Gould's Petrel Pterodroma leucoptera leucoptera - vulnerable species listing

NSW Scientific Committee - final determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list Gould’s Petrel Pterodroma leucoptera leucoptera (Gould, 1844) as a VULNERABLE SPECIES in Part 1 of Schedule 2 of the Act, and as a consequence, to omit reference to the Gould’s Petrel Pterodroma leucoptera leucoptera (Gould, 1844) from Part 1 of Schedule 1 (Endangered species) of the Act. Listing of vulnerable species is provided for by Part 2 of the Act.

 

The Scientific Committee has found that:

 

1. The Gould’s Petrel Pterodroma leucoptera leucoptera (Gould, 1844) (family Procellariidae) is an endemic Australian gadfly petrel, described by Marchant and Higgins (1990) as follows: “Forehead white but freckled with black, merging into sooty brown to sooty black crown and nape. Dark crown- and nape-feathers extend forward to join very dark, suborbital patch, making sides of face appear blackish, contrasting strongly with white area at base of bill. Upperwing, dark brownish-grey; dark primaries and greater coverts form indistinct open M-mark linked across lower back primaries, brown-black with white wedge at base of inner webs. Secondaries, grey with white inner webs. Mantle and back, blue-grey to dark grey; rump and upper tail-coverts, darker. Tail, grey tinged with brown, darkening at tip. Outermost tail-feather has inner web grey to brownish grey, except for off-white basal half. Chin, lores and rest of underparts, white, although dark-grey feathers extend from nape to form large patch on sides of breast and rarely may almost form a collar across throat. Underwing, white with dark remiges and dark leading-edge to outerwing, angling in at carpal joint to form prominent blackish diagonal carpal bar across secondary coverts. This underwing bar is much more pronounced than in Stejneger’s P. longirostris, which is otherwise similar; Cook’s P. cookii, and Pycroft’s P. pycrofti Petrels also have much less black on underwing but are pale-headed; pattern is less extensive than in Black-winged P. nigripennis, Chatham P. axillaris and Bonin P. hypoleuca Petrels. Bill black. Iris, dark brown. Legs and feet and upper webs, off-white; toes, joints, lower webs and claws, dull black.”

 

2. Gould's Petrel (Pterodroma leucoptera leucoptera) is one of three currently recognised subspecies of P. leucoptera. The subspecies are all morphologically quite similar and as far as is known have similar general breeding habit. The two non-Australian subspecies P.l. brevipes (the Collared Petrel) and P.l. caledonensis (New Caledonian Petrel) occur in Fiji and New Caledonia respectively. Other close relatives include P. cookii (Cook’s Petrel), P. longirostris longirostris (Stejneger’s Petrel) and P. l. pycrofti (Pycroft’s Petrel) (Marchant & Higgins 1990; DEC 2006b).

 

3. The distribution of Gould’s Petrel at sea is unknown, but believed to be in sub-Antarctic waters between Macquarie Island and Tasmania (observational data Eric Woehler, Australian Antarctic Division 2001).

 

4. The breeding sites of Gould’s Petrel are restricted to two islands at the entrance to Port Stephens on the mid-North Coast of New South Wales (Priddel & Carlile 1997a). The main breeding site is Cabbage Tree Island (John Gould Nature Reserve). A smaller population occurs on Boondelbah Island, 1.4 km to the south. The existence of other breeding sites is unlikely due to specific requirements for nesting. Gould’s Petrel nests mostly in natural rock crevices among the rock scree of the islands.

 

5. Cabbage Tree Island (John Gould NR) and Boondelbah Island are both gazetted Nature Reserves under the National Parks and Wildlife Act 1974. Cabbage Tree Island was declared Critical Habitat for the species in 2006 (DEC 2006a). Public access is restricted at both breeding islands.

 

6. During mid to late September the Gould’s Petrel arrive on the islands to breed colonially, often with nests clumped less than 1 m apart (D’Ombrain 1943). This bird is monogamous and pair bonds appear to be longstanding; pairs use the same nest site year after year (Priddel et al. 2006). They lay eggs usually over a six week period starting in early November. A single egg is laid, which is not replaced if lost. Incubation takes 49 days with each parent taking shifts of around 16 - 17 days. The chick is brooded for one or two days and both parents then share the responsibility of feeding the chick. The young remain in the nest for about 13 weeks, achieving weights of around one and a half times that of their parents. Fledglings depart the island from late March to early May and it is believed that young birds remain at sea for several years (DEC 2006b).

 

7. When first described by Gould 1844, from a Cabbage Tree Island specimen, it was reported that this species was “breeding in great numbers”. In 1970 Fullagar (1976) estimated the population of Cabbage Tree Island to be about 2000 individuals. Surveys conducted from 1989 to 1992 estimated the annual average number of breeding pairs had decreased to 220 (Priddel et al. 1995). Recovery actions undertaken since 1993 have resulted in the total number of mature individuals increasing. The current estimated number of breeding pairs on Cabbage Tree Island is between 800 and 1000, and increasing (Priddel and Carlile 2007).

 

8. The second breeding colony on Boondelbah Island was discovered in 1992 and estimated to contain 12 nesting pairs (Priddel & Carlile 1997a). A translocation program was undertaken in 1999 and the number of individuals breeding on Boondelbah Island now is around 30-40 pairs (Priddel & Carlile unpublished data).

 

9. Based on recent estimates of the number of breeding pairs, the current total number of mature individuals of Gould’s Petrel is estimated to be approximately 1650 to 2100 (Priddel & Carlile unpublished data).

 

10. There is little information available on threats to the species at sea; however, a decline in breeding success and fledgling production in 1995-96 was coincidental with a major fish kill in eastern Australia (Priddel and Carlile 1997b). The population increased markedly after the eradication of rabbits from Cabbage Tree Island in 1997 (Priddel et al. 2000). Other potential land-based threats on Cabbage Tree Island (predation by Pied Currawong and Australian Raven and entanglement in the sticky fruits of the Birdlime Tree) are now subject to ongoing mitigation measures (DEC 2006b). The establishment of a second population, on Boondelbah Island, has further safeguarded the subspecies (Priddel et al. 2006). There are currently no active threats to the Boondelbah Island population (Priddel and Carlile unpublished data). However, the species remains dependent on ongoing conservation actions.

 

11. Despite these significant conservation efforts, the Gould’s Petrel remains threatened by stochastic events because of its very highly restricted distribution. Events such as severe storms or fires could have substantial impacts on the population and its habitat. The close proximity of breeding islands to urban areas on the mainland also puts these petrels at risk of human impacts such as vandalism, fire or introduction of pest species. Over fishing of prey species also represents a potential threat. The lack of suitable colonisation sites to the south may also limit the adaptive response of the species to climate change.

 

12. Gould’s Petrel Pterodroma leucoptera leucoptera (Gould, 1844) is eligible to be listed as a Vulnerable species as, in the opinion of the Scientific Committee, is facing a high risk of extinction in NSW in the medium-term future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:

Clause 18:

The geographic distribution of the species is observed, estimated or inferred to be very highly restricted such that it is prone to the effects of human activities or stochastic events within a very short time period.

 

Dr Richard Major

Chairperson

Scientific Committee

 

Proposed Gazettal date: 31/07/09

Exhibition period: 31/07/09 - 25/09/09

 

References:

 

Department of Environment and Conservation (NSW) (2006a) ‘Declaration of critical habitat for Gould’s petrel (Pterodroma leucoptera leucoptera)’ (Pursuant to sections 44 and 47 of the Threatened Species Conservation Act 1995). Department of Environment and Conservation (NSW), Hurstville, NSW.

 

Department of Environment and Conservation (NSW) (2006b) ‘Gould’s petrel (Pterodroma leucoptera leucoptera) Recovery Plan’. Department of Environment and Conservation (NSW), Hurstville, NSW.

 

D’Ombrain AF (1943) The Cabbage Tree Island colony in the 1941-42 season. Emu 42, 156-159.

 

Fullagar PJ (1976) Seabird islands No. 35: Cabbage Tree Island, New South Wales. Australian Bird Bander 14, 94-7.

 

Gould J (1844) Procellaria leucoptera. Annals and Magazine of Natural History 13: 364.

 

IUCN (2008) ‘Guidelines for using the IUCN Red List Categories and Criteria. Version 7.0.’ (Standards and Petitions Working Group of the IUCN Species Survival Commission Biodiversity Assessments Sub-committee: Switzerland)

 

Marchant S, Higgins PJ (1990) Handbook of Australian, New Zealand and Antarctic Birds, Vol. 1A. Oxford University Press, Melbourne.

 

Priddel D, Carlile N (1997a) Boondelbah Island confirmed as a second breeding locality for Gould's petrel Pterodroma leucoptera leucoptera. Emu 97, 245-8.

 

Priddel D, Carlile N (1997b) Conservation of the endangered Gould's petrel Pterodroma leucoptera leucoptera. Pacific Conservation Biology 3, 322-29.

 

Priddel D, Carlile N (2007) Population size and breeding success of Gould's petrel Pterodroma leucoptera leucoptera on Cabbage Tree Island New South Wales 1996-97 to 2005-06. Corella 31, 79-82.

 

Priddel D, Carlile N, Davey C, Fullagar PJ (1995) The status of Gould's Petrel, Pterodroma leucoptera leucoptera, on Cabbage Tree Island, New South Wales. Wildlife Research 22, 601-10.

 

Priddel D, Carlile N, Wheeler R (2000) Eradication of European rabbits(Oryctolagus cuniculus) from Cabbage Tree Island, NSW, Australia, to protect the breeding habitat of Gould's petrel Pterodroma leucoptera leucoptera. Biological Conservation 94, 115-25.

 

Priddel D, Carlile N, Wheeler R (2006) Establishment of a new breeding colony of Gould's Petrel Pterodroma leucoptera through the creation of artificial nesting habitat and the translocation of nestlings. Biological Conservation 128, 553-63.

Page last updated: 28 February 2011