Bird flu could hit Northeast China's Heilongjiang Province in the spring as migratory birds stop in there during their annual migration, government officials and ornithologists warned.
No cases linked to migratory birds have been reported so far.
China has reported 12 human cases of bird flu nationwide since late last year, including eight deaths.
Millions of birds from southern China, Southeast Asia and European countries fly over the province on the way to Russia, Mongolia and Japan from early March.
That puts the province in danger of bird flu outbreaks, from bird droppings, said forestry department officials.
Migratory birds are a key transmission source.
The province has been on high alert against the threat and is increasing surveillance by adding more observation posts where migratory birds are likely to rest, such as Zhalong and Xingkai Lake, two nature reserves.
The province established 12 national and 40 provincial observation posts.
In Zhalong, China's largest red-crowned crane breeding center, all birds raised in captivity are vaccinated against the virus. Emergency quarantine areas have been prepared.
The province's dense river systems and vast plains make it ideal for birds to rest during migrations.
Unlike domestic poultry, which die almost immediately after infection, migratory birds, especially waterfowl, can survive for several weeks.
This means virus spread along migratory routes.
This is the time when birds congregate for migration, and if just one fowl is infected, the whole route can be tainted by their excretions or droppings.
Quarantine authorities, meantime, have banned the import of pet birds and wild birds from countries that have recorded cases of H5N1 bird flu.
In an emergency circular the General Administration of Quality Supervision, Inspection and Quarantine issued on Monday, officials urged better supervision and inspection at ports.
The administration has revoked import licenses for the entry of birds or related products from avian flu-hit countries.
The moves were made as many countries in Asia, Africa and Europe reported outbreaks of the disease, including Kuwait, Italy, Germany, Iran, France and Egypt.
The administration also ordered quarantine departments at key ports to screen people from those countries who are feverish or coughing.
(Xinhua)