Bird-lovers in Australia are casting anxious eyes to an outbreak of avian influenza which is decimating bird populations in the northern hemisphere and South America.
The bird flu has not reached Australia yet but the convenor of Birdlife Tasmania, Eric Woehler, says it is just a matter of time before it arrives here.
Dr Woehler said that the current outbreak and spread of bird flu in Eurasia was of serious concern to researchers and conservationists in the Southern Hemisphere.
“We are seeing the spread ever southward, with recent reports of infected waterbirds from South-east Asia,” he said. “At some point, the flu will reach Australia and, based on the scale of bird deaths we have seen in the Northern Hemisphere, it is likely that many of our waterbirds will be affected.”
Among species at risk is the black swan. Because of Australia’s isolation, such endemic birds have not had an opportunity to build immunity against highly infectious diseases rampant in other continents.
Bird experts in Britain, meanwhile, are at present bracing themselves for a return of the virus which has already wiped out bird populations across the country. They are keeping a close watch on migrating birds as they arrive at the start of the northern breeding season.
The current bird flu epidemic is caused by the H5N1 strain of the virus, which originated in poultry farms in Asia and has since spread round the globe, with infected migrating birds playing a pivotal role in its spread.
There were concerns at the end of the Australian summer that waders arriving from breeding grounds in the far northern hemisphere might bring the disease with them but monitoring of these birds has found they are so far disease-free. Migratory shorebirds fly what is known as the East Asian-Australasian flyway, traversing countries such as China which have an extensive poultry industry.
The Guardian newspaper in Britain reports that the leading bird-watching organisation in the UK, the Royal Society for the Protection of Birds, has said the outlook for 2023 looks particularly “grim”.
The disease has had a growing impact on wild birds in Britain over the past two years with 65 species being infected.
About 16,000 barnacle geese died on the Solway Firth in south-west Scotland last winter and 11,000 of the 150,000-strong gannet colony at Bass Rock in east Scotland have been killed. In Israel, 5000 grey cranes died during an outbreak there.
The disease in some countries is reported to have spread to mammals. In Britain, otters and foxes have died and in Chile it has spread to sea lions and marine otters, along with killing more than 700 Humboldt penguins.
Although mammals have been affected, the bird flu virus does not normally infect humans. However, sporadic human infections have occurred and a child in Cambodia is reported to have died of the disease earlier this year.