Barking owl


The barking owl or barking boobook, also known as the winking owl, is a nocturnal bird species native to mainland Australia and parts of New Guinea and the Moluccas. They are a medium-sized brown owl and have a characteristic voice with calls ranging from a barking dog noise to an intense human-like howl.

Etymology

The owl takes its name from its characteristic barking voice. For a short period before 2016, the Red List of Threatened Species referred to this species as the "barking boobook". However, this is not used as a common name in Australia or other English speaking areas in this species' range and has now been corrected to barking owl. The Yanyuwa name for the owl is mulurrku.

Taxonomy

The barking owl was first described by the English ornithologist John Latham in 1801 with the binomial name Falco connivens. Latham commented that the species "Inhabits New Holland, but no history annexed, further than that it has a wonderful faculty of contracting and dilating the iris: and that the native name is Goora-a-Gang." The specific epithet is the Latin connivens 'winking'.
There are five subspecies:
  • N. c. rufostrigata - north Maluku Islands
  • N. b. remigialis Stresemann, 1930 - Kai Islands. Stresemann described it in 1930 from a specimen collected in 1909. Poorly known, it has been recorded twice more in 1998 and 2010.
  • N. c. assimilis Salvadori & D'Albertis, 1875 - east New Guinea, Manam, Karkar and Daru Islands
  • N. c. peninsularis Salvadori, 1876 - north Australia
  • N. c. connivens - southwest, east and southeast Australia
N. b. remigialis was formerly considered a subspecies of the Australian boobook but was transferred to N. connivens by the International Ornithological Congress in 2022.

Description

The barking owl is coloured brown with white spots on its wings and a vertically streaked chest. They have large eyes that have a yellow iris, a discrete facial mask and yellow skin on the feet. Their underparts are brownish-grey and coarsely spotted white with their tail and flight feathers being strongly banded brown and white. They are a robust, medium-sized owl long and their wingspan is between. They weigh between . Size varies only slightly between the male and female birds with the male barking owl being 8-10 % heavier. They are one of only a handful of owl species exhibiting normal sexual dimorphism. In a banding study conducted in the Pilliga forests of northern New South Wales, males averaged with females averaging . In Australia, the smallest barking owls are found on Cape York Peninsula and the largest in southern Australia.

Distribution and habitat

The barking owl lives in mainland Australia along the eastern and northern coast of the continent and the southwest areas surrounding Perth, Western Australia. Inland they occupy areas near lakes and waterways or other wooded environments. They also live in drier parts of New Guinea and the Moluccas. Once widespread, barking owls are now less common in southern mainland Australia.
They choose to live in forests or woodland areas that have large trees for nesting and foliage cover for roosting. They often reside near river, swamp or creek beds as these features often have large trees with hollows required for nesting and the productivity to support sufficient prey.
The only detailed studies of barking owl home-ranges have been conducted in southern Australia where the species is declining. In northern Victoria, barking owl pairs were found to average a home-range of with little overlap between pairs. Foraging was concentrated within forested areas of each home range. These results are mirrored in the Pilliga forests of northern NSW although there the home ranges were larger, often up to.
Although barking owls are uncommon and sometimes even rare in many suburban areas, they occasionally do get accustomed to humans and even start to nest in streets or near farm-houses.
The species is absent from most of Sydney besides scattered pockets of woodland located on the northern beaches, and to the north and southwest of the region.

Behaviour

Diet

The barking owl has one of the broadest diets of any Australian owl. Barking owls hunt in timbered and open habitats but usually rely on trees as hunting perches. Their diet includes prey taken from the ground, the trees, the surface of waterbodies, and directly from the air. In some locations mammals make up the majority of prey biomass with prey sizes from mice and small carnivorous marsupials up to rabbits and brushtail possums around a kilogram or more in weight. Sugar gliders are a frequent prey item. Bats of all sizes are also commonly taken.
In some areas, bird prey items make a sizeable contribution to the diet. Birds up to the size of sulphur-crested cockatoos and ducks are taken, but many smaller birds are more commonly taken. One frequent prey item is the tawny frogmouth, a nocturnal bird of Australian forests and woodlands. Insect prey items can dominate the prey item count. Beetles and moths are commonly taken on the wing. A range of other insects are also consumed. Occasionally frogs, reptiles, fish or crustaceans are eaten. In summary, if an animal can be detected by a barking owl and it is of its size or smaller, it can be considered as potential prey.

Breeding

The breeding season of the barking owl is from July to September in the north of Australia and from August to October in the south. The nest is formed of decayed debris, usually in the large hollow of an old eucalypt near a river. A clutch of 2 or 3 roundish, dull-white eggs, each measuring, is laid and incubated by the female for about 36 days. The young at first are covered in white down and fledge by 5 to 6 weeks.

Voice

Most people hear the barking owl rather than see it as it has a loud and explosive voice. The main territorial vocalisation is in the form of a double 'hoot', similar in pattern to the other Australian hawk owls. It sounds like a double dog bark, so closely resembling a small dog that it is difficult to tell the difference. The barking owl name is derived from these calls. Males 'bark' at a lower pitch than females, particularly when a pair perform the barking calls together. Barking calls can be varied in pitch and intensity depending on the purpose of the call. Loud barks are given as territorial calls and can be used in confrontations between pairs in adjacent territories. Lower pitched softer barks are often used around the nest or roost areas by the male to call the female for a meal.
Barking owls also have a range of other vocalisations. These might be described as growls, howls or screams and bleating and twittering. Growls and howls are part of a continuum of calls relating to threats, particularly during nesting. The level of the threat, typically determines the level of the call, with the lowest level being a low pitched and soft growl. This is usually a warning note to the nesting partner. This climbs into a louder and higher pitched series of howls, often made while the owl dives at the intruder. At its most extreme, this might be described as a scream.
The screaming of the barking owl is said to sound like a woman or child screaming in pain. Hearings of 'screaming lady,' as it is so nicknamed, are rare and many only hear the sound once in their life even if they live next to a barking owl nest. While screams are usually related to nest defence, some barking owls will make this call in non-nest related situations. Myths surround the events that caused the owl to originally "mimic" the sounds.
Juvenile barking owls have a twittering, insect-like call when begging for food. It is similar to that of other juvenile hawk owls. Female barking owls will often make a gentle bleating sound when receiving food from the male owl. An excited variation of this sound is made during copulation.

Conservation status

Barking owls are not listed as threatened on the Australian Environment Protection and Biodiversity Conservation Act 1999. However, their conservation status varies from state to state within Australia. For example:
In the State of Victoria, according to Action Statement 116 issued under the FFG Act: "The Barking Owl is the most threatened owl in Victoria. The population has been estimated to be fewer than 50 breeding pairs, though work in north-eastern Victoria suggests that this estimate may have been conservative in the late 1990s and early 2000s. Existing records of Barking Owls on the Atlas of Victorian Wildlife database are unlikely to give an accurate representation of the current distribution and abundance of the species. Many of these records are dated, occurring in areas where once-suitable habitat has been lost or degraded. Extensive surveys in Victorian forests have shown the species to be rare, localised and mainly found in north-eastern Victoria."
A similar pattern of decline is evident in NSW with surveys in 1998, 2004 and 2008 showing barking owls to be rare in areas that had been assumed to be strongholds. Larger population areas have been demonstrated to be isolated from one another.
In south-western Australia a survey of 100 forest sites found no barking owls.
In contrast, barking owl calls are still a common sound in many wooded parts of Queensland and the Northern Territory, although there have been few recent published population studies/surveys in those areas.