For falconers who hunt small animals like rabbits and grouse with wild birds of prey, changing Midwest winters are also changing the sport they love.

But what has been the toll on wild birds? More than 170 species of North American wild birds – including ducks, geese, gulls, owls, eagles and others – have been infected with bird flu.

Yet by the early 1900s no wild passenger pigeons could be found ... It was not possible to reestablish the species with a few captive birds. The small captive flocks weakened and died. The last known ...

But what has been the toll on wild birds? More than 170 species of North American wild birds – including ducks, geese, gulls, owls, eagles and others – have been infected with bird flu.