The Washington Post is reporting that, "The lethal strain of H5N1 bird flu found in Nigeria this month probably got there in poultry and not through the movement of wild birds." 

The article, by David Brown, quotes Billy Karesh of the Wildlife Conservation Society in New York, with whom I collaborate through Bio Economic Research Associates:

I would never rule out wild birds. But I think we have to look at the most probable routes, and the most probable route would be poultry. How did it skip the whole Nile Delta and get to Nigeria? That kind of bothers me. Common sense would dictate that it should be all over Egypt by now.

Though I've been skeptical about transmission via traveling poultry, I can't argue with Dr. Karesh's reasoning.  Mr. Brown also writes that:

The first Nigerian cases were found at a commercial farm with 46,000 chickens, not among backyard flocks that would have greater contact with wild birds. Nigeria imports more than a million chicks a year from countries that include Turkey, where H5N1 appeared last fall, and China, where it has circulated for a decade.

So there is at least trade in poultry from Asia towards Nigeria, and perhaps also from Asia towards Turkey, though I am still checking into the latter possibility.  But even if shipping of poultry turns out to explain the appearance of the virus in Turkey, it seems to be showing up in wild birds first in other countries, for example last week in Italy, Greece, and Bulgaria, and just this week in Germany, Austria, and Iran.

Which leads me to think we will see the virus all over Western Europe in a matter of weeks.  Of course, nobody still has any idea how this is going to turn out in the long run.