Australian Masked Owl

SPECIES Australian Masked Owl
TAXONOMY Tyto (Megastrix) novaehollandiae castenops
STATUS Least concern (Redlist.org); Endangered SA (ala.org.au)

Native to Australia, the Masked Owl is the largest species of the Tyto owl. Tyto owls have a definitive heart-shaped face in contrast to hawk-owls. Tasmania hosts the largest subspecies of Masked Owl, Tyto novaehollandiae castanops. The Masked Owl is second in size of the nocturnal birds in Australia, with the largest species being the Powerful Owl, Ninox strenua. Where once widespread, population numbers are on the decline which has given this species special conservation status.

Habitat
Masked Owls inhabit the broad coastal band around most of mainland Australia and throughout Tasmania. It prefers woodlands and timbered waterways, seeking old growth trees with suitable nesting hollows close to foraging areas. The Tasmanian Masked Owl has been recorded throughout the island among forests, isolated old-growth trees, wet eucalyptus forest, non-eucalyptus dominated forest, caves, and occasionally man-made structures such as farm sheds and open buildings.

Feeding
In developed agricultural zones, Masked Owls feed mainly on introduced species such as small rodents and rabbits. In natural habitat, they will seek prey animals such as small birds, marsupials, reptiles, and insects. Being nocturnal, hunting occurs during the early hours of night. They will perch to listen for the movement of prey.

Behaviour
They are found singular or in monogamous pairs, remaining in or near their territory all year round. They communicate with a deep and rasping screech.

Appearance
The Masked Owl has a distinct plumage pattern which varies in the depth of colour. Generally, the upper wings are darker with a barred pattern and the underbody is lighter, if not white. Its legs are fully feathered. Geography determines the depth of colouring as the owl will appear darker the further south it is located. The Tasmanian Masked Owl has the darkest plumage of all. The young are very light in colour up through their first year.

As a Tyto owl species, the Masked Owl has a heart-shaped facial disk containing extremely fine feathers. It is always lighter (from buff to white) with a dark margin and darker still around the bill and below the eyes. 

Considered to be a large owl, the females can weigh up to 1260 grams, have a wingspan of up to 129 centimetres, and measure up to 57 centimetres tall. Although patterned the same, the males are lighter in colouring and smaller in size by as much as 20%.

Reproduction
Masked Owls will breed when the conditions are favourable and food is available. Pairs will nest in an old growth tree hollow lined with soil, sand, or mulch. The female will incubate the clutch or 2 or 3 eggs whilst the male provides food. The eggs will hatch in 42 days, with the young remaining dependent up to 12 weeks. Tasmanian weather has limited the breeding season to Spring conditions.

Threats
The Tasmanian Masked Owl has been listed as Endangered due to the small population size and continual loss of habitat particularly focussed on the reduction of suitable nesting sites. Other factors in the decline include availability of and competition for prey, changing fire patterns, and forestry practices. 

Updated 5 May 2021