HONG KONG (Reuters) - A Hong Kong theme park is to shut itsaviaries for three weeks following the discovery of a wildheron suspected of dying from bird flu.

The bird was found on Monday in a remote area of OceanPark, on the south coast of Hong Kong Island.

"As a precautionary measure, the walk-in aviaries in OceanPark will be temporarily closed to visitors for 21 daysstarting tomorrow," said a spokesperson with Hong Kong´sAgriculture, Fisheries and Conservation Department.

Ocean Park, a conservation-focused theme park with pandas,dolphins, birds and rollercoasters, attracted nearly 5 millionvisitors last year, proving more popular than the strugglingHong Kong Disneyland.

Spokeswoman Christine Lau said the rest of the park wouldoperate normally and the aviary closures were a precautionarymeasure, with the 900 birds in its collection not having shownany symptoms of bird flu.

Epidemiologists fear the H5N1 strain, which remains mainlyan animal disease but has infected humans, could mutate to aform that spreads easily among people.

China detected an outbreak of the highly pathogenic H5N1strain of bird flu in poultry in Tibet earlier this week.

(Reporting by James Pomfret; Editing by Nick Macfie)