The estuarine ecosystems of Sydney Olympic Park provide habitat for migratory shorebirds – a group of birds that forage in the intertidal zones of bays and estuaries, and migrate from their breeding habitat in Siberia, Japan and Alaska to Australia for the spring and summer months.
Migratory shorebirds (also called migratory waders) breed in the northern hemisphere between May and July each year, taking advantage of the short but rich northern summer before flying southward to warmer weather and to escape the approaching winter. The sorts of birds that make this journey are plovers, sandpipers, stints, knots, oystercatchers, stilts, godwits and others. The smallest of these species, the tiny Red-necked Stint, travels 30,000 kilometres each year and weighs only 30 grams!
As migratory shorebirds fly north and then south each year they take the same route and make the same stopovers for feeding and fueling. These routes are known as 'flyways'. The Flyway that exists between the Austalasian and the Asian continents is known as the East-Asian Australasian Flyway and has a combined population total of over four million birds. When these birds reach the Sydney region, they may stay for the whole summer or, after refueling, continue southwards to Victoria, Tasmania and New Zealand.
Species of migratory shorebird recorded within the Parramatta River estuary (including Sydney Olympic Park) since 1992 are listed below. Species that most commonly occur at the Park are the Sharp-tailed Sandpiper, Curlew Sandpiper, Red-necked Stint and Bar-tailed Godwit. In recent years observed numbers from daylight surveys have been relatively low (in the order of 20 birds), but at night flocks of over 250 birds are regularly recorded, indicating that the birds rely on a matrix of habitats throughout the Parramatta river estuary.
Migratory shorebirds are typically present at Sydney Olympic Park between September and April, migrating along the East Asian-Australian Flyway from breeding sites in China, Siberia, Alaska and the east Asian mainland, to take advantage of the productive summer months in both hemispheres.
The birds feed at low tide on marine worms, crustaceans and shellfish found within estuarine mudflats, sandbars and saltmarsh. At high tide, they roost on low-lying areas with good visibility, located close to feeding sites.
Migratory shorebirds both feed and roost at Sydney Olympic Park. Their main habitats are:
Migratory shorebirds also utilise the mudflats and edges of mangrove forest at Homebush Bay, and seawalls (particularly along the River Walk near Newington Nature Reserve). In very wet weather, large numbers of Bar-tailed Godwits have been recorded foraging on waterlogged turf at Archery Park.
Migratory shorebirds and their habitat are protected under inter-grovernmental agreements including the Bonn Convention (Convention on Migratory Species) and the Convention on Conservation of Biological Diversity, and agreements with the governments of Japan, Korea and Republic of Korea (JAMBA, CAMBA & ROKAMBA) which relate specifically to the protection of migratory birds. The agrements commit the Governments of each country to the protection of migratory bird habitat by actions including preservation and enhancement of their habitats and encouraging their conservation. An Action Plan has been developed for the conservation of migratory shorebirds in the East Asian-Australasian Flyway for the period 2006-2010. The Action Plan focuses on the development of a shorebird site network, appropriate management of these sites, and increasing the current knowledge base in relation to migratory shorebirds.
All of the migratory shorebirds that occur at Sydney Olympic Park are protected under the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 as ‘matters of national environmental significance’.
The Park’s habitats are part of a network of migratory shorebird habitat within the Parramatta River estuary. Birds move between these habitats in response to tide, feeding conditions and disturbance. Other parts of this network include Mason Park wetlands, Hen and Chicken Bay, Iron Cove and Ermington Bay. All of these sites have an important role in meeting the habitat needs of migratory shorebirds over the summer migration.
As well as supporting migratory shorebirds that are resident in the Parramatta River estuary over the summer months, the Park is also thought to function as a transit site for birds moving to and from summer habitats in more southerly parts of Australia. Thus the number of birds present at a particular time may significantly underestimate the number of birds reliant upon the Park’s habitats throughout the summer migration period.
Historical data shows that there has been a steady reduction in migratory shorebird populations in the Parramatta River estuary, including Sydney Olympic Park, with a sharper decrease occurring over the last 20 years. This decline has been due largely to habitat loss and disturbance. Factors outside of Australia along the Flyway are also contributing.
Tidal flushing was re-introduced to the wetland of Newington Nature Reserve from 1997 , and to the Waterbird Refuge of Badu Mangroves in 2007 to improve the ecological health of the wetlands, and their habitat value for migratory shorebirds.
Other management activities include management of wetland hydrology, removal of mangrove seedlings colonising mudflat and saltmarsh habitats, and removal of casuarina saplings that are increasingly screening the wetland and reducing sight lines. Public access to wetland perimeters, and access to the wetlands for management activities is restricted during the summer migration period.
There are at least thirty-six shorebird species that migrate from other countries to Australia. Species that have been recorded in the Parramatta River estuary and in Sydney Olympic Park since 1992 are:
Seven shorebird species have been sighted regularly at Sydney Olympic Park:
 Pacific Golden Plover |
 Rednecked Stint |
 Sharp-tailed Sandpiper |
Pacific Golden Plover |
Rednecked Stint |
Sharp-tailed Sandpiper |
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