Distribution, Status and Habitat of the Red Goshawk Erythrotriorchis Radiatus in Queensland
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Corella, 2010, 35(1): 3-10 Distribution, status and habitat of the Red Goshawk Erythrotriorchis radiatus in Queensland G. V. Czechura1, R. G. Hobson2 and D. A. Stewart3 1Queensland Museum, P.O. Box 3300, South Brisbane, Queensland 4101 (E-mail: [email protected]) 2Department of Environment and Resource Management, P.O. Box 731, Toowoomba, Queensland 4350. 3Department of Environment and Resource Management, P.O. Box 64, Bellbowrie, Queensland 4070. Received: 21 July 2009 Field surveys of the Red Goshawk Erythrotriorchis radiatus were conducted in south-east Queensland in 1995 and again in 2001; in northern Queensland in 1999; and on Cape York Peninsula in 2000. In south-eastern Queensland, Red Goshawks were found at 25 localities in 1995, representing at least 10–12 (possibly up to 16) resident pairs; breeding was suspected but not confi rmed at one site. In 2001, records representing 15–16 pairs were obtained, with breeding confi rmed at one site, reported in prior years at a second site, and confi rmed at another site after the survey in 2003. In northern Queensland, Red Goshawks were found or reported at 23 localities in the eastern parts, representing 5–8 pairs (one with a fl edgling), and three nests (one active) were found. On Cape York Peninsula, Red Goshawks were found at 20 localities. The records included nine pairs and three active nests; most of these (including the active nests) were in central and eastern parts of the Peninsula. Red Goshawks inhabit biodiverse, extensive, multi-species mosaics of mainly eucalypt-dominated open forests and woodlands, in permanently watered, varied terrain, and nest high (>20 m) in emergent trees with an open limb and canopy structure. The Queensland population is estimated at up to 135–140 pairs (10–30 in the south-east, 30–35 in the north-east, and 60–70 on Cape York Peninsula). Identifi ed key threats include habitat clearance, logging of nesting habitat, and loss or degradation of freshwater wetlands. Recommendations for the species’ conservation and management include further survey and monitoring, and ecological research. INTRODUCTION In this paper, we report the results of surveys aimed at determining the Red Goshawk’s distribution, population status The endemic Red Goshawk Erythrotriorchis radiatus is and habitat use in south-eastern and northern Queensland. listed as vulnerable nationally and in the Northern Territory, rare in Western Australia, endangered in Queensland (Qld), STUDY AREAS AND METHODS and critically endangered in New South Wales (NSW), under relevant federal and state legislation. It formerly occurred south Much of this study relied on prior knowledge of the Red to Sydney, but has all but disappeared from that state, and was Goshawk’s broad ecology and occurrence in Queensland (Debus and Czechura 1988; Debus et al. 1993a, b; Marchant historically widespread and fairly frequently encountered in and Higgins 1993), and consideration of prevailing topography coastal eastern Queensland (e.g. Debus and Czechura 1988; and vegetation. Earlier (private) surveys by GVC and past Debus 1993; Debus et al. 1993a, b; Marchant and Higgins reliable sightings by credible observers were used to identify 1993). It forms an Australasian endemic genus with only one priority locations for survey: primarily extensive forested areas close relative in New Guinea, the Chestnut-shouldered Goshawk with permanent water. E. buergersi, and part of an ‘old endemic’ raptor assemblage not allied to Accipiter (e.g. Debus 1998). An initial fi eld survey was conducted by GVC (with supporting information from RGH) in south-east Queensland The Red Goshawk’s ecological requirements in eastern primarily during January–August 1995, supplemented by Australia are poorly known compared with the information other Red Goshawk sightings obtained between September collected on the species in the Northern Territory and Kimberley 1994 and February 1996. Surveys were conducted across the region of Western Australia (Aumann and Baker-Gabb 1991; area bounded by Mackay in the north (Central Mackay Coast Marchant and Higgins 1993). Previous reviews of the bird’s Bioregion), Dalby in the west (Brigalow Belt South Bioregion) ecology in Queensland describe aspects of its forest or woodland and the New South Wales border in the south (South Eastern habitat in general terms (Debus and Czechura 1988; Debus et al. Queensland Bioregion; Thackway and Creswell 1995) – see 1993b; Marchant and Higgins 1993). Findings from our recent Figure 1. Priority was given to regions where human impact study of the Red Goshawk’s breeding biology (including nest- was great (to identify remnant Goshawk populations or site characteristics), diet and foraging behaviour in Queensland important habitat), or where local conditions and topography are reported elsewhere (Czechura et al. 2009). Desktop studies provided vantage points. Selected sites (n = 23 locations) and preliminary habitat modelling in Queensland have also been were then visited for 2–3 days each, with observers stationed conducted, for the South Eastern Queensland Bioregion (Ward at observation points. One suspected nesting area, occupied 2000; Stewart 2006). by a pair, was visited regularly during the breeding season 3 4 G.V. Czechura, R.G. Hobson and D.A. Stewart: Distribution, status and habitat of the Red Goshawk in Qld Corella 35(1) • Pajinka • Weipa • Coen CAPE YORK PENINSULA • Cooktown • Mossman • Cairns • Atherton Burketown • Normanton • WET TROPICS GULF PLAINS Georgetown EINASLEIGH • UPLANDS • Lawn Hill NP • Einasleigh • Ingham Townsville • • Ayr Bowen • Charters Towers• MT ISA INLIER • Proserpine • Mount Isa • Cloncurry • Hughenden CENTRAL MACKAY COAST • Mackay DESERT UPLANDS MITCHELL GRASS DOWNS • Winton • Rockhampton • Longreach • Emerald • Gladstone BRIGALOW BELT • Bundaberg • Carnarvon Gorge NP Marybrough • • Birdsville SOUTH EASTERN • Gympie • Charleville QUEENSLAND CHANNEL COUNTRY • Roma MULGA LANDS BRISBANE Dalby • • Toowoomba • Warwick Gold Coast • • NEW ENGLAND TABLELAND Figure 1. Red Goshawk records in Queensland, incorporating the survey results of this study. Source: Qld DERM Red Goshawk conservation management profi le (prepared by S. Ryan, 2006) overlain on the Bioregional Map of Queensland V0001 (courtesy of Qld DERM). (September 1995–February 1996). Selected volunteer observers via: (i) a search by RGH in February–June (n = 14 sites), were also recruited to the project, for their additional sightings and (ii) a volunteer-based survey co-ordinated by DAS (n = during the survey period. 12 locations, 124 volunteer-days). Volunteers either stayed at vantage points, scanning for Red Goshawks, or drove along The fi eld sites surveyed in south-east Queensland in 1995 roads and tracks through suitable habitat, for at least one day were re-surveyed in 2001, with the exception that the region per month through the year, and the survey effort included nest was re-defi ned as the South Eastern Queensland Bioregion. searches in likely habitat (n = 24 volunteer-days). A desktop Hence, some of the most northern and inland locations in analysis of Red Goshawk records in the bioregion was also the 1995 survey (Central Mackay Coast and Brigalow Belt conducted by DAS, using the Queensland Wildnet (fauna atlas) bioregions) were excluded. Field surveys for Red Goshawks database, the results of the 1995 survey, and records from the (Border Ranges north to Gladstone and Carnarvon Gorge, 2001 survey. After vetting the records, all reliable historical inland to the Great Dividing Range) were conducted in 2001 and recent records were mapped (Figure 1). March 2011 G.V. Czechura, R.G. Hobson and D.A. Stewart: Distribution, status and habitat of the Red Goshawk in Qld 5 Field surveys for Red Goshawks were conducted in by a combination of these methods. Observations were made northern Queensland (Townsville north almost to Coen and with 10 × 40 or 10 × 42 binoculars, and a 25× or a 20–60× west to Burketown and Lawn Hill National Park) in August– zoom telescope. At all surveys sites, a record was kept of avian December 1999 by GVC and RGH, and on Cape York Peninsula diversity (i.e. potential prey populations) in the form of species (Georgetown–Mt Surprise north to Pajinka) in September lists based on sight records and subjective assessments of 2000–January 2001 by GVC. Priority was given to areas where abundance and distribution. Habitat classifi cations followed the sightings had been reported previously, and where vegetation structural categories of Specht (1970) and regional ecosystems structure and/or fl oristics were similar to where the species had of Sattler and Williams (1999). As individual Red Goshawks been found in southern Queensland in 1995. In 1999, surveys are mobile and wide-ranging (Marchant and Higgins 1993), we focused on the Einasleigh Uplands Bioregion, owing to the consider habitat at the level of vegetation structural type and proposed expansion of sugar plantations and land-clearing for dominant tree species. grazing, and on coastal parts of the Wet Tropics Bioregion where large areas of forest and woodland still extended onto the coastal Red Goshawks are diffi cult to identify, and other reddish- lowlands from the ranges. Surveys were guided by reliable brown raptors (notably the Square-tailed Kite Lophoictinia sightings from credible observers, existing information and the isura, female Swamp Harrier Circus approximans and rufous presence of apparently suitable habitat, and by discussions with Brown Falcons Falco berigora) are often misidentifi ed