Australian Biological Resources Study

Australian Faunal Directory

<I>Nionox (Rhabdoglaux) strenua</I>

Nionox (Rhabdoglaux) strenua


Regional Maps


Compiler and date details

R. Schodde & I.J. Mason, CSIRO Australian National Wildlife Collection, Canberra, Australia


Strigidae (typical or hawk owls) comprises about 123–161 species in 22–27 genera; six species in one genus occur in Australia and its territories. The Australian fossil record is limited to Ninox Hodgson, 1837 in the Holocene-Pleistocene on Norfolk Island and in southern Victoria. The family is virtually cosmopolitan, with centres of diversity in North and South America, Eurasia and Africa.

Strigid owls are nocturnal or sometimes crepuscular predators that, solitary, in pairs or family groups, roost by day with head erect in trees, hollows, holes or burrows, and sally on wing at night to catch large insects or small vertebrates in their talons, swallowing prey usually in large dismembered pieces or sometimes whole at perch, and regurgitating indigestible parts in medium-sized, loosely bound pellets. Nests are of unconstructed beds in hollows, holes, burrows or usurped platform nests of other birds; eggs are spheroidal, plain dull white, and are incubated by the female; young are altricial, nidicolous and moult through two successive downs (protoptile, mesoptile) to fledge in the second.

Family-group Systematics

Whether to combine the strigid and tytonid owls in one family, or to separate them in two, remains open to argument. Hartert (1912–1921), Stresemann (1927–1934), Mayr & Amadon (1951), Vaurie (1965), Eck & Busse (1973), Wolters (1975–1982) and Amadon & Bull (1988) combined them, an approach supported by morphological and ontogenetic evidence (Stresemann & Stresemann 1966; Bock & McEvey 1969), cross-fertility (Flieg 1971), and the traits of the bay owls, Phodilus Geoffroy Saint-Hilaire, 1830 (Beddard 1890; Pycraft 1903a; Stresemann loc. cit; Miller 1965; Burton 1973; Eck & Busse loc. cit.; cf. Marshall 1966). Alternatively, strigids and tytonids have been separated in two families by Sharpe (1875), Beddard (1888), Pycraft (1898,1903b), Peters (1940), Verheyen (1956), Wetmore (1960), Mees (1964), van der Weyden & Ginn in Burton (1973), Condon (1975), Clark et al. (1978), Schodde & Mason (1981), American Ornithologists' Union (1983), Cramp (1985), Sibley et al. (1988) and Sibley & Monroe (1990); Phodilus has usually been included with the tytonids. Although strigids and tytonids may be monophyletic with respect to other families, prevailing convention supported by the genetic distance recorded between them by DNA/DNA hybridisation (Sibley et al. loc. cit.; Sibley & Ahlquist 1990), and the widely divergent karyotype of tytonids, including Phodilus (data in Christidis 1990), suggest that they are better treated as separate families for the present. This arrangement is consistent with their usual treatment in Australian literature cf. Alcedinidae.

By convention, strigid owls comprise two subfamilies: New World and Eurasian Striginae Leach, 1820 with large asymmetric ears and well-developed facial discs, and cosmopolitan Buboninae Vigors, 1825 with smaller, symmetric ears and incomplete to obscure facial discs (e.g. Sharpe 1875; Peters 1940; Cramp 1985). Buboninae are much the larger group, and include Australasian Ninox Hodgson, 1837. Wolters (1975–1982) and tentatively C.S. Roselaar in Cramp (loc. cit.) have split Strigidae as defined here into three subfamilies but with differing limits, indicating that infra-familial groupings and phylogeny are far from understood.

Note: until about 1910, Bubonidae was used as the usual name for this family because Strix Linnaeus, 1758, the basionym for Strigidae, had been misapplied to the tytonid owls (Mathews 1910).

Genus-group Systematics

Ninox Hodgson, 1837—As accepted here, this genus comprises about 16–19 species of west Pacific owls with small, untufted inoperculate ears, obsolete facial discs, and simple descendent moult of primaries. These traits suggest that their closest relatives are Asian-American Athene Boie, 1822, Glaucidium Boie, 1826 and related owls, including Sceloglaux Kaup, 1848, from which they are distinguished by the rather trivial characters of a longer and more pointed wing, shorter first primary and more restricted nocturnal activity (cf. Sharpe 1875; Eck & Busse 1973). The relationships of these genera need further clarification, as do the subgeneric groups in Ninox and the supposedly related Uroglaux Mayr, 1937 in New Guinea, cf. Schodde & Mason (1981: 37). All three subgenera of Ninox recognised here are present in the Australasian region, the centre of diversity for the genus.

Species-group Systematics

Ninox boobook (Latham, 1802)—Although this Australian-centred species has been treated conventionally as conspecific with N. novaeseelandiae (Gmelin, 1788), it is kept separate here after Schodde & Mason (1981: 58) because its distinguishing traits of proportion and pattern have received only passing appraisal since, cf. Mees (1982) and White & Bruce (1986). In north-eastern Queensland, N. b. lurida (De Vis, 1887) may also be distinct specifically (Schodde & Mason loc. cit.), but evidence of sympatry with other forms of N. boobook is needed.

Ninox novaeseelandiae (Gmelin, 1788)—The forms of boobook owls on Lord Howe and Norfolk Islands are members of the N. novaeseelandiae (Gmelin, 1788) superspecies (Mees 1964), but their relationships to either N. novaeseelandiae, sensu stricto, or the allospecific N. boobook (Latham, 1802) have not been determined, see Schodde & Mason (1981). Accordingly, they are kept here as subspecies of N. novaeseelandiae as is conventional. This procedural decision is supported by data on their proportions and plumage patterns in relation to morphological differences between N. novaeseelandiae and N. boobook catalogued by Schodde & Mason (loc. cit.: 58):

(1) Lord Howe Island form (n=12)—tail/wing ratio 0.62±0.01, primaries 1 8, 2 6, 3 ‹ 5, facial disc light red-brown and concolorous with dorsum;

(2) Norfolk Island form (n=9)—tail/wing ratio 0.63±0.01, primaries consistently 1 ‹ 8, 2 ‹ 6, 3 ‹ 5, facial disc chestnut-brown with faint greyish cast and concolorous with crown.

The relationships of these island forms, however, need closer scrutiny.

Ninox squamipila (Bonaparte, 1850)—In its conventional definition, as adopted here, Ninox squamipila (Bonaparte, 1850) comprises two widely separated groups of populations. One ranges from the Moluccas to Tanimbar in the eastern Banda Sea where it is represented by four subspecies (White & Bruce 1986), and the other is endemic to Christmas Island in the Indian Ocean. Notwithstanding the differences recorded by Olsen & Stokes (1989), the Christmas Island population shares with east Banda Sea forms a complement of traits not found in other small species of Ninox: medium-large size (among the small Ninox) with relatively long tail, rusty-rufous body plumage including uniform throat, closely rusty-and-white barred lower ventrum, plain head and mantle grading to geographically differentiated white spotting or barring over wings to lower back, and closely barred tail (from material in AMNH, ANWC); there is no difference in iris. If the Christmas Island population is of separate origin from Banda Sea squamipila, as is quite possible, then the extent of morphological convergence between them is extraordinary. Relationships between the two groups need further investigation to settle their status.

Ninox connivens (Latham, 1802)—For Australian populations, the most recent revision by Ford (1986) is not followed here because, although distinguishing Cape York Peninsula populations from those to the south, it does not compare their statistics in size with others from elsewhere in northern Australia, and does not analyse regional variation in colour cf. Schodde & Mason (1981: 52).

Ninox rufa (Gould, 1846)—Circumscription of this species, including New Guinean forms and excluding the Powerful Owl (Ninox strenua (Gould, 1838)), was first established by Mathews (1916: 352–353) who synthesized the various opinions of C.W. De Vis, A.J. North and Ernst Hartert.


Excluded Taxa

Vagrant Species

STRIGIDAE: Ninox connivens assimilis Salvadori & D'Albertis, 1876 [Included in some Australian checklists, possibly vagrant to Torres Strait]

STRIGIDAE: Ninox japonica japonica (Temminck & Schlegel, 1844) [Brown Hawk-Owl; vagrant to Ashmore Reef and WA. Specimen record from Ashmore Reef in January 1973, see Schodde & Van Tets (1981). Accepted by RAOU Records Appraisal Committee (1988: case no. 17). The specimen appears to be of the east Asian subspecies, N. s. japonica (Temminck & Schlegel, 1844) which migrates to the Philippine and Indonesian archipelagos during the boreal winter, see Mees (1970)] — Mees, G.F. 1970. Notes on some birds from the island of Formosa. Zoologische Mededelingen (Leiden) 44: 285-304; Schodde, R. & Van Tets, G.F. 1981. First record of the Brown Hawk-Owl Ninox scutulata from Australasia. The Emu 81: 171; RAOU Records Appraisal Committee 1988. Second Report of the Records Appraisal Committee. The Emu 88: 54-57

STRIGIDAE: Ninox scutulata (Raffles, 1822) [Brown Hawk-owl; vagrant to Ashmore Reef and WA] — Stanger, M., Clayton, M., Schodde, R., Wombey, J. & Mason, I. 1998. CSIRO List of Australian Verebrates: A Reference with Conservation Status. Collingwood : CSIRO Publishing iii 124 pp. [97]



Small to very large, mottled-plumaged raptors, with forward-facing usually yellowish eyes in usually weakly developed facial discs, and hooked and cered bills surrounded by facial bristles; body feathering soft and downy in defined tracts; no under downs; aftershafts vestigial; uropygial gland well developed, naked. Feet taloned and anisodactylous; tarsi feathered, outer toe reversible, mid toe longer than inner, with smooth claw; hypotarsus with single deep furrow. Sexes similar, females usually larger. Wings broadly rounded with remiges frayed all round; 10 emarginate primaries plus remicle moulting in descending or serial sequence, and 12–18 diastataxic secondaries moulting at three foci; tail rounded: 12 (rarely 10) rectrices moulting erratically in somewhat centripetal sequence. Nares holorhinal and impervious, nasal septum imperforate; schizognathous (-desmognathous) palate, with small discrete vomer, palatines curved and posteriorly expanded, leaving swollen and pneumatic maxillaries and appressed lachrymals well exposed; basipterygoid processes developed, functional; skull bulbous, with huge orbits separated by thinseptum; cervical vertebrae 14, the neck flexible and able to turn through about 270º; sternum deeply two-notched on each side, only small spina externa present, furcula expanded at articulation with coracoids, without hypocleideum. Musculus expansor secundariorum and biceps slip absent, M. tensor patagium brevis with wristward slip; pelvic muscle formula A or AD, no M. ambiens; deep plantar tendons Type I. Carotid arteries paired. Syrinx bronchial with one pair of intrinsic muscles attached to rings 1–10. Eyes very large, tubular, closed by both lids; ears large, often asymmetric, with little covering flap; tongue fleshy; no crop; caeca large, dilated. Diploid karyotype of 78–82 chromosomes, with 6–7 pairs of macrochromosomes.


General References

Amadon, D. & Bull, J. 1988. Hawks and owls of the world. Proceedings of the Western Foundation of Vertebrate Zoology 3: 295-357

American Ornithologists' Union. 1983. Check-list of North American Birds. 6th Edn American Ornithologists' Union xxix 877 pp.

Beddard, F.E. 1888. On the classification of the Striges. Ibis 30: 335-344

Beddard, F.E. 1890. On Photodilus badius, with remarks on its systematic position. Ibis 32: 293-304

Bock, W.J. & McEvey, A. 1969. The radius and relationship of owls. Wilson Bulletin 81: 55-68

Burton, J.A. (ed.) 1973. Owls of the World. Their evolution, structure and ecology. London : Peter Lowe (Eurobook Ltd) 216 pp.

Christidis, L. 1990. Chordata 3B. Aves. Animal Cytogenetics 4. Berlin : Gebrüder Borntraeger 116 pp.

Clark, R.J., Smith, D.G. & Kelso, L.H. 1978. Working Bibliography of Owls of the World, with summaries of current taxonomy and distributional status. Washington, D.C. : Raptor Information Center, National Wildlife Federation Scientific/Technical Series Vol. 1 319 pp.

Condon, H.T. 1975. Checklist of the Birds of Australia. Part 1 Non-Passerines. Melbourne : Royal Australasian Ornithologists Union xx 311 pp.

Cramp, S. (ed.) 1985. Handbook of the Birds of Europe, the Middle East and North Africa. The Birds of the Western Palaearctic. Oxford : Oxford University Press Vol. 4 960 pp. 98 pls.

Eck, S. & Busse, H. 1973. Eulen Die rezenten und fossilen Formen Aves, Strigidae. Wittenberg, Lutherstadt : A. Ziemsen (Die Neue Brehm-Bücherei). 196 pp.

Feduccia, A. & Ferree, C.E. 1978. Morphology of the bony stapes (columella) in owls: evolutionary implications. Proceedings of the Biological Society of Washington 91: 431-438

Flieg, G.M. 1971. Tytonidae x Strigidae cross produces fertile eggs. Auk 88: 178

Ford, J. 1986. Avian hybridization and allopatry in the region of the Einasleigh uplands and Burdekin-Lynd divide, north-eastern Queensland. The Emu 86: 87-110

Glenny, F.H. 1943. A systematic study of the main arteries in the region of the heart. Aves X. Strigiformes, part 1. Transactions of the Royal Canadian Institute 24: 233-239

Hartert, E. 1921. Die Vögel der paläarktischen Fauna. Systematische Übersicht der in Europa, Nord-Asien und der Mittelmeerregion vorkommenden Vögel. Berlin : R. Friedländer & Sohn Bd Vol. 2 xxiv 833-1764 pp., 135-256 pls. [published between 1912–1921]

Kaup, J.J. 1859. Monograph of the Strigidae. Transactions of the Zoological Society of London 4: 201-260

Marshall, J.T. Jr 1966. Relationships of certain owls around the Pacific. Natural History Bulletin of the Siam Society 21: 235-242

Mathews, G.M. 1910. On some necessary alterations in the nomenclature of birds. Novitates Zoologicae 17: 492-503

Mathews, G.M. 1916. The Birds of Australia. London : Witherby & Co. Vol. 5 pts 2-4 pp. 153-440 pls 245-274. [Date published May 1916: publication dated as 1915–1916]

Mayr, E. & Amadon, D. 1951. A classification of recent birds. American Museum Novitates 1496: 1-42

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

Mees, G.F. 1982. Review of Nocturnal Birds of Australia by R. Schodde and I.J. Mason. The Emu 82: 182-184

Miller, A.H. 1965. The syringeal structure of the Asiatic owl Phodilus. Condor 67: 536-538

Norberg, R.A. 1977. Occurrence and independent evolution of bilateral ear asymmetry in owls and implications on owl taxonomy. Philosophical Transactions of the Royal Society of London B 280: 375-408

Olsen, P. & Stokes, T. 1988. State of knowledge of the Christmas Island Hawk-Owl Ninox squamipila natalis. pp. 411-414 in Meyburg, B.-U. & Chancellor, R.D. (eds). Raptors in the Modern World. Berlin : World Working Group on Birds of Prey and Owls, ICBP 611 pp.

Peters, J.L. 1940. Check-list of Birds of the World. Cambridge : Harvard University Press Vol. 4 xii 291 pp.

Pycraft, W.P. 1898. A contribution towards our knowledge of the morphology of the owls. Part I. Pterylography. Transactions of the Linnean Society of London 2 7: 223-275

Pycraft, W.P. 1903. A contribution towards our knowledge of the morphology of the owls. Part II. Osteology. Transactions of the Linnean Society of London 2nd Series Zoology 9(1): 1-46

Pycraft, W.P. 1903a. On the pterylography of Photodilus. Ibis 45: 36-48

Schodde, R. & Mason, I.J. 1981. Nocturnal Birds of Australia. Illustrated by Jeremy Boot. Melbourne : Lansdowne Edns 136 pp. 22 pls. [publication dated as 1980]

Sharpe, R.B. 1875. Catalogue of the Birds in the British Museum. Catalogue of the Striges, or Nocturnal Birds of Prey. London : British Museum Vol. 2 xi 325 pp. XIV pls.

Sibley, C.G., Ahlquist, J.E. & Monroe, B.L., Jr 1988. A classification of living birds of the world based on DNA-DNA hybridization studies. Auk 105: 409-423

Sibley, C.G. & Ahlquist, J.E. 1990. Phylogeny and Classification of Birds. A Study in Molecular Evolution. New Haven : Yale University Press xxiii 976 pp.

Sibley, C.G. & Monroe, B.L., Jr 1990. Distribution and Taxonomy of Birds of the World. New Haven : Yale University Press xxiv 1111 pp.

Stresemann, E. & Stresemann, V. 1966. Die Mauser der Vögel. Journal of Ornithology 107(Sonderheft): i-viii, 1-448

Vaurie, C. 1965. The Birds of the Palaearctic Fauna A systematic reference. Non-Passeriformes. London : H.F. & G. Witherby xx 763 pp.

Verheyen, R. 1956. Les Striges, les Trogones et les Caprimulgi dans la systématique moderne. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique 32(3): 1-31

Wetmore, A. 1960. A classification for the birds of the world. Smithsonian Miscellaneous Collections 139(11): 1-37

White, C.M.N. & Bruce, M.D. 1986. The Birds of Wallacea (Sulawesi, the Moluccas & Lesser Sunda Islands, Indonesia). An annotated check-list. B.O.U. Check-list No. 7. London : British Ornithologists' Union 524 pp.

Wolters, H.E. 1975–1982. Die Vogelarten der Erde. Eine systematische Liste mit Verbreitungsangaben sowie deutschen und englischen Namen. Hamburg : Paul Parey xx 745 pp.


History of changes

Note that this list may be incomplete for dates prior to September 2013.
Published As part of group Action Date Action Type Compiler(s)
10-Nov-2020 AVES 10-Nov-2020 MODIFIED
26-Nov-2015 STRIGIDAE 04-Nov-2020 MODIFIED
12-Feb-2010 (import)