Experts have began setting up a bird flu early warning system by mapping routes that are taken by migrating species and places where they rest during their annual travel, United Nations officials said Sunday.

Migrating birds have spread the deadly H5N1 strain of avian flu from Asia to other parts of the world, scientists say.

Health experts say the H5N1 strain could be the source of the next human flu pandemic if it mutates into a form easily passed between humans. Most of the at least 67 human deaths from bird flu have been traced to contact with sick birds.

Details of the warning system were announced at an international wildlife conference in Kenya's capital, Nairobi. The exact workings of the system have yet to be ironed out.

The pilot project is expected to be operational in six months and the whole plan should be up and running in two years, said Marco Barbieri of the U.N. Convention on the Conservation of Migratory Species of Wild Animals.

The agency is developing the system with the help of the U.N. Environment Program, which has offered $30,000.

"You don't need a lot of money to do this because a lot of information is out there, scattered in a lot of places. ... It is simply a matter of pulling it all together into a centralized system," said Nick Nuttall, spokesman of the United Nations Environment Program.

The information will be used to warn countries and communities of the arrival of wild birds that could be infected. This will enable local authorities to issue advice to those in areas at risk, Nuttall said.

Britain's Biodiversity Minister Jim Knight said the system would also enable experts to recommend that farmers move poultry away from key wetlands to minimize cross infections from migratory birds, to offer advice on hygiene and how hunters should handle harvested birds.

The timing of migrations can vary from year to year and from season to season depending on numerous factors including weather and climatic conditions.

An efficient early warning system will have to feed in observations from sites throughout the world on when water birds are starting their migration and relay this to countries likely to receive these species.

"There are also important gaps in our scientific knowledge about fly-ways and migratory routes for some species. We need to urgently bridge that gap too. In doing so I believe this initiative can make a valuable contribution to the worldwide effort to deal with this threatened pandemic," the U.N. environment chief Klaus Toepfer said.

Experts from Wetlands International, Birdlife International and the International Wildlife and Game Federation are also expected to be part of the early warning scheme.