koa acacias ( Acacia koa ) as well as ʻŌhiʻa rainforests ( Metrosideros polymorpha ). Until recently it was also found in dry Mamane-Naio forests from Sophora chrysophylla and Myoporum sandwicense , in the past it was found in all Hawaiian forest types. He prefers the koa acacia forests, including the secondary forest plantations , and altitudes between 1340 and 2700 m.

Way of life

Reproductive behavior

The Hawaiian sickle bird is a resident bird that breeds year-round, with the main breeding season being between February and July. The monogamous partners stay together in stable populations for several breeding seasons and defend a large area throughout the year. The nest is mostly built by the female, with little help from the male. It consists of strips of bark from Metrosideros polymorpha and from pieces of Cibotium -Baumfarnen. The 2 cm wide bark strips protrude 5 cm from the top of the nest and give the nest the appearance of a miniature fence. The nest has an outer circumference of 11 × 14 cm, a height of 15 cm, an inner bowl diameter of 6.5 to 7.9 cm and a bowl depth of 4.5 cm. It is usually located at a height of 7 to 22 m in a terminal cluster of leaves of an ʻŌhiʻa tree, more rarely in a tree hollow. The clutch size is usually very small with one egg per clutch, rarely two eggs are laid. The eggs of the species measure 22.7 × 17 mm and have a light cream color with brownish-red speckles mostly at the longer end. There is no information about the incubation period. The chicks are hatched by the female, with one chick leaving the nest after 21 days in one case. The dependency of the young birds on the parents is unusually long and is four to thirteen months, whereby the adult birds can feed young birds from two broods at the same time.

Eating behavior

The diet includes spiders, beetle larvae and adult beetles, lacewing larvae and butterfly caterpillars, especially those that are hidden in dead wood or behind the bark. Flower nectar and the sap of the ʻŌhiʻa tree enrich the food supply. The Hawaiian sickle bird foraging in trees such as Myrsine lessertiana , Sophora chrysophylla , Myoporum sandwicense , koa acacias and Metrosideros polymorpha , although the behavior between males and females can vary somewhat. While the males prefer the tree trunks and large branches when searching for food, the females are more likely to be observed on the small twigs and tufts of leaves. Lichen tufts are preferred by both sexes. The halves of the beak are used independently of each other. The Hawaiian Crescent Bird pecks with its lower bill while keeping its upper bill out of the way. He uses his upper beak to drill and poke, while he supports himself with his lower beak. He makes characteristic hammering movements. The'akiapola'au wins tree sap by the boring and the recurrence of a series of juice channels in a similar manner as the woodpecker of the genus Saftlecker ( Spyrapicus do). These so-called "Aki trees" are often defended. After the breeding season, family groups can be observed in mixed flocks of birds roaming around within the area.

status

The IUCN classifies the'akiapola'au as "high risk" ( endangered ). The species is present in the Hawai'i Endemic Bird Area and limited to a very small, highly fragmented distribution area of ​​150 km². Once widespread, the Hawaiian sickle-winged bird is now only found at higher altitudes on the slopes of the Mauna Kea and Mauna Loa volcanoes . The main population is in the Hamakua District (in the center of the Hakalau Forest National Wildlife Refuge), in the Keauhou-Kulani region (in the northeast of Hawaii Volcanoes National Park ), in the Kau District in the Kau Forest Reserve and in the Kapapala Forest Reserve and in the area of Kahuku can be found within the Hawaii Volcanoes National Park. Overall, there has been a shrinking of the range and a decline in the population, although it is growing locally. The population estimates fluctuate to a large extent, apparently because of the different survey techniques. BirdLife International currently assumes a population of 800 adult birds and a rounded total of 1200 individuals. Small relic populations in the Kona and Mamane Naio Forests on the windward slopes of Mauna Kea have disappeared since 2002. Three remaining populations are isolated in an unfavorable habitat. The restriction to the higher altitudes is undoubtedly the result of the spread of mosquitoes (Culicidae) and the diseases that they have transmitted in the lower altitudes. The highland population is currently endangered by rats and feral cats. In addition, the habitat is being destroyed by feral grazing cattle and introduced European mouflons ( Ovis musimon ). The regeneration of the koa acacia forests after the removal of the grazing animals has resulted in the recovery of the Hawaiian sickle-winged bird in certain locations, which is a success of ungulate control. Most of the remaining population occurs in sanctuaries created for forest birds, particularly the Hakalau Forest National Wildlife Refuge and the Three Mountain Alliance. The Puʻu Waʻa Waʻa Forest Bird Sanctuary on the Hualālai volcano was fenced off as a possible reintroduction site.

Systematics

The Hawaiian sickle bird was first described in 1893 by Walter Rothschild under the name Heterorhynchus wilsoni . In 1950 he was placed in the genus Hemignathus by Dean Amadon . However, since the species epithet wilsoni had previously been assigned to the Hawaiian Amakihi bird ( Hemignathus virens , synonyms: Chlorodrepanis wilsoni , Himatione wilsoni ) and Rothschild’s name was therefore invalid, Harold Douglas Pratt used the currently valid name combination Hemignathus munroi from 1979 .

literature

  • Pratt, Harold Douglas: The Hawaiian Honeycreepers . Oxford University Press, 2005, ISBN 978-0-19-854653-5 .: P. 254-255
  • Pratt, Harold Douglas: Drepanididae (Hawaiian Honeycreepers) In: Del Hoyo, J .; Elliot, A. & Christie D. (Editors). (2010). Handbook of the Birds of the World. Volume 15: Weavers to New World Warblers. Lynx Edicions, ISBN 978-84-96553-68-2 : p. 657

Individual evidence

  1. ↑ Pyle, RL, & P. ​​Pyle. 2009. The Birds of the Hawaiian Islands: Occurrence, History, Distribution, & Status (PDF; 49 kB) . BP Bishop Museum, Honolulu, HI, USA Version 1 (December 31, 2009)
  2. ^ Pratt, Harold Douglas: The Hawaiian Honeycreepers . Oxford University Press, 2005, ISBN 978-0-19-854653-5 .: P. 254-255
  3. ↑ Pratt, HD 1979: Nomenclatural notes on Hawaiian birds . In: 'Elepaio 39: pp 84-85
  4. ^ IOC World Bird List 3.2

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