VOL. 17 (5) MARCH 1998 Taking Prey 263

Adult male Red Goshawk, , N.T., September 1988 Plate 33 Photo: S. Debus

Observations of Red Goshawk radiatus Taking Prey and Being Robbed

On 8 November 1996 at 0930 h in Kakadu National Park, N.T. , as we walked in open eucalypt woodland dominated by Poplar Gum Eucalyptus alba var. australasica with a dry grass understorey of Kangaroo Grass Themeda , we flushed Bar-shouldered Doves Geopelia humeralis feeding on the ground in the shade of the trees. As they flew to perch in a nearby eucalypt an adult male Red Goshawk Erythrotriorchis radiatus pursued them at tremendous speed. The Goshawk passed some in mid flight, and approached others which had just perched. Climbing out of its swoop, the Goshawk was upside down as it took a perched Dove. It then righted itself and, with its prey, flew directly to nearby dense vegetation fringing a large river. We followed the Goshawk for c. 500 m upstream, from which direction we could hear a persistent call which we assumed to be that of a Red Goshawk. The adult was found drinking from the river, and it subsequently perched a short distance from us . It was then positively identified as an adult male by its slight appearance, rufous chest and abdomen, and yellow eyes (from Aumann & Baker-Gabb 1991 , Marchant & Higgins 1993, Debus et al. 1993). It then circled about 15 m above us for 15-20 seconds. Its back and upperwings were mottled rufous-brown; the breast and belly were dark rufous with darker vertical streaks, lighter towards the throat; the thighs were unstreaked dark rufous; the legs were yellow and slender with powerful AUSTRALIAN 264 WILKINS & DONATO WATCHER feet; the eyes were yellow and the bill black; underwing linings were dark rufous, with primaries and secondaries almost clean white-grey with no obvious barring; the undertail was grey-brown with no obvious barring. It flew with wings slightly upswept when gliding, on shallow wing-beats with fingered wing tips. When the male Goshawk disappeared, we continued to walk in the direction of the persistent call, soon locating a nearly fledged nestling. The nest was in a tall unidentified live eucalypt c. 25 min height, located on an exposed horizontal branch c. 20m above the ground and c. 80 m from the river. This nest was not recorded by Aumann & Baker-Gabb (1991), nor was it known to Aumann (pers. comm.). The nest tree was c. 600 m from where the Dove was taken by the male Goshawk. A 20x spotting scope was focused on the nestling from a distance of c. 100m. The juvenile was rufous ventrally, although not as rufous as the adult male, and noticeably larger in size. Its back and upperwings were mottled red-brown; the breast and abdomen were rufous with obvious dark vertical streaks; the throat was cinnamon; the thighs were a uniform dark rufous colour; the legs were massive and pale yellow; the bill black and cere grey; the undertail was strongly barred black and grey. The voice was similar to that of Accipiter species, but rather drawn-out and not as rapid. The nestling was identified as a female by its size in comparison with the adult male. The captured Bar-shouldered Dove could not be seen in the nest, and the nestling Goshawk was not observed to eat. We then left the area and returned in the afternoon, observing the nest until nightfall. At c. 20 minutes before dark the adult male Goshawk dropped an unidentified small bird into the nest, quickly departed and perched c. 100m away. The nestling did not feed. Some five minutes after the prey had been deposited, a Whistling sphenurus circled briefly above the nest, swooped down, and took the prey item. The nestling responded by crouching and opening its beak in an aggressive manner. The adult male Goshawk called and flew with reasonable speed toward the nest, but did not pursue the . The Whistling Kite is a well-known pirate of other raptors' food (e.g. Marchant & Higgins 1993), but it is surprising that it could successfully rob such a formidable bird as a Red Goshawk.

References Aumann, T. & Baker-Gabb, D. (1991), The Ecology and Status of the Red Goshawk in Northern , RAOU Report 75. Debus, S.J.S., McAllan, I. A.W. & Mead, D.A. (1993), 'Museum specimens of the Red Goshawk Erythrotriorchis radiatus. I. Annotated list of specimens', Sunbird 23, 5-28. Marchant, S. & Higgins, P.J. (Eds) (1993), Handbook of Australian, New Zealand and Antarctic , vol. 2, Oxford University Press, Melbourne. By P.J. WILKINS' and D.B. DONAT02

1Parks and Wildlife Commission of the Northern Territory, P. 0. Box 1046, Alice Springs, N. T. 0871 211 Cheong Crescent, Millner, N. T. 0810 Received 21 May 1997 •