migratory risks huge

Epidemiology of bird flu viruses
Natural hosts
Migratory water birds, especially wild ducks, are the natural hosts of bird flu

They do not show clinical disease.
The virus colonises the intestinal tract and is spread in the faeces
They act as a reservoir for the infection of other species.
Wild birds introduce the virus onto poultry farms through:

Direct contact with domestic poultry.
Faeces – the avian influenza virus survives for a long time in faeces.
Contamination of drinking water.


HOWMANY BIRDS MIGRATE TO AUST? READ BELOW


Flyways are broad corridors used by migrating birds, they are like imaginary highways in the sky. For shorebirds eight Flyways have been defined in the world. In Europe and Asia there are five Flyways. These are, (from East to West), the East Asian-Australasian, the Central Asia/India, the West Asia/Africa, the Mediterranean/Black Sea and the East Atlantic Flyways. In the Americas there are three Flyways. These are the Atlantic, the Mississippi and the Pacific Flyways.

Some species or individuals cross from one Flyway to another. So in the East Asian-Australasian Flyway Ruffs breeding in East Siberia are known to migrate westwards to Europe and Africa joining the East Atlantic Flyway. Grey Phalaropes and Pectoral Sandpipers breeding in East Siberia mainly migrate to spend the non-breeding season in South America in the Pacific Flyway.
Some birds are thought to fly the whole route in one flight but most birds stop along the way. These places are called stop-overs or staging areas. New studies show that not all the staging areas are on the flyways, some are detours for birds who need a rest or more food. The staging areas occur all the way down the flyway in many different countries and include many different habitats. There are different staging areas for different species of birds. Within the staging areas there are places for feeding (usually at low tide) and places for resting (or roosting), usually at high tide. When people are managing these places for shorebirds they need to make sure there are spaces suitable for the birds for feeding and for roosting.

The numbers of waders in the East Asian-Australasian Flyway are unknown. They are probably a minimum of 4 million migratory waders. Within Australia there are estimated a minimum of 1 million resident waders and a minimum of 2 million migratory waders.