Southern boobook (Ninox novaeseelandiae)

Southern boobook fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Southern boobook description

The southern boobook (Ninox novaeseelandiae) is easily recognised by its distinctive, bi-syllabic ‘boo-book’ call that earned this species its common name ^{(2) (4)}. A small, stout bird with rounded wings and a long tail ⁽²⁾, the southern boobook is considered to be the smallest owl on mainland Australia. First described from the New Zealand subspecies (N. n. novaeseelandiae) ⁽⁵⁾, this species is dark to reddish-brown in colour ⁽²⁾, with buffy streaks on the upperparts ^{(2) (4)} and buffy spots on the breast and belly ⁽⁴⁾. Its yellow to yellowish-brown legs are feathered, with toes that are bristled or sometimes bare ⁽⁴⁾. The facial disc is greyish-white with white or reddish-brown eyebrows ⁽²⁾, and the southern boobook has bright yellow eyes and a dark bill with a pale tip ⁽⁴⁾.

Male and female boobooks are similar in appearance, but the female tends to be more streaked on the upperparts ⁽²⁾. Juvenile southern boobooks have increased streaking on the top of the head, nape and breast compared to the adults ⁽²⁾.

Four subspecies of the southern boobook are recognised: Ninox novaeseelandiae novaeseelandiae, Ninox novaeseelandiae leucopsis, Ninox novaeseelandiae undulata and Ninox novaeseelandiae albaria ⁽⁶⁾. The intensity and extent of plumage colour, body size and feather markings of individuals vary between these geographically separated subspecies ⁽²⁾. Two subspecies, N. n. albaria and N. n. undulata, are now considered to be extinct, but N. n. undulata genes survive in a hybrid population with N. n. novaeseelandiae on Norfolk Island ^{(7) (8)}.

The southern boobook’s most common call is a repetitive, double, ‘boo-book’ hoot ⁽²⁾, where the second syllable is of marginally lower pitch. This call is frequently preceded by a series of croaking sounds. This species may also infrequently give a yelping ‘yow’, or a low, repetitive and monotonous ‘mor-mor-mor’. When at the nest, females and young give low trills ⁽⁴⁾.

Also known as

morepork, New Zealand boobook, New Zealand morepork, Norfolk Island boobook, ruru, spotted boobook.

Size

Length: c. 29 cm ⁽²⁾

Male weight: c. 156 g ⁽²⁾

Female weight: c. 170 g ⁽²⁾

Southern boobook biology

Reported to take a wide range of prey, the southern boobook feeds on insects, spiders, reptiles and small to medium-sized mammals ^{(2) (7)}, as well as amphibians, other birds and juvenile common ringtail possums (Pseudocheirus peregrinus). This species is an active hunter ⁽⁷⁾, searching from a perch and taking prey from the canopy or ground, including the roadside, or hawking insects from the air ⁽²⁾ . It forages mainly at dusk and just before dawn, but will also feed from time to time throughout the night ⁽⁷⁾.

A monogamous species, the southern boobook may form breeding pairs as early as six months after fledging, except on Norfolk Island where individuals do not breed until three or four years old ⁽¹⁰⁾. Although this species lays from late September to November, individuals in the south generally breed later than those in the north. The southern boobook nests most commonly in tree hollows, and less often in caves or nooks in river banks, and its clutch size is normally two eggs, very rarely three. The female southern boobook incubates the eggs for around 30 days, and newly hatched chicks have greyish-white downy feathers that become more sooty-grey as they get older. The chicks fledge at around five weeks old, but remain with the adult birds for a further three months ⁽²⁾.

The southern boobook is a nocturnal species that occurs singly or in pairs ⁽¹¹⁾. This species’ movements are poorly understood, but it is believed that young birds may disperse during the winter to islands where the species is not normally found ⁽²⁾. 

Southern boobook range

The southern boobook is native to Indonesia, Papua New Guinea, Timor-Leste, Australia, New Zealand and Norfolk Island, an external territory of Australia in the South Pacific Ocean ⁽⁹⁾.

The subspecies N. n. novaeseelandiae is native to New Zealand and most of its offshore islands, and N. n. leucopsis occurs on Tasmania and the Bass Strait Islands ⁽²⁾. The extinct subspecies N. n. undulata was endemic to Norfolk Island ^{(2) (8)}, where a hybrid population of N. n. novaeseelandiae and N. n. undulata now occurs ⁽⁸⁾. N. n. albaria was endemic to Lord Howe Island, off the east coast of Australia ^{(2) (9) (10)}.

Southern boobook habitat

The southern boobook is an inhabitant of open forest and woodland, as well as farmland dotted with trees. This species is generally found near watercourses ⁽¹¹⁾, and requires dense canopy and large trees with hollows for nesting and roosting ^{(2) (11)}. 

Southern boobook status

The southern boobook is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾, and is listed on Appendix II of CITES, with the exception of the subspecies Ninox novaeseelandiae undulata which is listed on Appendix I ⁽³⁾.

Southern boobook threats

The southern boobook is considered to have an extremely large range ⁽⁹⁾ and is therefore not considered to be threatened ^{(2) (9)}. However, it may face a number of localised threats in some areas. For example, there has been some indication of secondary poisoning as a result of possum pest-control programmes in locally restricted areas ⁽⁸⁾.

The hybrid subspecies of N. n. undulata and N. n. novaeseelandiae is regarded as endangered on Norfolk Island due to clearing of its habitat and selective logging. The genetically pure subspecies N. n. undulata became extinct on Norfolk Island due to habitat loss, particularly of trees with hollows that are needed for the species to nest. Seventy-five percent of Norfolk Island’s native forest has been cleared and woody weeds have overrun much of the remaining forest, possibly rendering it unsuitable habitat for N. n. undulata ⁽⁸⁾.

N. n. albaria became extinct on Lord Howe Island in the 1950s as a result of the destruction of its forest habitat and the introduction of non-native species ⁽²⁾.

Southern boobook conservation

Conservation efforts to preserve the genes of the last remaining, genetically pure N. n. undulata individual on Norfolk Island began in 1987. The programme involved creating a hybrid population by introducing two male N. n. novaeseelandiae individuals to the island, and between December 1989 and December 1999, 27 hybrid nestlings were banded. There are now several generations of offspring on the island carrying the genes of both N. n. novaeseelandiae and the extinct N. n. undulata ⁽⁸⁾.

No other conservation measures are known to be in place specifically for the southern boobook. However, this species is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in the southern boobook should be carefully controlled ⁽³⁾.

Find out more

Find out more about the southern boobook:

• BirdLife International - Southern boobook:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=32126
• Department of Sustainability, Environment, Water, Population and Communities (2012) Ninox novaeseelandiae undulata. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at:
  http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=26188
• Department of Sustainability, Environment, Water, Population and Communities (2012) Ninox novaeseelandiae albaria. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at:
  http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=26043

Learn more about bird conservation in Australia:

• BirdLife Australia:
  http://www.birdlife.org.au/

Find out more about conservation in Australia:

• Australian Wildlife Conservancy:
  http://www.australianwildlife.org/
• Australian Conservation Foundation:
  http://www.acfonline.org.au/

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Glossary

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Hybrid

The offspring produced by parents of two different species or subspecies.

Incubate

To keep eggs warm so that development is possible.

Monogamous

Having only one mate during a breeding season, or throughout the breeding life of a pair.

Nape

The back of the neck.

Nocturnal

Active at night.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

References

1. IUCN Red List (April, 2013)
   http://www.iucnredlist.org/
2. del Hoyo, J., Elliott, A. and Sargatal, J. (1999) Handbook of the Birds of the World. Volume 5: Barn-Owls to Hummingbirds. Lynx Edicions, Barcelona.
3. CITES (April, 2013)
   http://www.cites.org/
4. Konig, C. and Weick, F. (2008) Owls of the World. Second Edition. Yale University Press, New Haven, Connecticut.
5. Olsen, J. (2011) Australian High Country Owls. CSIRO Publishing, Collingwood, Australia.
6. Integrated Taxonomic Information System (ITIS) (April, 2013)
   http://www.itis.gov/
7. Newton, I., Kavanagh, R., Olsen, J. and Taylor, I. (2002) Ecology and Conservation of Owls. CSIRO Publishing, Collingwood, Australia.
8. Department of Sustainability, Environment, Water, Population and Communities (2012) Ninox novaeseelandiae undulata. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at:
   http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=26188
9. BirdLife International - Southern boobook (April, 2013)
   http://www.birdlife.org/datazone/speciesfactsheet.php?id=32126
10. Department of Sustainability, Environment, Water, Population and Communities (2012) Ninox novaeseelandiae albaria. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at:
    http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=26043
11. Tzaros, C. (2005) Wildlife of the Box-Ironbark Country. CSIRO Publishing, Collingwood, Australia.