Red goshawk (Erythriotriorchis radiatus) - critically endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the Red Goshawk Erythrotriorchis radiatus (Latham, 1802) as a CRITICALLY ENDANGERED SPECIES in Part 1 of Schedule 1A of the Act, and as a consequence, to omit reference to the Red Goshawk Erythrotriorchis radiatus (Latham, 1801) from Part 1 of Schedule 1 (Endangered species) of the Act. Listing of Critically Endangered species is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. The Red Goshawk Erythrotriorchis radiatus (Latham, 1802) is a large, reddish-brown hawk with strongly streaked and barred plumage, massive yellow legs and feet, and a slight crest. Males are 50 cm in length, females 60 cm in length, with a wingspan of 111-136 cm. Many other raptors are likely to be misidentified as the Red Goshawk, notably the Square-tailed Kite which is more slender with very long wings and small bill and feet, and the female Swamp Harrier which is more uniform brown dorsally with a white rump.

2. The Red Goshawk occurs in open forest and riparian woodland from the Kimberley in north-western Australia to the subtropical east coast (Marchant & Higgins 1993). In NSW it is restricted to the north-east, mostly on or near the coast. Verified historical records extend south to Sydney. Historically, it bred in the lower Richmond Valley and probably in the Clarence Valley, where an adult male was collected. The range of recent verified records has contracted in the last few decades to northern parts of the North Coast, being confined to the Mann, Clarence, Richmond and Tweed Valleys. This species occurs as a single, sparse population in NSW, with possible movement and genetic interchange across the NSW-Queensland border. There are no currently known nest sites in NSW, so precise locations (with respect to specific threats) cannot be identified. The nearest known recent breeding record was in south-east Queensland near the NSW border in 2003. Of the literature records discussed by Debus (1991) and NSW NPWS (2002), the identifications for the southern and some north-central records are thought to be inaccurate, and the acceptable north-central records date from before 1980 (Debus 1991).

3. The Red Goshawk’s NSW population is now extremely low. There have been very few records of the species during the past two decades, and there are probably fewer than 10 birds currently in NSW (Debus 1991, 1993; Debus et al. 1993a, b). Most of these may be vagrants; however, the species may still breed near the Queensland border. Although raptors are difficult to identify, and the Red Goshawk is secretive and cryptic, the level of confidence in survey records is high because birdwatchers are numerous and very active in the species’ NSW range. False positives (misidentifications of other raptors as Red Goshawk) are more likely than Red Goshawks being mistaken for other species. The total global population is estimated to be 350 pairs, having declined from a historical population estimated to be 440 pairs. Most pairs are currently in tropical northern Australia (Kimberley of Western Australia, Top End of the Northern Territory; northern and eastern Queensland), with 180 pairs in Queensland (Aumann & Baker-Gabb 1991).

4. This species was recorded in three 10-minute grids in far north-eastern NSW during the first national bird atlas in 1977-81, at a low reporting rate (Blakers et al. 1984). There were no records for NSW in the second national bird atlas in 1998-2002 (Barrett  et al. 2003). There were at least 25 records for NSW in 1980-1990, but only six for 1990-2000, and three since 2000. The geographic spread of NSW records has contracted steadily northwards (Debus 1991, 1993; Debus  et al. 1993b). There has been a greater than 90% decline in the species’ index of abundance (atlas and other reporting rates) in three generations (30 years), matched by a  c. 80% decline in extent of occurrence over the same period. As some of the eight sightings in the 1990s and early to mid 2000s are unverified, the decline may be even greater. Extensive searches in riparian and other habitats over three years, including the area where the last known pair was regularly seen (Debus 1992, 1993), failed to find the species. In contrast with these declining records, birdwatching effort has increased in the area since the 1980s ( e.g. the sources used by Debus (1991) have continued and expanded, as judged by the increasing volume of data and number of contributors in the NSW Field Ornithologists Club annual bird reports and in the two national bird atlases).

5. The main historical threat to the Red Goshawk is deforestation, particularly of coastal lowlands, foothills, riparian flats and floodplains (Debus et al. 1993b). Deforestation and other habitat disturbance/degradation processes are still occurring throughout coastal and subcoastal parts of the NSW North Coast Bioregion, associated with continuing development on the coast and hinterland (resort development, urban expansion, rural-residential subdivisions, and road/highway upgrades). The goshawk’s habitat is severely fragmented but the high mobility of the species makes any segregation of the population less likely. Pesticides in the avian food chain may be a threat, as for other bird-eating raptors (Debus  et al. 1993b). DDT was previously a threat but has been banned from use for at least two decades, and its effects appear to have ceased for some bird-eating raptors such as the Peregrine Falcon. ‘Clearing of native vegetation’ is listed as a Key Threatening Process under the NSW  Threatened Species Conservation Act 1995.

6. The Red Goshawk is listed as Endangered in Queensland, and is nationally listed as Vulnerable (Environment Protection and Biodiversity Conservation Act 1999) and subject to the Bonn Convention on migratory species.

7. Red Goshawk Erythrotriorchis radiatus (Latham, 1802) is eligible to be listed as a Critically Endangered species as, in the opinion of the Scientific Committee, it is facing an extremely high risk of extinction in New South Wales in the immediate future as determined in accordance with the following criteria as prescribed by the  Threatened Species Conservation Regulation 2002:

Clause 14

The species has undergone, is observed, estimated, inferred or reasonably suspected to have undergone or is likely to undergo within a time frame appropriate to the life cycle and habitat characteristics of the taxon:

(a) a very large reduction in population size,

based on:

(d) an index of abundance appropriate to the taxon

(e) geographic distribution, and habitat quality or diversity, or genetic diversity

Clause 16

The estimated total number of mature individuals of the species is:

(a) very low,

and:

(d) a projected or continuing decline is observed, estimated or inferred in:

(i) an index of abundance appropriate to the taxon

(ii) geographic distribution, and habitat quality or diversity, or genetic diversity

Clause 17

The total number of mature individuals of the species is observed, estimated or inferred to be:

(a) extremely low

Dr Richard Major
Chairperson
Scientific Committee

Proposed Gazettal date: 31/07/09
Exhibition period: 31/07/09 - 25/09/09

References:

Aumann T, Baker-Gabb DJ (1991) ‘The ecology and status of the Red Goshawk in northern Australia.’ RAOU Report no. 75. (Royal Australasian Ornithologists Union: Melbourne)

Barrett G, Silcocks A, Barry S, Cunningham R, Poulter R (2003) ‘The new atlas of Australian birds.’ (RAOU: Melbourne)

Blakers M, Davies SJJF, Reilly PN (1984) ‘The atlas of Australian birds.’ (Melbourne University Press: Melbourne)

Debus SJS (1991) An annotated list of New South Wales records of the Red Goshawk. Australian Birds 24, 72-89.

Debus SJS (1992) A survey of diurnal raptors in north-east New South Wales, 1987-1990. Australian Birds 25, 67-77.

Debus SJS (1993) The status of the Red Goshawk Erythrotriorchis radiatus in New South Wales. In ‘Australian raptor studies’. (Ed. P. Olsen) pp 182-191. (Australasian Raptor Association, RAOU: Melbourne)

Debus SJS, McAllan IAW, Mead DA (1993a) Museum specimens of the Red Goshawk Erythrotriorchis radiatus. I. Annotated list of specimens.  Sunbird 23, 5-28.

Debus SJS, McAllan IAW, Mead DA (1993b) Museum specimens of the Red Goshawk Erythrotriorchis radiatus. II. Morphology, biology and conservation status in eastern Australia.  Sunbird 23, 75-89.

Marchant S, Higgins PJ, (Eds) (1993) ‘Handbook of Australian, New Zealand and Antarctic birds( Vol. 2).’ (Oxford University Press: Melbourne)

NSW Field Ornithologists Club (1988-2007) NSW annual bird reports and rare bird reports, published annually in Australian Birds.

NSW NPWS (2002) ‘Approved recovery plan for the Red Goshawk (Erythrotriorchis radiatus).’ (NSW NPWS: Hurstville)