Australian wetlands—important feeding grounds for non-breeding migratory shorebirds
Australian coastal and freshwater wetlands host around two million visiting migratory shorebirds that come here from Arctic regions during the non-breeding season to feed each year. There are thirty-six species that arrive around September, reaching ‘staging areas’ such as Roebuck Bay and Eighty Mile Beach (both internationally important Ramsar wetlands) in north-western Australia and the Gulf of Carpentaria in Queensland. They arrive after an amazing migration of up to 13,000 km, from the northern hemisphere. The birds then disperse across Australia, reaching the south-eastern states by October. Many take advantage of ephemeral wetlands across inland Australia and others spread out along the coastline.
By March, the birds that have previously dispersed across the country return to their staging areas, forming large flocks and feeding almost around the clock to accumulate energy reserves for their northward migration.
From October to March if you visit any coastal wetland or intertidal area you might be able to see these amazing little birds—Greater Sand Plovers, Bar-tailed Godwits, Red-necked Stints and Eastern Curlew feeding on exposed sand flats at low tide. If you were in Roebuck Bay in March you could expect to see thousands of migratory shorebirds feeding or resting close to shore. But don’t get too close, shorebirds don’t like to be disturbed by humans or dogs when they are trying to feed and rest.
The Arctic tundra—where migratory shorebirds breed
Migratory shorebirds breed in the northern summer in the Arctic tundra of Russia and Alaska and other northern hemisphere locations such as Mongolia and northern China. When the young are just six weeks old, most of the parents leave on their journey to the southern hemisphere. The chicks must feed and grow quickly so they can fly south when they are about eight weeks old, to avoid freezing as the snow and icy Arctic winds set in. The young birds increase in mass by up to 80 per cent, just over half of which is fat. Before the young birds leave, other transformations occur – their feeding organs shrink, their heart grows and their blood thickens to equip them for their long-haul journey. Once they set off on their six to eight week journey to their non breeding areas in Indonesia, Papua New Guinea, Australia and New Zealand, the migratory shorebirds fly nonstop for days at a time before landing to rest. At the half way point most need to stop to put on more fat to fuel their journey. It is important that they have large areas of suitable habitat, such as food-rich intertidal flats to stop at along the way and also on their return journey.
The East Asian—Australasian Flyway
The pathway along which migratory birds fly between the Arctic and Australia is the East Asian-Australasian Flyway (EAAF). In the face of ever-increasing human development and loss of habitat some migratory shorebird populations along the EAAF are decreasing, such as the critically endangered Eastern Curlew and Great Knot. To ensure the survival of healthy flyway populations it is critical that important migratory shorebird feeding and staging areas along the flyway are protected from threats such as habitat loss and modification from urban, industrial and agricultural development, pollution, weeds, invasive species and water regulation.
The Convention on Wetlands of International Importance (Ramsar Convention) was the first modern treaty between nations aimed at conserving natural resources. In 1974 Australia designated the world’s first Wetland of International Importance: Cobourg Peninsula in the Northern Territory. Australia now has 65 Ramsar wetlands that cover more than 8.3 million hectares.
Map: The East Asian-Australasian Flyway
In 2007 a female bar-tailed godwit fitted with a small satellite device took off from Alaska on 30 August and was tracked to New Zealand where she landed on 7 September, having flown 11,680 km in eight days. The bird, known as ‘E7’, from her coded leg flag, probably only weighed about 600 g.
You may have seen shorebirds with metal leg bands or coloured flags. Metal bands are used to identify individual birds (they need to be captured by researchers to read the information on the band). Leg flags are used on migratory shorebirds to show the area where they were banded and can be seen quite easily with binoculars. Reported sightings of leg flag colours provide information about the routes flown by migratory shorebirds and the distances they fly. This information helps scientists to understand their biology and can help in their protection and conservation.
Protection of wetlands and migratory shorebirds
Australia has implemented a number of measures domestically and with international partners that help to support migratory shorebird populations and their wetland habitats. These include:
- the Environment Protection and Biodiversity Conservation Act (EPBC Act), which is the Australian Government’s key environmental legislation:
- matters of national environmental significance including migratory species, threatened species and internationally important (Ramsar) wetlands are protected
- a Wildlife Conservation Plan for Migratory Shorebirds
- conservation advice for threatened migratory shorebirds
- bilateral migratory bird agreements with Japan, China and the Republic of Korea
- membership of international conventions including the Convention on Migratory Species (Bonn Convention) and the Convention on Wetlands of International Importance (Ramsar Convention)
- the East Asian-Australasian Flyway Partnership
- a network of protected areas including Ramsar Wetland sites and a Flyway Site Network.