AUSTRALIAN 110 BIRD WATCHER

AUSTRALIAN BIRD WATCHER 1995, 16, 110-114

First Sighting of the Elegant Imperial-Pigeon Ducula concinna in Australia

by A. JO WRIGHT1, ROGER JAENSCH2, JOHN WOINARSKP and PETER SOULOS3

1P.O. Box 233, Nightcliff, N.T. 0810 2Wildlife Research Unit, Conservation Commission of the Northern Territory, P.O. Box 496, Palmerston, N.T. 0831 3Clematis Street, Nightcliff, N.T. 0810

Introduction The Elegant Imperial-Pigeon Ducula concinna inhabits the smaller islands and islets in Wallacea from the Aru Islands and those off the Bomberai Peninsula (South Vogelkop region) of Irian Jaya, through to those off the Sulawesi coast (Goodwin 1970, Sibley & Monroe 1990). Localities closest to Darwin (N.T., Australia) that certainly support this species include Pulau Teun 620 km to the north (Goodwin 1970), and Seflllata c. 510 km to the north (Sibley & Monroe 1990). The bird is apparently found only on small islands throughout its range; the Aru Islands located 715 km to the north­ east of Darwin are the largest islands in its range. It is not recorded as a migrating species. We have no current information on its status. Goodwin (1970) quoted Meise (1930) that it was usually found in large flocks on Kalao Tua, where it was abundant.

The sighting In 1991 Soulos, a resident of Clematis Street in the northern Darwin suburb of Nightcliff, heard an unusual bird call in his garden during the middle of the day which he thought may have been the call of a crow. Many months after he noted the original call, a friend, Nigel Gray of Oleander Street, invited him to view the 'crow' which was roosting in a tree in Gray's garden some 100m away. What they saw was a pigeon unlike any they had seen before. Soulos, being a pigeon-breeder, was keen to identify the species and, after confirming that it was not described in Schodde & Tidemann (1986), he contacted a number of people whom he thought may have been able to help. Over many months contacts included prominent aviculturists who had never heard of a bird of such description being held in captivity in Darwin, and long-term Darwin residents who had likewise never heard nor seen a bird that fitted the description offered. Soulos called staff of the Conservation Commission of the Northern Territory (CCNT) at the Territory Wildlife Park, who were interested but unsuccessful in their attempts to view the bird. The description of the bird given to CCNT staff was of a large pigeon with pale body and green wings, and an apparent 'knob' on its upper mandible. A preliminary diagnosis from that information was of a Black-knobbed (or Spice) Imperial-Pigeon Ducula myristicivora. Soulos developed an extensive knowledge of the unidentified bird's habits, including the places it roosted at different times of the day, its preening patterns and a variety of calls, and observed it feeding on seeds of the Carpentaria Palm Carpentaria acuminata in his neighbour's yard. By May 1994 it was about three years since he first heard the bird. He recalled that in the past it had disappeared for long periods before returning to resume its haunts, always in a rather restricted territory, and where VOL. 16 (3) SEPTEMBER 1995 Elegant Imperial-Pigeon in Australia 111 it remained for extended periods. It had always been alone when seen. Although no dates are recorded, Soulos is adamant that the bird was seen in Nightcliff in the dry season. Its identity, however, remained elusive. On 18 September 1993, Wright returned home to Frangipanni Street in Nightcliff after one month away, and within hours heard a new bird call in the neighbourhood. Opposite his home are two large Banyan Figs spanning three entire house-block frontages, magnificent specimens of Ficus virens var. virens. One of these trees is huge and dense, the other a younger tree of lesser proportions and more open canopy, where many local and migratory birds roost. The call was a striking rrhaaahw, loud and resonant, usually repeated after a delay of 10 seconds or so, and always emitted from the more open of the two trees. It was so distinctive that Wright's 18-month-old son quickly added it to his repertoire, along with his replies to Brahminy Kites Haliastur indus which nest in the larger Banyan. The call was usually heard a half dozen or more times at first light between 0600 and 0630 h, and then again in the evening around 1745-1830 h. Typically through the day there was an occasional single call, although on one occasion a Whistling Kite H. sphenurus gliding low overhead provoked three calls in succession. A second distinctive call, low-pitched and quite penetrating, and best represented by due, was heard throughout the day when the bird was present. Attempts to sight the bird were fruitless for many weeks. Despite hearing the bird almost every day, Wright was unable to catch a glimpse of it. A neighbour reported subsequently that she had heard the bird for perhaps a few weeks earlier, but similarly it had remained out of her sight. The calls were absent for a week or so in early October, but then were given at their original location on a daily basis for a further three weeks. A good view of the particular tree was had from the balcony of Wright's elevated house, which was 40 m from the tree's base and less than 25 m from the edge of its canopy, but in spite of this the bird remained elusive. On 22 October 1993, at 1750 h, he caught sight of what initially was thought to be a large Pied Imperial-Pigeon Ducula bicolor. While still silhouetted, the bird raised its head, ruffled the feathers at the back of its neck, opened its bill widely and emitted a loud rrhaaahw. It moved off on that occasion but the following morning at 0545 h in dull first light it was seen sitting in the open on the powerlines not 10 m from the balcony. It retreated to the position at the top of the open Banyan where it had been observed the previous day, and was to be seen within a 3 m radius of the same position on a twice-daily basis for the following week. Wright was able to study it through 7 x 50 binoculars from 40 m, make a sound-recording of the call, and obtain several colour photographs over the next few days, all at times of fairly low light. The following is adapted from Wright's original field notes: The bird is slightly larger than the Torresian [Pied] Imperial-Pigeon. The head, throat and breast are pale grey with a hint of a fawn wash, eye is orange, bill black with a small cere on the upper mandible and a ring of white feathers around the base; wings, back and tail are dark grey-black, the long tail is centrally notched; strong bare legs are bright pink-red. In flight the underwing is entirely dark grey, and the wingbeats are slower and more deliberate than the Torresian pigeon. The bird looked to be without injury. The call was often emitted in response to the close approach of Pied Imperial­ Pigeons, which are numerous in the area at the time of year and very active at dawn and dusk, and which at that time were rather preoccupied with mating behaviour. The particular Banyan was heavily fruiting with small green fruit, which attracts flocks of up to 50 Rainbow Lorikeets Trichoglossus haematodus rubritorquis and up to a dozen or so Pied Imperial-Pigeons at the peak viewing times of dawn and dusk, all feeding rather noisily. In contrast, the bird was indifferent to the surrounding feasting. It climbed along branches quite inconspicuously, occasionally hopping to another perch, AUSTRALIAN 112 WRIGHT, JAENSCH, WOINARSKI & SOULOS BIRD WATCHER and on several occasions was seen to peck at fruit but never observed to eat them, and was mostly inactive. It disappeared from view around 0630 h, flying at well below tree-top height to nearby trees, and thence out of view. Its distinctive call could occasionally be heard from elsewhere in the neighbourhood, but in the main it called repetitively only at its 'home perch'.

Diagnosis On 29 October 1993 at 0600 h Woinarski and Jaensch were able to join Wright on the balcony armed with a collection of regional bird guides to assist in identification, and succeeded in viewing the bird around 0700 h. It appeared suddenly at the usual open perch at the top of the Banyan tree, and its size was slightly larger than a Pied Imperial-Pigeon. Additional observations in the brighter light, from Jaensch's field notes, included: a fine yellow ring around the bright orange iris, an iridescent green visible on the shoulders, black bill which appeared laterally broad at the base, a dark, dull chestnut vent, and black claws. The back, rump, upperwing coverts and secondaries were dark grey with green, blue and/or bronze iridescence that was bright at some angles to the light. There was possibly a brighter blue sheen on the rump. Upper side of primaries and tail were similar to the back but with Jess iridescence, often appearing black. The description and calls match closely those of the Elegant Imperial-Pigeon described in Goodwin (1970, p. 396, where it is referred to as Blue-tailed Imperial Pigeon) and Beehler et al. (1986) . The small cere is not described in either published account, but in all other respects it matches closely. Similar species are the White­ eyed Imperial-Pigeon Ducula perspicillata (of the larger islands between Sulawesi and New Guinea), which is distinguished from this bird by a darker head, paler vent and dark brown irides; and the Black-knobbed Imperial-Pigeon (of far north-western New Guinea and adjacent islands), which when compared with this bird has more pink on the underparts, paler underwings, and brown irides. Juveniles of the latter may lack the enlarged cere. Goodwin (1970), referring to the regular habits of the Green Imperial-Pigeon D. aenea (which forms a 'superspecies' with D. perspicillata and D. concinna), described how it keeps to regular flight paths to and from roosting sites in spite of frequent hunting by humans. Further enquiries with local pet-suppliers and a prominent aviculturist confirmed that large fruit-pigeons are rarely if ever stocked in Darwin and there is little local interest in keeping them. No imperial-pigeons are known to have been kept or lost in the Darwin area. We conclude, therefore, that the unusual bird seen in Nightcliff was a genuine vagrant of the Elegant Imperial-Pigeon, which as far as we are aware is the first record of this species for Australia. The bird may have travelled to Darwin with migrating Pied Imperial-Pigeons which arrive each year at the end of August. The record has been accepted by the RAOU Records Appraisal Committee on the basis of this paper, a published photograph (J. Estbergs in Andrew & Eades 1993, p. 15), and additional field notes with two colour transparencies obtained by an RAC member (submission no. 181, R.M. Patterson in litt.). The supplementary field notes describe the iridescence on the upperwings as 'turquoise green' and the uppertail coverts as 'iridescent blue'. The RAC verdict also comments that 'The original observer had noted a "knob" on the bill, but this may have been no more than the slight swelling at the cere - the photos and subsequent descriptions deny the presence of a true knob' (copy per R.M. Patterson). The RAC further concluded that the evidence is sufficient to rule out the Island Imperial-Pigeon D. pistrinaria and Pacific Imperial-Pigeon D. pacifica as well as the White-eyed and Black-knobbed Imperial-Pigeons. Soulos has been able to confirm that the bird has the same appearance as the one VOL. 16 (3) SEPTEMBER 1995 Elegant Imperial-Pigeon in Australia 113 he had seen in his garden on each of the two previous wet seasons. It has been behaving in the same manner and in his opinion it is the same bird seen during the past two years. Further observations A unique situation arose in that a single bird of such great interest to a large number of people was rather conveniently resident in a city of 80 000 people. An attachment to the bird developed among those who came to recognise it, and an expanding network of informants developed. It was seen by a number of interstate bird-watchers. The bird moved on for a week or so before returning to Nightcliff, and on this occasion took to roosting in an African Mahogany Khaya senegalensis about 50 m from the previously favoured Banyan. It was regularly seen in its usual perch for periods of up to 30 minutes at either end of the day. Reports came in of its other movements including other African Mahoganies it visited during the day in Nightcliff, and a Milkwood Alstonia actinophylla in Oleander Street in Nightcliff, where it was regularly seen between 0715 and 0745 h for some months. The behaviour of the bird began to change around the end of October, in that it called much less frequently. The Pied Imperial-Pigeons had all commenced nest­ building, and were much more territorial themselves. On one occasion at 1530 h on 11 November 1993 the Elegant Imperial-Pigeon was seen to be moving twigs in apparent nest-building behaviour, constructing a small platform in a thicket of leaves in the most protected portion of the canopy of the same open Banyan. This behaviour was witnessed by a large tour group of bird-watchers, but was never seen repeated. In mid November the bird became more difficult to see, mainly as the Pied Imperial­ Pigeons began to chase it away whenever it adopted the usual prominent perch in the crown of the open Banyan. It was, however, now observed to be eating a number of figs from the same tree when they were in a pale green stage, and also small fruits from a variety of trees around the local gardens. The bird's appearance remained unchanged through the months of observation; the small cere had the same prominence as when first sighted. It called infrequently once the wet season arrived, and that had not changed at the end of May 1994. It displayed a peculiar habit of calling after thunderstorms or rain during the wet season, no matter what the time, including any time overnight. The last flock of Pied Imperial­ Pigeons seen in circuit flight was noted on 2 May 1994, and their numbers were subsequently much reduced. The Elegant Imperial-Pigeon remained, and over the months of April and May was roosting in two other gardens in Nightcliff, one address in Verbena Street and the other in Bougainvilia Street. Two Elegant Imperial-Pigeons were reportedly present in May, and one was present until November 1994 (Andrew & Eades 1994, Eades 1994). Wright viewed the pigeon regularly in Frangipanni Street through the latter half of 1994, but noted that it was neither seen nor heard in Nightcliff after mid November. The last confirmed sighting was in Leanyer, 6 km from Nightcliff. During the second and third weeks of December 1994 it was spending daytimes feeding and calling in a garden on the edge of the Leanyer Swamp (T. O'Brien pers. comm.), which it had also visited during the previous wet season. We have no more recently reported sightings. It is very likely that at least one vagrant individual is now a permanent resident. One may only speculate as to the exact circumstances and timing of its arrival, and be alert to the possibility of arrivals of other neighbouring species. Acknowledgements We thank Bob Patterson for communicating the RAC assessment of the record with additional information, and John Cox for comments on the manuscript. Thanks are also due to the various local and interstate bird-watchers who contributed information, and to the local media for publicising the sightings and helping to raise the community's level of interest in birds. AUSTRALIAN 114 WRIGHT, JAENSCH, WOINARSKI & SOULOS BIRD WATCHER

References Andrew, D.G. & Eades, D.W. (1993), 'Twitchers' Comer', Wingspan 12, 15. -- & -- (1994), 'Twitchers' Comer', Wingspan 14, 3. Beehler, B.M., Pratt, T.K. & Zimmerman, D. A. (1986), Birds of New Guinea, Princeton University Press, Princeton. Eades, D.W. (1994) , 'Twitchers' Comer', Wingspan 16, 3. Goodwin, D. (1970), Pigeons and Doves of the World, 2nd edn, Trustees of the British Museum (Natural History), London. Schodde, R. & Tidemann, S.C,. (Eds) (1986), Reader's Digest Complete Book of Australian Birds, 2nd edn, Reader's Digest Services, Sydney. Sibley, C.G. & Monroe, B.L. (1990), Distribution and Taxonomy of Birds of the World, Yale University Press, New Haven. Received 3 June 1994, revised 8 May 1995 •