Biodiversity

Species Profile and Threats Database


For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
 
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Endangered
Listing and Conservation Advices Commonwealth Listing Advice on Tyto novaehollandiae melvillensis (Threatened Species Scientific Committee, 2006ai) [Listing Advice].
 
Recovery Plan Decision Recovery Plan required, this species had a recovery plan in force at the time the legislation provided for the Minister to decide whether or not to have a recovery plan (19/2/2007).
 
Adopted/Made Recovery Plans National Multi-species Recovery Plan for the Partridge Pigeon Geophaps smithii smithii, Crested Shrike-tit, Falcunculus frontatus whitei, Masked Owl Tyto novaehollandiae kimberli and Masked Owl Tiwi Islands Tyto novaehollandiae melvillensis 2004-2009 (Woinarski, J.C.Z, 2004) [Recovery Plan].
 
Policy Statements and Guidelines Survey Guidelines for Australia's Threatened Birds. EPBC Act survey guidelines 6.2 (Department of the Environment, Water, Heritage and the Arts (DEWHA), 2010l) [Admin Guideline].
 
Federal Register of
    Legislative Instruments
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument].
 
Inclusion of species in the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (43) (14/08/2006) (Commonwealth of Australia, 2006g) [Legislative Instrument].
 
State Government
    Documents and Websites
NT:Threatened Species of the Northern Territory: Masked Owl (Tiwi subspecies), Tyto novaehollandiae melvillensis (Woinarski, J. & S. Ward, 2012c) [Information Sheet].
State Listing Status
NT: Listed as Endangered (Territory Parks and Wildlife Conservation Act 2000 (Northern Territory): 2012 list)
Non-statutory Listing Status
NGO: Listed as Endangered (The Action Plan for Australian Birds 2010)
Scientific name Tyto novaehollandiae melvillensis [26049]
Family Tytonidae:Strigiformes:Aves:Chordata:Animalia
Species author  
Infraspecies author Mathews,1912
Reference  
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images

The Masked Owl (Tiwi Islands) is a conventionally accepted subspecies of the Masked Owl (Tyto novaehollandiae) (Higgins 1999; Mees 1964; Schodde & Mason 1980).

The Masked Owl (Tiwi Islands) is a large owl of more than 30 cm in length and 400 g in weight. It has a white to buff facial mask, which is framed by a black ruff that merges into a pair of thick furrowed brows; buff and blackish-brown or black-and-white upperparts; and white to buff underparts with coarse dark spots or, in some individuals, chevrons. The female is much bigger and bulkier than the male, and has larger feet (Higgins 1999).

The better known subspecies of mainland Australia and Tasmania exhibit three basic plumage morphs (light, intermediate and dark), with a fourth white variant observed in males in northern Australia (Higgins 1999; Schodde & Mason 1980). At the present time, it is not known if the three basic morphs, or the white variant, are present in the Tiwi Islands population.

The Masked Owl (Tiwi Islands) is endemic to Melville Island and Bathurst Island (the Tiwi Islands) in the Northern Territory (Higgins 1999; Mees 1964; Schodde & Mason 1980). It is reasonably widespread on both islands (Woinarski et al. 2003b), and is especially common in areas of higher rainfall to the north-west of Melville Island (Woinarski et al. 2003b).

The extent of occurrence of the Masked Owl (Tiwi Islands) is estimated, with high reliability, to be 8000 km² (Threatened Species Scientifc Committee 2006ai). Area of occurrence is considered stable and there is no evidence of a recent decline (Garnett & Crowley 2000).

The area of occupancy of the Masked Owl (Tiwi Islands) is estimated, with low reliability, to be 5000 km² (Garnett & Crowley 2000; Threatened Species Scientific Committee 2006ai). Three hundred square kilometres of the owl's preferred habitat (tall eucalypt forest) has been converted to plantation forestry and may have reduced the species area of occupancy (J. Woinarski 2007a, pers. comm.).

There is probably some dispersion of the Masked Owl (Tiwi Islands) across the narrow Apsley Strait, which separates Bathurst Island and Melville Island. Consequently, the subspecies probably functions as a single population (J. Woinarski 2007a, pers. comm.).

The distribution of the Masked Owl (Tiwi Islands) was probably continuous throughout the extensive eucalypt forests of the Tiwi Islands. However, recent land clearing may have fragmented the distribution (J. Woinarski 2007a, pers. comm.).

Survey effort relevant to the Masked Owl (Tiwi Islands) includes:

  • a brief study of the Tiwi Islands avifauna in 1996 (Mason & Schodde 1997)
  • a brief, targeted systematic fauna survey in the western region of Melville Island (Woinarski et al. 2003b)
  • substantial surveys, by ecological consultants, associated with the plantation development (J. Woinarski 2007a, pers. comm.).

The population of the Masked Owl (Tiwi Islands) is estimated to consist of 1000 breeding individuals which occur as a single contiguous breeding population (Garnett & Crowley 2000).

The population size of the Masked Owl (Tiwi Islands) is suspected to be declining (Garnett & Crowley 2000). This prediction is based on the potential adverse impacts of threats on the islands.

The Masked Owl (Tiwi Islands) is unlikely to undergo extreme natural fluctuations in population size, extent of occurrence or area of occupancy. It is possible that frequent but irregular cyclones may deplete suitable nesting hollows, thus impacting population trends (J. Woinarski 2007a, pers. comm.).

The Masked Owl (Tiwi Islands) has not been recorded to crossbreed with other Masked Owl subspecies or any other bird species.

The Masked Owl (Tiwi Islands) does not occur within any conservation reserve.

The Masked Owl (Tiwi Islands) occurs mostly in tall open eucalypt forest and woodland (Mason & Schodde 1997; Woinarski et al. 2003b), especially where Darwin Woollybutt (Eucalyptus miniata), Darwin Stringybark (E. tetrodonta) and Melville Island Bloodwood (E. nesophila) are dominant (Woinarski et al. 2003b). This subspecies often roosts in monsoon rainforest, and forages in more open habitats such as grassland and treeless shrubland dominated by Fern-leaved Silky Oak (Grevillea pteridifolia), Melaleuca spp., Acacia spp. and Tropical Banksia (Banksia dentata) (Woinarski et al. 2003b). It is also reported to roost in mangroves and plantations of Mangium (Acacia mangium), but it is unlikely to nest in either of these habitats because of the relative scarcity or absence of suitable hollow-bearing trees (J. Woinarski 2007a, pers. comm.). It is occasionally observed in Pinus elliotti plantations (Mason & Schodde 1997).

The Masked Owl (Tiwi Islands) does not occur in any ecological communities listed under the EPBC Act. It does, however, co-occur with a large number of species listed under the EPBC Act, including Butler's Dunnart (Sminthopsis butleri, Vulnerable), the Water Mouse (Xeromys myoides, Vulnerable), Red Goshawk (Erythrotriorchis radiatus, Vulnerable), Partridge Pigeon (eastern) (Geophaps smithii smithii, Vulnerable), Hooded Robin (Tiwi Islands) (Melanodryas cucullata melvillensis, Endangered) and the plants Burmannia sp. Bathurst Island (R.Fensham 1021) (Endangered), Hoya australis subsp. oramicola (Vulnerable), Mitrella tiwiensis (Vulnerable), Typhonium jonesii (Endangered), T. mirabile (Endangered) and Xylopia monosperma (J. Woinarski 2007a, pers. comm.).

The life expectancy and age of sexual maturity of the Masked Owl (Tiwi Islands) are unknown. The generation length of this subspecies is estimated to be five years (Garnett & Crowley 2000).

No information is available about the breeding biology of the Masked Owl (Tiwi Islands), however, it is assumed to be similar to subspecies on mainland Northern Territory. The only published record of the time of breeding in the Northern Territory indicates that eggs were found in June (Le Souef 1902). Pair-bonds of the northern mainland populations are probably lifelong, but the partner may be replaced if the other dies (Higgins 1999). The species nests in large hollows, usually in the trunks of eucalypts, but sometimes in a vertical spout or limb (Higgins 1999). The hollow is usually lined with sand, soil or debris and most, if not all, of the nest preparation is done by the male (Fleay 1949).

The clutch-size is one to four eggs, but usually two or three (Hollands 1991; Schodde & Mason 1980). The female occupies the nest up to 10 weeks before laying and only the female incubates and broods the young, during which time the male hunts for the female and chicks. After brooding stops (two to three weeks after hatching), both sexes hunt (Fleay 1949; Schodde & Mason 1980). The incubation period is generally 33–35 days (Fleay 1949), but could be as much as 42 days (Hollands 1991). The fledging period is 10–12 weeks (Hollands 1991; Schodde & Mason 1980). The young are dependent on the parents for one to three months after fledging, but start to seek their own food after the first month (Schodde & Mason 1980).

The Masked Owl (Tiwi Islands) is presumed, on the basis of studies on other subspecies of the Masked Owl (Debus & Rose 1994; Green 1982a; Green & Rainbird 1985; Kavanagh 1996; Mooney 1992a; Peake et al. 1993), to feed on a combination of insects, birds and small to medium-sized mammals, with mammals likely to represent the major source of food.

The foraging behaviour of the Masked Owl (Tiwi Islands) has not been described. However, it is likely to be similar to that of the Masked Owl (southern Australia) (Tyto novaehollandiae novaehollandiae), which is an opportunistic predator that hunts from perches and occasionally on the wing for terrestrial, scansorial (climbing) and arboreal prey (Debus 1993; Debus & Rose 1994; Kavanagh & Murray 1996).

The Masked Owl (Tiwi Islands) is probably resident or sedentary, as reported for other subspecies of the Masked Owl (Higgins 1999). From the limited observations that have been made, the Masked Owl (Tiwi Islands) appears to mostly occur solitarily or in pairs (J. Woinarski 2007a, pers. comm.).

The home ranges and territories of the Masked Owl (Tiwi Islands) have not been described. The home range estimate for the Masked Owl on the mainland is 5–10 km² in eastern Australia (Schodde & Mason 1980). Specfic studies have shown that pairs in Tasmania are believed to occupy home ranges of as little as 1.8 km² (Mooney 1992a), one female in NSW was recorded over an area of 10.2–11.8 km² (Kavanagh & Murray 1996) and one female in Victoria had an estimated post-nesting home range of 11.3–13.1 km² (McNabb et al. 2003). It is likely that home range varies with location characteristics and other factors (Higgins 1999). Home ranges on the Tiwi Islands, where the Masked Owl occurs at higher densities than on mainland Australia (Fensham & Woinarski 1992; Mason & Schodde 1997), could possibly be smaller than the home ranges recorded in eastern mainland Australia.

Distinctiveness
The Masked Owl (Tiwi Islands) is not similar to any other species on the Tiwi Islands.

Detectability
The Masked Owl (Tiwi Islands) can be difficult to survey because it is nocturnal, cryptic and generally quiet. It is, however, said to become noisy in the months before the breeding season. It is usually detected by its call. For at least some parts of the year, it is readily attracted to observers by the broadcast of recorded calls (J. Woinarski 2007a, pers. comm.).

Recommended methods
The recommended method to survey for the Masked Owl (Tiwi Islands) is to conduct broadcast surveys (the playback of recorded calls to solicit a response) in suitable habitat, especially in lead up to the breeding season. Area searches and transect surveys are unlikely to be effective for the Masked Owl (Tiwi Islands) because of its nocturnal behaviour and cryptic nature (J. Woinarski 2007a, pers. comm.). The surveys that are being conducted by ecological consultants associated with Great Southern Plantations will assist in determing the most appropriate time for surveys to be conducted and the most effective survey technique (J. Woinarski 2007a, pers. comm.).

The primary threat to the Masked Owl (Tiwi Islands) is the conversion of large areas of optimal habitat (tall open eucalypt forest) to short-rotation plantations (Garnett & Crowley 2000). Of particular concern is the loss of large hollow-bearing trees that may be used for nesting (Garnett & Crowley 2000). 26 000 ha of land has been converted between 2002–07 (J. Woinarski 2007a, pers. comm.).

The Masked Owl (Tiwi Islands) may also have been adversely affected by changes to the structure of the native vegetation on the Tiwi Islands caused by invasive weeds and a shift in fire regime away from traditional burning practices (Fensham & Cowie 1998; Garnett & Crowley 2000; Northern Territory Parks & Wildlife Commission 2006a).

It is possible that habitat change associated with the development of plantations, invasive weeds and altered fire regimes may have reduced the abundance of native mammals (Firth et al. 2006; Garnett & Crowley 2000; Woinarski 2004), which are presumed, on the basis of studies on other subspecies of the Masked Owl (Debus & Rose 1994; Green 1982a; Green & Rainbird 1985; Kavanagh 1996; Mooney 1992a; Peake et al. 1993), to be a source of food for the Masked Owl (Tiwi Islands).

Cyclones are a common occurrence in the Tiwi Islands and may periodically substantially reduce the extent of suitable habitat and, in particular, the availability of large hollow-bearing trees (J. Woinarski 2007a, pers. comm.).

The small size and restricted distribution of the Masked Owl (Tiwi Islands) population suggests that it may have low genetic diversity (J. Woinarski 2007a, pers. comm.).

The following recovery actions have been implemented:

  • A baseline population survey has been conducted for some areas in the western region of Melville Island (Woinarski et al. 2003b). Further surveys have been undertaken and continue to be undertaken by ecological consultants (J. Woinarski 2007a, pers. comm.).
  • A prescription is included within the Tiwi Islands Plantation Forestry Strategic Plan to maintain native forest to a distance of 100 m around known roost and/or nest sites (Hadden 2000). In 2007, no roosts had been located (J. Woinarski 2007a, pers. comm.).

The following recovery actions were identified in the recovery plan and may be implemented (Woinarski 2004):

  • Establish and operate a recovery team or forum to assist in the coordination of management actions.
  • Assess the population size, distribution and habitat requirements of this subspecies.
  • Ensure, using Population Viability Analysis where appropriate, that development does not compromise the viability of the Masked Owl (Tiwi Islands) population.
  • Develop a monitoring program to provide effective and accurate measures of population trends.
  • Implement a fire management strategy to maintain suitable habitat.
  • Minimise the impacts of land clearing activities.
  • Minimise the impacts caused by the spread of exotic pasture plants.

The implementation of some of these recovery actions has begun (Northern Territory Parks & Wildlife Commission 2006a).

To attain approval, the plantation forestry operation on the Tiwi Islands is required to adhere to several conditions imposed under the jurisdiction of the EPBC Act. Included among these conditions are some mitigation measures for the Masked Owl (Tiwi Islands) (J. Woinarski 2007, pers. comm.), this is despite the subspecies not being listed at the time of project's approval.

No major studies have been conducted on the Masked Owl (Tiwi Islands).

A number of documents provide information on the Masked Owl (Tiwi Islands) and/or management actions, including:

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Agriculture and Aquaculture:Agriculture and Aquaculture:Land clearing, habitat fragmentation and/or habitat degradation The Action Plan for Australian Birds 2000 (Garnett, S.T. & G.M. Crowley, 2000) [Cwlth Action Plan].
Commonwealth Listing Advice on Land clearance (Threatened Species Scientific Committee, 2001w) [Listing Advice].
Climate Change and Severe Weather:Storms and Flooding:Natural events such as storms and cyclones leading to habitat destruction and flora/fauna mortality Commonwealth Listing Advice on Tyto novaehollandiae melvillensis (Threatened Species Scientific Committee, 2006ai) [Listing Advice].
Ecosystem/Community Stresses:Ecosystem Degradation:Decline in habitat quality Commonwealth Listing Advice on Tyto novaehollandiae melvillensis (Threatened Species Scientific Committee, 2006ai) [Listing Advice].
Ecosystem/Community Stresses:Indirect Ecosystem Effects:Restricted geographical distribution (area of occupancy and extent of occurrence) National Multi-species Recovery Plan for the Partridge Pigeon Geophaps smithii smithii, Crested Shrike-tit, Falcunculus frontatus whitei, Masked Owl Tyto novaehollandiae kimberli and Masked Owl Tiwi Islands Tyto novaehollandiae melvillensis 2004-2009 (Woinarski, J.C.Z, 2004) [Recovery Plan].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds Commonwealth Listing Advice on Tyto novaehollandiae melvillensis (Threatened Species Scientific Committee, 2006ai) [Listing Advice].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Commonwealth Listing Advice on Tyto novaehollandiae melvillensis (Threatened Species Scientific Committee, 2006ai) [Listing Advice].
Species Stresses:Indirect Species Effects:Low numbers of individuals National Multi-species Recovery Plan for the Partridge Pigeon Geophaps smithii smithii, Crested Shrike-tit, Falcunculus frontatus whitei, Masked Owl Tyto novaehollandiae kimberli and Masked Owl Tiwi Islands Tyto novaehollandiae melvillensis 2004-2009 (Woinarski, J.C.Z, 2004) [Recovery Plan].

Debus, S.J.S. (1993). The mainland Masked Owl Tyto novaehollandiae: a review. Australian Bird Watcher. 15:168-191.

Debus, S.J.S. & A.B. Rose (1994). The Masked Owl Tyto novaehollandiae in New South Wales. Australian Birds. 28 (Suppl):40-64.

Fensham, R.J. & I.D. Cowie (1998). Alien plant invasions on the Tiwi Islands: extent, implications and priorities for control. Biological Conservation. 83:55-68.

Fensham, R.J. & J.C.Z. Woinarski (1992). Yawalama: the ecology and conservation of monsoon forest on Tiwi Islands, Northern Territory. Report to DASET, Conservation Commission of the Northern Territory.

Firth, R.S.C., J.C.Z. Woinarski, K.G. Brennan & C. Hempel (2006). Environmental relationships of the Brush-tailed Rabbit-rat Conilurus penicillatus and other small mammals on the Tiwi Islands, northern Australia. Journal of Biogeography. 33:1820-1837.

Fleay, D. (1949). The Tasmanian Masked Owl. Emu. 48:169-176.

Garnett, S.T. & G.M. Crowley (2000). The Action Plan for Australian Birds 2000. [Online]. Canberra, ACT: Environment Australia and Birds Australia. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/action/birds2000/index.html.

Green, R.H. (1982a). Breeding and food of the Masked Owl Tyto novaehollandiae. Tasmanian Naturalist. 69:4-6.

Green, R.H. & J.L. Rainbird (1985). Food of the Masked Owl Tyto novaehollandiae. Tasmanian Naturalist. 82:5-7.

Hadden, K. (2000). Tiwi Islands Plantation Forestry Strategic Plan. Darwin: Tiwi Land Council.

Higgins, P.J. (ed.) (1999). Handbook of Australian, New Zealand and Antarctic Birds. Volume Four - Parrots to Dollarbird. Melbourne: Oxford University Press.

Hollands, D. (1991). Birds of the Night. Sydney, NSW: A.H. and A.W. Reed.

Kavanagh, R.P. (1996). The breeding biology and diet of the Masked Owl Tyto novaehollandiae near Eden, New South Wales. Emu. 96:158-165.

Kavanagh, R.P. & M. Murray (1996). Distribution of nocturnal forest birds and mammals in north-eastern Newcastle, New South Wales. Emu. 96:250-257.

Le Souef, D. (1902). Descriptions of birds' eggs from the Port Darwin district, northern Australia. Emu. 2:85-96.

Magrath, M.J.L., M.A. Weston, P. Olsen & M. Antos (2004). Draft Survey Standards for Birds: Species Accounts. Melbourne, Victoria: Report for the Department of the Environment and Heritage by Birds Australia.

Mason, I.J. & R. Schodde (1997). Bird survey of the Tiwi Islands, October 1996. Report to Tiwi Land Council. Canberra: CSIRO.

McNabb, E., J. McNabb & K. Barker (2003). Post-nesting home range, habitat use and diet of a female Masked Owl Tyto novaehollandiae in western Victoria. Corella. 27:109-117.

Mees, G.F. (1964). A revision of the Australian Owls (Striigdae and Tytonidae). Zoologische Verhandelingen. 65:1--62.

Mooney, N. (1992a). Diet of the Masked Owl in Tasmania. Tasmanian Bird Report. 21:35-55.

Northern Territory Parks & Wildlife Commission (2006a). Threatened Species of the Northern Territory: Masked Owl (Tiwi subspecies), Tyto novaehollandiae melvillensis. [Online]. Darwin: Department of Natural Resources, Environment and the Arts. Available from: http://www.nt.gov.au/nreta/wildlife/animals/threatened/pdf/birds/masked_owl_tiwi_en.pdf.

Peake, P., L.E. Conole, S.J.S. Debus, A. McIntyre & M. Bramwell (1993). The Masked Owl Tyto novaehollandiae in Victoria. Australian Bird Watcher. 15:124-136.

Schodde, R. & I.J. Mason (1980). Nocturnal Birds of Australia. Melbourne: Lansdowne.

Threatened Species Scientific Committee (2006ai). Commonwealth Listing Advice on Tyto novaehollandiae melvillensis. [Online]. Available from: http://www.environment.gov.au/biodiversity/threatened/species/tyto-novaehollandiae-melvillensis.html.

Threatened Species Scientific Committee (2006bd). NON-APPROVED Conservation Advice on Tyto novaehollandiae melvillensis. [Online]. Available from: http://www.environment.gov.au/biodiversity/threatened/species/tyto-novaehollandiae-melvillensis.html.

Tiwi Land Council (2004). A natural resource management plan for the Tiwi Islands. Darwin: Tiwi Land Council.

Woinarski, J. (2007a). Personal communication. Northern Territory: Department of Natural Resources, Environment and the Arts.

Woinarski, J., K. Brennan, C. Hempel, M. Armstrong, D. Milne & R. Chatto (2003b). Biodiversity conservation on the Tiwi islands, Northern Territory. Part 2. Fauna. Report to National Heritage Trust, Tiwi Land Council and the Department of Infrastructure Planning and Environment.

Woinarski, J.C.Z (2004). National Multi-species Recovery Plan for the Partridge Pigeon Geophaps smithii smithii, Crested Shrike-tit, Falcunculus frontatus whitei, Masked Owl Tyto novaehollandiae kimberli and Masked Owl Tiwi Islands Tyto novaehollandiae melvillensis 2004-2009. [Online]. Darwin: Northern Territory Department of Infrastructure Planning and Environment. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/smithii-whitei-kimberli-melvillensis/index.html.

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This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Tyto novaehollandiae melvillensis in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Sun, 21 Sep 2014 00:48:48 +1000.