Boobookkauz

Bestimmung

The smallest owl on the Australian mainland, the Australian boobook is 27 to 36 cm (10.5 to 14 in) long. The nominate subspecies is the largest. It has short, rounded wings and a short tail, with a compact silhouette in flight. Australian boobooks on the Australian mainland follow Bergmann's rule, in that birds from cooler and more southerly parts of the range tend to be larger. Thus, birds from the Canberra region weigh around 300 g (11 oz) while those from the Cape York Peninsula and Broome are around 200 g (7.1 oz). Females tend to be a little larger and heavier than males, with males weighing 146–360 g (5.1–12.7 oz) and females 170–298 g (6.0–10.5 oz).<p>The Australian boobook has generally dark brown head and upperparts, with white markings on the scapulars and spots on the wings. Its head lacks tufts common in other owls and has a paler facial disk, with a white supercilium (eyebrow) and dark brown ear coverts and cheeks. The brown feathers of the upper forehead, above the supercilium, and sides of the neck have yellow-brown highlights. The feathers of the lores, chin and throat are white with black shafts. The feathers of the underparts are mostly brown with white spots and dark blue-grey bases. The upper tail is dark brown with lighter brown bars and a grey fringe at the end, while the undertail is a lighter grey-brown. The female tends to be more prominently streaked than the male overall, though this is inconsistent and wide variation is seen. The eyes have been described as grey-green, green-yellow, or even light hazel. The bill is black with a pale blue-grey base and cere. The feet are greyish to pinkish brown with dark grey to blackish claws. The underparts are pale, ranging from buff to cream, and are streaked with brown. The overall colour is variable and does not appear to correspond to subspecies or region. In northern and central Australia, Mayr found that the colour of the plumage appears to correlate with the rainfall or humidity, paler birds being found in three disjunct areas, each around 1,600 km (990 mi) away from the other two: the western Kimberley and Pilbara, Sedan on the Cloncurry River, and around Ooldea, with darker birds found on Cape York and Melville Island.<p>Young Australian boobooks are usually paler than adults and do not attain adult plumage properly until their third or fourth year. Juveniles (up to a year old) have whitish underparts and foreneck, a larger and more prominent pale eyebrow and larger whitish spots on their upperparts. The tips of their feathers are white and fluffy, remnants of the nestlings' down. These are worn away over time, persisting longest on the head. The feathers of the head, neck and underparts are fluffier overall. Immatures in their second and third year have plumage more like adults, though their crowns are paler and more heavily streaked.<p>On mainland Australia, it could be confused with the barking owl or the brown boobook (Ninox scutulata), a rare vagrant to the northwest, although the Australian boobook is easily distinguished by its squat posture and distinctive pale border to its face mask. The Tasmanian boobook has been recorded from southern Victoria, with one record from New South Wales. It has darker and more reddish upperparts with brighter white dots, with more prominent white dots and a yellow-brown tinge to the underparts. It has pinkish grey feet and golden eyes.

Taxonomie

English ornithologist John Latham described the boobook owl as Strix boobook in 1801, writing about it in English, before giving it its scientific name, taking its species epithet from a local Dharug word for the bird. The species description was based on a painting by Thomas Watling of a bird—the holotype—in the Sydney district in the 1790s. John Gould described Athene marmorata in 1846 from a specimen in South Australia. This is regarded as a synonym. German naturalist Johann Jakob Kaup classified the two taxa into subgenus Spiloglaux of a new genus Ieraglaux in 1852, renaming S. boobook to Ieraglaux (Spiloglaux) bubuk. In his 1865 Handbook to the Birds of Australia, Gould recognised three species, all of which he placed in the genus Spiloglaux: S. marmoratus from South Australia, S. boobook, which is widespread across the Australian mainland and Tasmania, and S. maculatus from southeastern Australia and Tasmania. Meanwhile, in India, English naturalist Brian Houghton Hodgson had established the genus Ninox in 1837, and his countryman Edward Blyth placed the Australian boobook in the new genus in 1849.<p>Australian boobook has been designated the official name by the International Ornithological Committee, changed from "southern boobook" in 2019 with the separation of some Indonesian subspecies. The common name comes from the two-tone call of the bird, and has also been transcribed as "mopoke". William Dawes recorded the name bōkbōk "an owl" in 1790 or 1791, in his transcription of the Dharug language, and English explorer George Caley had recorded the native name as buck-buck during the earliest days of the colony, reporting that early settlers had called it cuckoo owl as its call was reminiscent of the common cuckoo. He added, "The settlers in New South Wales are led away by the idea that everything is the reverse in that country to what it is in England; and the Cuckoo, as they call this bird, singing by night, is one of the instances they point out." Gould recorded local aboriginal names: Goor-goor-da (Western Australia), Mel-in-de-ye (Port Essington), and Koor-koo (South Australia). Alternative common names include spotted owl and brown owl. The Ngarluma people of the western Pilbara knew it as gurrgumarlu. In the Yuwaaliyaay dialect of the Gamilaraay language of southeastern Australia, the Australian boobook is guurrguurr.<p>Dutch naturalist Gerlof Mees and German evolutionary biologist Ernst Mayr regarded the taxonomy of the boobook owl complex as extremely challenging, the latter remarking in 1943 that it was "one of the most difficult problems I have ever encountered". In his 1964 review of Australian owls, Mees treated Australian and New Zealand boobooks, along with several taxa from Indonesia and Papua New Guinea, as one species—Ninox novaeseelandiae—with 16 subspecies. In his 1968 book Nightwatchmen of the Bush and Plain, Australian naturalist David Fleay observed that the boobooks from Tasmania more closely resembled those of New Zealand than those from mainland Australia, though he followed Mees in treating them as a single species. The Australian boobook was split from the Tasmanian boobook and morepork in volume 5 of the Handbook of the Birds of the World in 1999, though several authors, including Australian ornithologists Les Christidis and Walter Boles, continued to treat the three taxa (Australian plus Tasmanian boobooks and moreporks) as a single species.<p>Examining both morphological and genetic (cytochrome b) characters in 2008, German biologist Michael Wink and colleagues concluded that the Australian boobook is distinct from the morepork and Tasmanian boobook (which they proposed to be raised to species status as Ninox leucopsis), and that it is instead the sister taxon to the barking owl (N. connivens). A 2017 study by Singapore-based biologist Chyi Yin Gwee and colleagues analysing both multi-locus DNA and boobook calls confirmed a sister relationship of N. n. novaeseelandiae and N. (n.) leucopsis and their close relationship to N. connivens. Genetic and call analysis show the Christmas boobook (N. natalis) to be very close to the Australian populations of the Australian boobook, leading Gwee and colleagues to suggest it be reclassified within this species.<p>Gwee and colleagues found that boobook populations on larger, mountainous islands were more distinct from Australian stock, while those on flatter smaller islands were much more similar. This was taken as suggesting that these locations were colonised much more recently, after previous populations had become extinct.<p>Seven subspecies of Ninox boobook are recognised in version 12.1 of the IOC World Bird List, published in January 2022:<p>Three former subspecies of Ninox boobook have been classified as distinct species since 2017: namely, Rote boobook (Ninox rotiensis), Timor boobook (N. fusca), and Alor boobook (N. plesseni). The subspecies N. b. remigialis was transferred to the barking owl by the International Ornithological Congress in 2022.

Wissenschaftlicher Name

Ninox boobook

Autorität

(Latham, 1801)

Ordnung

Strigiformes

Familie

Strigidae

Gattung

Ninox

Verbreitung und Lebensraum

The Australian boobook is found across mainland Australia, although it is scarce in more arid regions such as western New South Wales, southwestern and western Queensland, much of South Australia away from the coast and interior Western Australia and Northern Territory. In drier areas, it is generally found along watercourses such as the Darling and Paroo Rivers, and Lake Eyre Basin. It is found on numerous offshore islands such as Groote Eylandt, Melville Island, Mornington Island in the Gulf of Carpentaria and many islands off eastern Australia. It is found in southern New Guinea, Timor and surrounding islands in Indonesia. It is found in a wide range of habitats, from forest and open woodland to scrubland and semidesert areas. In Australia, it resides in mainly eucalypt forests. It has adapted to landscapes altered by human activity and is found in farmland and suburban areas as long as some scattered trees are present.

Zugverhalten

Standvogel

Verhalten

Zugverhalten: Standvogel.

Schutzstatus

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Bestandstrend

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