Shorebirds, also known as waders, are a diverse group of birds commonly seen feeding in intertidal areas or on the fringes of freshwater wetlands. They generally have long legs in relation to their body size, no webbing on their feet and they do not swim. The shape and size of their bill gives a clue to their preferred diet and habitat. The long probing bill of the eastern curlew is ideal for fishing out worms and crustaceans from deep mud whereas the short, stubby bill of the ruddy turnstone can flip aside stones and shells on a rocky foreshore to expose food.
Shorebirds make up about ten percent of Australia's species of birds. Most breed in the Northern Hemisphere and around 40,000 shorebirds migrate to Moreton Bay Marine Park each year. Many others reside permanently in the marine park.
Moreton Bay Marine Park 's wetlands are extremely critical for shorebirds. This importance has been further acknowledged through its listing as a Ramsar site - an international treaty providing for the conservation of wetlands and their resources around the world.
Shorebirds fly through extreme weather, avoiding predators as they navigate a chain of wetlands from the northern to southern hemispheres. Moreton Bay Marine Park is an important habitat in the East Asian-Australasian Flyway, which is one of only eight international routes taken by migratory birds. The marine park is often the first site shorebirds use in Australia on their southern journey and the last site before they return north.
Shorebirds travel remarkable distances of up to 25,000 kilometres each year. They breed in areas where melting snow brings masses of insects, providing a vital food source for self-feeding chicks. Once breeding is complete, and before the onset of the arctic winter, the adults and their chicks begin their return journey to the plentiful feeding grounds in the south.
Migrating shorebirds need huge amounts of energy to complete their journey. One of the best-studied species, the eastern curlew, dramatically builds up its body weight just prior to migration. During its 13,000 kilometre flight from Siberia to Australia it will burn 40 percent of its body weight. This is equivalent to an 80 kilogram person running 16 million kilometres almost non-stop and losing 32 kilograms, twice a year!
Each year, around 15 percent of the migrating shorebirds that visit Moreton Bay Marine Park in the summer remain for the whole year. This includes birds that are too young to breed or adults that are too weak for the northern journey.
Moreton Bay Marine Park has around 3,500 resident shorebirds, representing 16 species. These birds breed in and around the marine park. Some of the most recognisable species include the pied oystercatcher, the bush stone-curlew and the red-capped plover. The beach stone-curlew and the sooty oystercatcher are less common and are of international and national significance because ongoing disturbance has drastically reduced their numbers. In Queensland, the vulnerable beach stone-curlew and the rare sooty oystercatcher are just two of the marine park's species that are doing it tough.
When it is time for resident shorebirds to breed, they build their nests just above the high tide line of beaches and rocky shorelines. This exposes them to damage from vehicles driving above high tide lines and from people camping on dunes. Each year many young shorebirds and some adults are killed because of beach traffic.
Shorebirds' lives are driven by the tides
At low tide, regardless of day or night, shorebirds feed constantly - pecking and probing for worms, insects and crustaceans. With their highly variable and specialised bills they feed around intertidal flats, beaches, rocky headlands and along the fringes of freshwater wetlands.
As the incoming tide covers these feeding areas, they begin to congregate in large numbers at relatively safe roost sites nearby. These roost sites provide areas where they can interact, preen, digest their food and rest while waiting for the ebbing tide to again expose their feeding areas. During particularly high spring tides, all the shorebirds of Moreton Bay Marine Park crowd together on a limited number of higher elevation roost sites. Any disturbance during this time has major consequences - shorebirds may even be forced to abandon their roost sites because of disturbances.
You can help protect shorebirds
Shorebirds are very easily disturbed by close activity. A disturbance is any action that interrupts the breeding, feeding or resting of shorebirds. For example, causing a shorebird to take flight represents a significant disturbance. When shorebirds take flight they use critical energy that is required for migration and breeding. Repeated disturbances and disturbances that occur before or after migration are particularly damaging for shorebirds. Without sufficient energy reserves shorebirds may be unable to complete their migration or breed.
Dogs in particular disturb shorebirds. In local government areas adjoining Moreton Bay Marine Park dogs must be on a leash at all times except in designated "off leash" areas. Penalties apply for not complying with this requirement.
QPWS (2005) Shorebird management strategy - Moreton Bay, Environmental Protection Agency, Brisbane
QPWS (2005) Shorebirds in Moreton Bay: Shorebird guide, Environmental Protection Agency, Brisbane
Shorebirds fly up to 25,000 kilometres on their annual trip to Moreton Bay Marine Park.