The approach of spring brings not only the return of wild migratory birds to American shores but also the threat of avian influenza.
And this is the man whose job it is to spot it. Working on the Bering Sea at the tip of Alaska, Paul Flint, a Research Wildlife Biologist with the U.S. Geological Survey, is the point man in America's campaign against bird flu.
"We're targeting them as soon as we can from when they arrive from Asia to here," says Flint. "We're going to be on the ground in front of the bird migration waiting for the birds to arrive."
Along with Izenbek Wildlife Refuge manager Sandra Siekaniec of the U.S. Fish and Wildlife Service, and other federal and state agencies, Flint's assignment is to identify the first infected birds carrying the virus from Asia during the spring migration, and to sound the alarm.
"Alaska is one of the forefronts where it is most likely to arrive first because of its unique position as a crossroads of two international flyways: one on the Asian side of things and the other one on the North American side of things," explains Flint.
U.S. spy satellites have tracked the infected flocks, which started migrating from Asia and are now heading north to Siberia and Alaska, where they will soon mingle with flocks from the North American flyways.
"You can't build a cage around the United States," says Agriculture Secretary Michael Johanns, of the inevitably of the virus' arrival in America. "That's not possible."
Johanns tells ABC News that a bird flu outbreak in Alaska could come in as little as three weeks. That could mean further outbreaks in the lower 48 states by August.
The spread of the disease by wild migratory birds -- traveling from Asia to Africa and Europe -- has been much more rapid than first predicted. In four months, the virus has spread from 16 to 37 countries. Scientists now predict Great Britain will be next.
"We are losing our ability to forecast what's going on," says Laurie Garrett, the senior fellow for global health at the Council on Foreign Relations.
U.S. officials therefore count heavily on the early-warning system in place in Alaska, where suspect birds, including the Eastern Yellow Wagtail and the Dunlin, will be captured and tested.
Scientists here say, however, that given Alaska's remote location, it will take at least a month to confirm any outbreak, which reduces the lead time the rest of the country has to get ready.
While the virus is still not easily transmitted to humans, a report released today by Health and Human Services Secretary Michael Leavitt confirms that H5N1, a mutating type of avian influenza virus, continues to spread and change in unexpected ways. Even though the government had ordered millions of doses of vaccine, the emergence of a second, more lethal strain means another vaccine will now have to be developed.
ABC News' Maddy Sauer and Rhonda Schwartz contributed to this report.