NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. The Curlew Sandpiper Calidris ferruginea (Pontoppidan, 1763) (family Scolopacidae) is a small (18-23 cm), highly-gregarious, migratory shorebird with a medium-length, down-curved bill and longish black legs (Pizzey 1980). During most of their time in Australia, adult birds are in non-breeding plumage, which is a nondescript mottled grey above and paler below, with indistinct white eyebrows and a white rump. In flight there is a white line along the centre of the upper-wings (Higgins & Davies 1996). In breeding plumage the face and under-parts are chestnut, and the upperparts are mottled chestnut and black. The down-curved bill distinguishes it from other similar-sized sandpipers. Many other shorebirds of this size have similar colouration and are easily confused with the Curlew Sandpiper, but they differ in bill shape, length or colour; leg colour or length; and some lack a white wing bar or white rump.
2. The Curlew Sandpiper is distributed around most of the coastline of Australia (including Tasmania) (Higgins & Davies 1996; Geering et al. 2007). It occurs along the entire coast of NSW, particularly in the Hunter Estuary, and sometimes in freshwater wetlands in the Murray-Darling Basin. It generally occupies littoral and estuarine habitats, and in New South Wales is mainly found in intertidal mudflats of sheltered coasts. It also occurs in non-tidal swamps, lakes and lagoons on the coast and sometimes the inland. It forages in or at the edge of shallow water, occasionally on exposed algal mats or waterweed, or on banks of beach cast seagrass or seaweed. It roosts on shingle, shell or sand beaches; spits or islets on the coast or in wetlands; or sometimes in salt marsh, among beach cast seaweed, or on rocky shores. Curlew Sandpipers are omnivorous, feeding on worms, molluscs, crustaceans, insects and some seeds.
3. The Curlew Sandpiper breeds in Siberia and migrates to Australia (as well as Africa and Asia) for the non-breeding period, arriving in Australia between August and November, and departing between March and mid-April. Birds that migrate to Australia fly overland across Siberia and China, then through India, Burma, Malaysia, Thailand and Indonesia, arriving in north-western Australia. Some birds then fly overland to south-eastern Australia, with a relatively small population travelling to New South Wales. On the northern return flight, birds take a more easterly route, flying along the south-eastern and eastern coasts of China (Higgins & Davies 1996). Large numbers of Curlew Sandpipers use the western side of the Yellow Sea as a “staging ground” where they stop to feed and build up their energy reserves before continuing their migration (Clive Minton, in litt. 2010). In their breeding grounds they nest in open tundra amongst marshy depressions and pools resulting from melting permafrost and snow, where they feed on superabundant insects (Birdlife International 2011). Birds breed at 2 years of age and the oldest recorded bird is 19 years old. Most birds caught in Australia are between 3 and 5 years old (Australian Wader Study Group in litt. 2010), indicating a generation time of approximately 4 years. An alternative generation time of 7.6 years has been estimated based on annual survival rates of congeneric species (Garnett et al. 2011).
4. The global population of the Curlew Sandpiper has been estimated at 1,800,000 – 1,900,000 with an increasing overall population trajectory, although some populations are declining (Birdlife International 2011). The population in the East Asian-Australasian flyway was estimated at 180,000 birds in 2008 with an Australian population of 118,000 (Bamford et al. 2008). Recent declines in the Australian population of between 50 and 79% over 23 years have been reported (Garnett et al. 2011). The most important site in New South Wales is the Hunter River Estuary, where the maximum number of birds recorded (between 1981 and 1985) was 4,000 individuals (Higgins & Davies 1996). Extensive monitoring of 36 key shorebird sites in New South Wales by the Australian Wader Study Group has documented a large decline between 1981 and 2010. Since 1998 there has been only one year in which the maximum state-wide count has exceeded 1000 individuals, and the mean yearly maximum count between 1998 and 2010 is 520 ± 230 (SD) birds. Given that the most important sites in New South Wales were monitored in this survey, it is likely that the total population in New South Wales is low, consisting of fewer than 2,500 individuals.
5. Survey data from three sources indicate that the species has undergone a large reduction in population size in New South Wales. Fitting a linear regression to the 29 years’ data collected by the Australian Wader Study Group indicates that there has been a 94% decline in maximum annual counts of the New South Wales population between 1982 and 2010. This is equivalent to a decline of 89% over three generations, the period recommended by IUCN (2010) for calculating population reduction. This decline was not correlated with rainfall. Aerial surveys of migratory shorebirds across the wetlands of eastern Australian have also detected a significant decline of small migratory shorebirds (Nebel et al. 2008). These surveys included, but did not distinguish, the Curlew Sandpiper and indicate a decline of 73% over the 24 years from 1983 to 2006. Data collected by the Birds Australia atlas project also demonstrated a significant decline in the reporting rate of Curlew Sandpipers. The species was recorded in 32 one-degree grids in New South Wales during the first national bird atlas in 1977-81 (Blakers et al. 1984), and in 19 one-degree grids in New South Wales during the second national bird atlas in 1998-2001 (Barrett et al. 2003). Its reporting rate in New South Wales declined significantly by 46% between the two atlases, and nationally by 26% (Barrett et al. 2003, 2007). However, declines based on presence/absence reporting rates are likely to underestimate population reduction of highly-gregarious species such as Curlew Sandpipers. The national data, combined with observations of substantial decline in Victoria (Clive Minton, in litt. 2010; Mike Weston, in litt. 2010), South Australia (Close 2008; Wainwright & Christie 2008), Western Australia (Rogers et al. 2009) and Queensland (Fuller et al. 2009 – cited in Garnett et al. 2011) suggest that the decline in both coastal and inland New South Wales represents a large reduction in population size rather than a distributional shift.
6. The dominant threats to Curlew Sandpipers are associated with development pressure and human disturbance in foraging sites in coastal areas, both in Australia and especially in their staging grounds during migration (Clive Minton, in litt. 2010). Their tidal feeding grounds on the Yellow Sea are undergoing a rapid rate of transformation due to land reclamation, agriculture and industry (Barter 2006, Rogers and van de Kam 2007), with about 10% of the world’s human population occupying the river catchments draining into the Yellow Sea (Nebel et al. 2008). Curlew Sandpipers are also likely to be displaced from foraging and roosting sites by heavy human recreational use of beaches, shorelines and estuaries. While this is not considered to be a problem in many parts of Australia where Curlew Sandpipers occupy remote areas (Clive Minton, in litt. 2010), it is likely to be a factor in New South Wales where the most important site, the Hunter River Estuary, is in close proximity to the major urban centre of Newcastle. Nebel et al. (2008) emphasise the importance of local threats, observing that non-migratory shorebirds experienced similar declines between 1983 and 2006 to those species that undergo migration. Major floodplain wetlands in the Murray-Darling Basin have had up to a 60% reduction in flow, and consequently 40-77% of their area has been destroyed or degraded over the past century (Kingsford & Thomas 2004; Kingsford & Porter 2009). This may have contributed to the decline in Curlew Sandpiper numbers in inland wetlands. Climate change has also been proposed as a potential threat to migratory shorebirds in their breeding grounds (Nebel et al. 2008). Average temperatures in the arctic have risen at almost twice the rate of the rest of the world and may detrimentally affect species such as the Curlew Sandpiper that nest in open tundra. Two different climate models predict losses of 41% and 70% of breeding habitat of Curlew Sandpipers by the end of the 21st century (Callaghan 2010). ‘Anthropogenic Climate Change‘ and ‘Alteration to the natural flow regimes of rivers and streams and their floodplains and wetlands’ are listed as Key Threatening Processes in New South Wales under the Threatened Species Conservation Act 1995.
7. The Curlew Sandpiper is listed as ‘Migratory’ under the Commonwealth’s Environment Protection and Biodiversity Conservation Act 1999, and is subject to the Bonn Convention on Migratory Species.
8. The Curlew Sandpiper Calidris ferruginea (Pontoppidan, 1763) is not eligible to be listed as a Critically Endangered species.
9. The Curlew Sandpiper Calidris ferruginea (Pontoppidan, 1763) is eligible to be listed as an Endangered species as, in the opinion of the Scientific Committee, it is facing a very high risk of extinction in New South Wales in the near future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2010:
Clause 6 Reduction in population size of species
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:
(b)a large reduction in population size,
based on the key indicator:
(a)an index of abundance appropriate to the taxon.
Clause 8 Low numbers of mature individuals of species and other conditions
The estimated total number of mature individuals of the species is:
(b)low,
and:
(d) a projected or continuing decline is observed, estimated or inferred in the key indicator:
(a) an index of abundance appropriate to the taxon.
Dr Richard Major
Chairperson
Scientific Committee
Proposed Gazettal date: 09/12/11
Exhibition period: 09/12/11 – 03/02/12
References:
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Barrett GW, Silcocks AF, Cunningham R, Oliver DL, Weston MA, Baker J (2007) Comparison of atlas data to determine the conservation status of bird species in New South Wales, with an emphasis on woodland-dependent species. Australian Zoologist 34, 37-77.
Barter MA (2006) The Yellow Sea – a vitally important staging region for migratory shorebirds. In ‘Waterbirds around the world.’ (Eds. Boere GC, Galbraith CA and Stroud DA) pp. 663-667. (The Stationary Office: Edinburgh)
BirdLife International (2011) Species factsheet: Calidris ferruginea (verified 11 February 2011). Blakers M, Davies SJJF, Reilly PN (1984) ‘The atlas of Australian birds.’ (Melbourne University Press: Melbourne)
Blakers M, Davies SJJF, Reilly PN (1984) ‘The atlas of Australian birds.’ (Melbourne University Press: Melbourne)
Callaghan TV (2010) Recent and projected changes in arctic species distributions and potential ranges. Section 7.3.5 of the Arctic Climate Impact Assessment. International Arctic Science Committee (verified 11 February 2011).
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Wainwright P, Christie M (2008) Wader surveys at the Coorong and S.E. Coastal Lakes, South Australia. Stilt 54, 31-47.