What does avian flu mean for wild birds and biodiversity?

Bird flu puts wild birds at risk in two ways: from the virus and from humans trying to control the virus. A United Nations (UN) task force on avian flu points out that wild birds are not the main cause of the deadly avian flu virus. Often overlooked major contributors to the problem include: rural poultry practices, the movement of domestic poultry, live poultry markets and intensive factory farming.

Wild birds do play a role, however. The WHO explains that while we don't understand exactly how migratory birds are involved in transmitting the highly pathogenic avian virus, there is "considerable circumstantial evidence" that migrating birds can introduce less pathogenic versions of the disease to poultry flocks. Once the farmed poultry get infected, the disease can mutate into the deadly form.

The deadly strain of avian flu, even if it never turns into a human pandemic, could have serious impacts on bird diversity. "In May, a single outbreak in China killed up to a tenth of the world's bar-headed geese," writes Scott Weidensall in The New York Times. The UN task force identified 36 already-threatened water birds that seem vulnerable to the disease. A full-scale international review of the effects of avian flu on biodiversity is being conducted in March, 2006. Sign up for the meeting's e-forum.