Family AEGOTHELIDAE

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Introduction

Aegothelidae (owlet-nightjars) comprise seven or eight species in one genus; one species occurs in Australia. The family is represented in the Australian fossil record in the Pleistocene of Queensland, Victoria and Western Australia, and in the Miocene of New South Wales by Quipollornis koniberi Rich & McEvey, 1977 from the Warrumbungle Mountains. The family is restricted today to Australia, New Caledonia, the Moluccas and notably New Guinea, where it is centred with about five or six species.

Owlet-nightjars are nocturnal insectivores that, solitary or in pairs, roost by day in holes in trees or sometimes cliffs, and fly by night with flutter and glide action to catch insects aerially or from surfaces, e.g. the ground. Nests are poorly formed in tree hollows or clefts; eggs are spherical, plain white with sheen, several per clutch; and young are altricial, nidicolous, and covered with dense long whitish down from which they apparently moult directly into a patterned teleoptile plumage. Both sexes share nidificational duties.

Family-group Systematics

This apparently monogeneric family is sometimes considered to be linked integrally with either or both Podargidae (frogmouths) and Caprimulgidae (nightjars), cf. Schodde & Mason (1981); but it is probably not related so closely to either, see Olson et al. (1987) and Sibley et al. (1988). Aegothelidae was treated as a subfamily of Podargidae by Hartert (1892) and Beddard (1898), but since the turn of the century has been separated consistently as a distinct family—see Stresemann (1927–1934); Peters (1940); Mayr & Amadon (1951); Wetmore (1960); Condon (1975); Wolters (1975–1982); Schodde & Mason (loc. cit.); Sibley & Ahlquist (1990); Sibley & Monroe (1990).

Genus-group Systematics

Aegotheles Vigors & Horsfield, 1827—Generic elements of living Aegothelidae have been assessed by Mathews (1918: 51–52), Schodde & Mason (1981: 107) and Olson et al. (1987). There are several groups of species, none of which seem distinct enough to recognise at more than subgeneric level, cf. Olson et al. (loc. cit.). Most distinctive among them is dispecific Papuasian Euaegotheles Mathews, 1918, which nevertheless has the same cranial, nasal and maxillary features as other species of the genus. The latter differ from Euaegotheles, however, in their combination of greyer-toned plumage, reduced supra-orbital tufts, round-tipped rectrices, longer legs (tarsus: wing ratio c. 0.16–0.20), feathered tibio-acrotarsial joint and less expanded palatine shelf, cf. Mathews (loc. cit.); Olson et al. (loc. cit.). The two groups are treated as subgenera here, pending clarification of their relationships.

Species-group Systematics

Aegotheles cristatus (Shaw, 1790)—This polymorphic Australian-centred species poses difficulties both in regional differentiation and in delimitation from its rainforest-inhabiting New Guinean vicariant, A. bennettii Salvadori & d'Albertis, 1875—see Schodde & Mason (1981). For further analysis of mainland Australian populations, see Greenway (1978).

 

Diagnosis

Small, rather thick-set broad-headed birds, patterned in camouflaging greys and russets, with very broad flexible bills, terminal rounded nostrils and long overhanging barbed rictal and facial bristles; body feathering soft, almost downy in defined tracts; no general downs; aftershafts plumed but small; uropygial gland large, naked. Feet delicate, anisodactylous; reticulate scaling on smooth slender tarsi obscure, outer forward toe with five phalanges, and all toes similarly long; hypotarsus with one closed canal. Sexes alike. Wings short and rounded, the trailing edges of remiges frayed: 10 primaries plus remicle moulting in descending sequence, and 12–14 diastataxic secondaries; tail rather long and rounded: 10 rectrices. Nares schizorhinal-holorhinal and impervious, nasal septum extensively perforate; schizognathous palate with vomer fused in a blunt, thickened apex, free from fenestrate maxillo-palatine shelf, reduced maxillaries weak with jugal bar becoming cartilaginous at its articulation with the quadrate; palatine shelf broadly winged and entire, naso-frontal hinge articulate, lachrymals vestigial, and ectethmoids small and free from palatines; basipterygoid processes absent (to rudimentary?); long dentary bone fused with supra-angular in lower jaw; cervical vertebrae 13; sternum with two large fenestrae on each side, only shortly bifid spina externa present, furcula with vestigial hypocleideum. Musculus expansor secundariorum and biceps slip absent, and M. tensoris patagium brevis without wristward slip; pelvic muscle formula AXY, no M. ambiens; deep plantar tendons Type V, fused. Carotid arteries paired(?). Syrinx bronchial, with intrinsic muscles attached to first bronchial rings. Eyes large, tubular, front-facing; tongue vestigial, flap-like; no caeca. Karyotype unknown.

 

General References

Beddard, F.E. 1886. On the syrinx and other points in the anatomy of the Caprimulgidae. Proceedings of the Zoological Society of London 1886: 147-153

Beddard, F.E. 1898. The Structure and Classification of Birds. London : Longmans, Green xx 548 pp.

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

Greenway, J.C. 1978. Type specimens of birds in the American Museum of Natural History. Pt 2. Bulletin of the American Museum of Natural History 161: 1-306

Hartert, E. 1892. Catalogue of the Birds in the British Museum. Catalogue of the Picariae. Coraciae. London : British Museum Vol. 16 xvi 703 pp., xiv pls.

Mathews, G.M. 1918. The Birds of Australia. London : Witherby & Co. Vol. 7 pt 1 pp. 1-112 pls 325-336. [Date published 4 Mar. 1918]

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

Olson, S.L., Balouet, J.C. & Fisher, C.T. 1987. The owlet-nightjar of New Caledonia, Aegotheles savesi, with comments on the systematics of the Aegothelidae. Le Gerfaut 77: 341-352

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

Rand, A.L. & Gilliard, E.T. 1967. Handbook of New Guinea Birds. London : Weidenfeld & Nicolson x 612 pp. 53 pls.

Salvadori, T. 1880. Ornitologia della Papuasia e delle Molucche. Parte Prima. Torino : G.B. Paravia & Co. xii 573 pp.

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]

Schodde, R. in Schodde, R. & Mason, I.J. 1997. Aves (Columbidae to Coraciidae). In, Houston, W.W.K. & Wells, A. (eds). Zoological Catalogue of Australia. Melbourne : CSIRO Publishing, Australia Vol. 37.2 xiii 440 pp.

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.

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

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

Published	As part of group	Action Date	Action Type	Compiler(s)
		12-Feb-2010	(import)