Tasmanian Masked Owl
Encyclopedia
The Tasmanian Masked Owl (Tyto novaehollandiae castanops) is a bird in the barn-owl family
Tytonidae
that is endemic to the island state of Tasmania
, Australia
. It is the largest subspecies
of the Australian Masked Owl, the largest Tyto owl in the world, and is sometimes considered a full species. The subspecific name castanops, meaning “chestnut-faced”, comes from the colouring of the facial disc. It was first described by John Gould (as Strix castanops), who wrote about it in his “Handbook to the Birds of Australia” as
. The owls inhabit both wet and dry eucalypt
forest
s, woodland
s and adjoining areas of agricultural land. Preferred habitat is areas close to the forest edge, containing a mosaic of understorey components. They require large old-growth trees with capacious hollows for nesting. The home range of a breeding pair may be more than 10 km² (3.9 sq mi); areas identified as important for breeding include the east coast between Hobart
and St Marys
, the Derwent and Huon Valleys and the mid-north coast, as well as fragmented patches in the Tamar Valley
and the north-east coast. It has been recorded from Maria
and Bruny Islands.
The owl has also been successfully introduced to Lord Howe Island
, a subtropical territory of New South Wales
in the Tasman Sea
between Australia and New Zealand
.
and monogamous pairs. They nest
in large tree hollow
s with a floor of decaying wood debris. The female is fed by the male while incubating
a clutch of 2-4 eggs
for about 42 days before hatching. The chicks are covered in, at first, white, then creamy down, and fledge
in 10–12 weeks. Fledged owls with traces of down
may remain in the vicinity of the nest for several weeks. Breeding is seasonal with most eggs laid in spring from late October to early November.
Anecdotally, Tasmanian Masked Owls were first bred in captivity
in 1945 in Launceston
by Miss Audrey Lee. However, the first detailed account of such an achievement is by David Fleay
, who bred them at the Healesville Sanctuary
in Victoria in 1946.
, bandicoot
s and brushtail possum
s. The main diet includes introduced rodent
s and rabbits in agricultural areas, and marsupials and native birds in less disturbed habitats. They often hunt from perches using sound to detect prey, which is usually taken on the ground by striking with the feet and using the talons to pierce and kill.
, because of its small population (estimated at about 1330 breeding birds, or 615 pairs) as well as ongoing habitat loss, especially of old-growth forest suitable for breeding. An important conservation need is to maintain nesting habitat in production forests. It is also threatened by competition for nest hollows by feral
bees
, kookaburras
and possums
.
s. The population there is considered to be a threat to the endemic Lord Howe Woodhen
and Lord Howe Currawong
, as well as to breeding seabird
s, and is culled when possible.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Tytonidae
Tytonidae
Barn-owls are one of the two families of owls, the other being the true owls, Strigidae. They are medium to large sized owls with large heads and characteristic heart-shaped faces. They have long, strong legs with powerful talons...
that is endemic to the island state of Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It is the largest subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the Australian Masked Owl, the largest Tyto owl in the world, and is sometimes considered a full species. The subspecific name castanops, meaning “chestnut-faced”, comes from the colouring of the facial disc. It was first described by John Gould (as Strix castanops), who wrote about it in his “Handbook to the Birds of Australia” as
”…a species distinguished from all the other members of its genus by its great size and powerful form. Probably few of the Raptorial birds, with the exception of the Eagles, are more formidable or more sanguinary in disposition."
"Forests of large but thinly scattered trees, skirting plains and open districts, constitute its natural habitat. Strictly nocturnal in its habits, as night approaches it sallies forth from the hollows of the large gum-trees, and flaps slowly and noiselessly over the plains and swamps in search of its prey, which consists of rats and small quadrupeds generally.”
Description
Tasmanian Masked Owls are not only large, but robust. They weigh up to 1.26 kilograms (2.8 lb) with a wingspan of up to 129 centimetres (50.8 in). Their plumage is mainly a variable combination of browns and greys, generally darker than the other Australian subspecies. Their upperparts are dark brown to pale chestnut, with white speckling. Females are considerably darker, as well as larger, than the males, ranging from 43 to 57 cm (16.9 to 22.4 in) in length, compared with the males’ 35 to 42 cm (13.8 to 16.5 in). They have broad, black-bordered, buff to chestnut facial discs, and fully feathered legs with powerful feet and long talons.Distribution and habitat
The natural range of the owl is limited to Tasmania, where it has been recorded throughout the state, with the exception of the south-westSouth West Tasmania
South West Tasmania is a region in Tasmania that has evolved over the fifty years between its consideration as a potential resource for development to its consideration as World Heritage wilderness...
. The owls inhabit both wet and dry eucalypt
Eucalypt
Eucalypts are woody plants belonging to three closely related genera:Eucalyptus, Corymbia and Angophora.In 1995 new evidence, largely genetic, indicated that some prominent Eucalyptus species were actually more closely related to Angophora than to the other eucalypts; they were split off into the...
forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
s, woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...
s and adjoining areas of agricultural land. Preferred habitat is areas close to the forest edge, containing a mosaic of understorey components. They require large old-growth trees with capacious hollows for nesting. The home range of a breeding pair may be more than 10 km² (3.9 sq mi); areas identified as important for breeding include the east coast between Hobart
Hobart
Hobart is the state capital and most populous city of the Australian island state of Tasmania. Founded in 1804 as a penal colony,Hobart is Australia's second oldest capital city after Sydney. In 2009, the city had a greater area population of approximately 212,019. A resident of Hobart is known as...
and St Marys
St Marys, Tasmania
St Marys is a small township nestled at the junction of the Tasman Highway and the Esk Highway on the East Coast of Tasmania, Australia just 10 kilometres from the coast....
, the Derwent and Huon Valleys and the mid-north coast, as well as fragmented patches in the Tamar Valley
Tamar Valley, Tasmania
The Tamar Valley is a picturesque valley in Tasmania. It runs north-west from the northern city of Launceston to the coast either side of the Tamar River, a distance of approximately 50 km....
and the north-east coast. It has been recorded from Maria
Maria Island
Maria Island is a mountainous island off the east coast of Tasmania. The entire island is a national park. Maria Island National Park has a total area of 115.50 km², which includes a marine area of 18.78 km² off the island's northwest coast. The island is about 20 km in length from...
and Bruny Islands.
The owl has also been successfully introduced to Lord Howe Island
Lord Howe Island
Lord Howe Island is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, directly east of mainland Port Macquarie, and about from Norfolk Island. The island is about 11 km long and between 2.8 km and 0.6 km wide with an area of...
, a subtropical territory of New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
in the Tasman Sea
Tasman Sea
The Tasman Sea is the large body of water between Australia and New Zealand, approximately across. It extends 2,800 km from north to south. It is a south-western segment of the South Pacific Ocean. The sea was named after the Dutch explorer Abel Janszoon Tasman, the first recorded European...
between Australia and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
.
Behaviour
The owls are secretive, relatively silent, and strictly nocturnal birds. They roost during the day, usually in trees in dense foliage or hollows, as well as in rocky overhangs and caves, and occasionally in farm sheds and other open buildings.Breeding
The owls breed as territorialTerritory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...
and monogamous pairs. They nest
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
in large tree hollow
Tree hollow
A tree hollow or tree hole is a semi-enclosed cavity which has naturally formed in the trunk or branch of a tree. These are predominantly found in old trees, whether living or not...
s with a floor of decaying wood debris. The female is fed by the male while incubating
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
a clutch of 2-4 eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
for about 42 days before hatching. The chicks are covered in, at first, white, then creamy down, and fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
in 10–12 weeks. Fledged owls with traces of down
Down feather
The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator and padding, used in goods such as jackets, bedding,...
may remain in the vicinity of the nest for several weeks. Breeding is seasonal with most eggs laid in spring from late October to early November.
Anecdotally, Tasmanian Masked Owls were first bred in captivity
Captive breeding
Captive breedingis the process of breeding animals in human controlled environments with restricted settings, such as wildlife reserves, zoos and other conservation facilities; sometimes the process is construed to include release of individual organisms to the wild, when there is sufficient...
in 1945 in Launceston
Launceston, Tasmania
Launceston is a city in the north of the state of Tasmania, Australia at the junction of the North Esk and South Esk rivers where they become the Tamar River. Launceston is the second largest city in Tasmania after the state capital Hobart...
by Miss Audrey Lee. However, the first detailed account of such an achievement is by David Fleay
David Fleay
David Howells Fleay was an Australian naturalist who pioneered the captive breeding of endangered species, and was the first person to breed the platypus in captivity....
, who bred them at the Healesville Sanctuary
Healesville Sanctuary
Healesville Sanctuary, or the Sir Colin MacKenzie Fauna Park, is a zoo specializing in native Australian animals. It is located at Healesville in rural Victoria, Australia, and has a history of breeding native animals. It is one of only two places to have successfully bred a platypus, the other...
in Victoria in 1946.
Feeding
The owls hunt at night, preying on a wide range of animals, from insects to mammals as large as rabbitsEuropean Rabbit
The European Rabbit or Common Rabbit is a species of rabbit native to south west Europe and north west Africa . It has been widely introduced elsewhere often with devastating effects on local biodiversity...
, bandicoot
Bandicoot
Bandicoots are a group of about 20 species of small to medium-sized, terrestrial marsupial omnivores in the order Peramelemorphia.- Etymology :...
s and brushtail possum
Brushtail possum
The brushtail possums are the members of the genus, Trichosurus, a genus of marsupial in the Phalangeridae family.It contains the following species:*Northern Brushtail Possum, Trichosurus arnhemensis...
s. The main diet includes introduced rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s and rabbits in agricultural areas, and marsupials and native birds in less disturbed habitats. They often hunt from perches using sound to detect prey, which is usually taken on the ground by striking with the feet and using the talons to pierce and kill.
Voice
Among their calls, Tasmanian Masked Owls utter a loud, rich, hissing or rasping screech, the call of the female being deeper and harsher than that of the male. They also snap their beaks loudly as a warning against perceived threats.Tasmania
The Tasmanian Masked Owl is considered to be Endangered under the Tasmanian Threatened Species Protection Act 1995Threatened Species Protection Act 1995
The Threatened Species Protection Act 1995, is an act of the Parliament of Tasmania that provides the statute relating to conservation of flora and fauna. Its long title is An Act to provide for the protection and management of threatened native flora and fauna and to enable and promote the...
, because of its small population (estimated at about 1330 breeding birds, or 615 pairs) as well as ongoing habitat loss, especially of old-growth forest suitable for breeding. An important conservation need is to maintain nesting habitat in production forests. It is also threatened by competition for nest hollows by feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
bees
European honey bee
The Western honey bee or European honey bee is a species of honey bee. The genus Apis is Latin for "bee", and mellifera comes from Latin melli- "honey" and ferre "to bear"—hence the scientific name means "honey-bearing bee"...
, kookaburras
Laughing Kookaburra
The Laughing Kookaburra, Dacelo novaeguineae, is a carnivorous bird in the kingfisher family Halcyonidae. Native to eastern Australia, it has also been introduced to parts of New Zealand, Tasmania and Western Australia. Male and female adults are similar in plumage, which is predominantly brown and...
and possums
Common Brushtail Possum
The Common Brushtail Possum is a nocturnal, semi-arboreal marsupial of the family Phalangeridae, it is native to Australia, and the largest of the possums.Like most possums, the Common Brushtail is nocturnal...
.
Lord Howe Island
Between December 1922 and October 1930 almost 100 Masked Owls, mostly from Tasmania, were introduced to Lord Howe Island in an unsuccessful attempt to control Black RatBlack Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...
s. The population there is considered to be a threat to the endemic Lord Howe Woodhen
Lord Howe Woodhen
The Lord Howe Woodhen, Gallirallus sylvestris, also known as the Lord Howe Island Woodhen or Lord Howe Rail, is a flightless bird of the rail family . It is endemic to Lord Howe Island off the Australian coast. It is a small olive brown bird, with a short tail and a downcurved bill...
and Lord Howe Currawong
Lord Howe Currawong
The Lord Howe Currawong , Lord Howe Island Currawong or Lord Howe Pied Currawong, is a large and mainly black passerine bird in the Artamidae family...
, as well as to breeding seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s, and is culled when possible.
Sources
- Anon. (10 October 2002). Threatened Fauna Manual for Production Forests in Tasmania – Masked Owl (draft).PDF download