The appearance of the virus in Hong Kong, more active in the cooler months between October and March, is closely watched as it may indicate the level of activity of the virus in mainland China, which has a poultry population of 13 billion.

The virus is endemic in poultry in parts of Asia but experts fear it will mutate into a form that is easily passed from human to human, sparking a pandemic which could kill millions of people.

"House crows are common in Hong Kong. We have no idea if it came from elsewhere, how it was infected," the spokeswoman for the Agriculture, Fisheries and Conservation Department said.

The crow was found dead in a public refuse bin on Wednesday.

Since 2003, the virus has infected 387 people in 15 countries, killing 245, according to latest statistics from the World Health Organization.