79 AUSTRALIAN FIELD ORNITHOLOGY 2004, 21 , 79- 80 An Australian Gymnorhina tibicen x Pied nigrogularis Hybrid in the Tanami Desert, Northern Territory

D.B. DONAT0 1 and ROGER T POTTS2

1 39 Allwright Street, Darwin, Northern Territory 0810 2 C/- Adelaide River Post Office, Adelaide River, Northern Territory 0846

Summary

An Gymnorhina tibicen x Cracticus nigrogularis hybrid observed in the Tanami Desert, Northern Territory, is described. The presence of an isolated Magpie population at a human-modified site surrounded by unsuitable habitat is suggested as the reason for the hybridisation.

Introduction Hybridisation is rarely reported among Australian and then usually only amongst closely related congeners such as quail-thrushes [Chestnut-breasted Cinclosoma castaneothorax and Chestnut C. castanotus Quail-thrushes, and Chestnut-breasted and Cinnamon C. cinnamomeum Quail-thrushes: Ford (1974a, 1976, 1983) cited in Higgins & Peter (2002)] at the zone of contact, and interspecific hybridisation is also rare amongst the closely related Noisy Manorina melanocephala and Yellow-throated M. flavigula Miners (Higgins et al. 2001). Hybridisation between extensively sympatric species is almost never recorded although Tarr (1981) reported hybridisation amongst White-browed Artamus superciliosus and Masked A. personatus . There are apparently no previously published reports of hybridisation between Cracticus spp. and the Australian Magpie Gymnorhina tibicen.

Observation and description of hybrid On 12 May 2001 an apparent hybrid Australian Magpie G. tibicen x Pied Butcherbird Cracticus nigrogularis was observed at 19°59'S, l29°32'E in the Tanami Desert, Northern Territory. The was observed feeding on the ground with two Australian , an adult male and a subadult male, investigating recently disturbed windrows from road grading. A description of the hybrid is as follows: the head, throat, breast, back, primaries, undertail-coverts and subterminal tail-band were black; the nape, belly, rump, wing-coverts, lower back, rump, vent and terminal tail-band were white; the mantle was uniform silver-grey; the underwings were white with silver-grey tips to the primaries; the bill was silver-grey as in the Magpie and slightly shorter. The general appearance of the hybrid was of a slightly smaller and predominantly whitish Magpie. It was strong-legged with a shorter gait than the Magpie and an awkward jerky walk. While foraging on the ground with the two Magpies, it also hopped like the Butcherbird. The hybrid was not heard to call. DONATO & POTTS: AUSTRALIAN 80 Australian Magpie x Pied Butcherbird Hybrid FIELD ORNITHOLOGY

Discussion The Pied Butcherbird is common in the area (Gibson 1986) and a breeding resident (RP pers. obs.). The Magpie is rare in the Tanami region (Blakers et al.1980, Barrett et al. 2003), occurring only at peripheral localities of the Tanami Desert such as Mt Doreen, Yuendumu and Anningie Station (Gibson 1986), and in the Tan ami Desert it is only known from the vicinity of a mine site (RP pers. obs.). Magpies at thi~ location have benefited from frequent fires and windrows from road grading, which have provided habitat for ground foraging. The two Magpies and the hybrid were observed from 9 July 2000 to December 2001 within an area of 40 km2 . The Magpies had made temporary use of habitat modified by humans and were isolated from other Magpie populations by inhospitable habitat that minimised the influx of other Magpies. The consequently restricted mate choice (Ford 1987) may be the reason for this hybridisation, although this is unlikely for another apparent Pied Butcherbird x Australian Magpie hybrid reported in the vicinity of Brisbane, Queensland, where both these species are common (J. Hughes pers. comm.).

References Barrett, G., Silcocks, A., Barry, S., Cunningham, R. & Poulter, R. (2003), The New Atlas of A ustralian , Royal Australasian Ornithologists Union, Melbourne. Blakers, M., Davies, S.J.J.F. & Reilly, P.N. (1984), The Atlas of A ustralian Birds, Melbourne University Press, Melbourne. Ford, J. (1987) 'Hybrid zones in Australian birds', Emu 87, 158- 178. Gibson, D.F. (1986), A Biological Swvey of the Tanami Desert in the Northern Te1Tit01y, Technical Report 30, Conservation Commission Northern Territory, Alice Springs, N.T. Higgins, P.J . & Peter, J.M. (Eds) (2002), Handbook of Australian, New Zealand and Antarctic Birds, vol 6, Oxford University Press, Melbourne. Higgins, P.J., Peter, J.M. & Steele, WK. (Eds) (2001), Handbook ofAu stralian, New Zealand and A ntarctic Birds, vol. 5, Oxford University Press, Melbourne, Tarr, J.N.S. (1981), 'An apparent nesting by a hybrid ', Australian Birds 15, 76. Received 21 October 2002 •