As an economic report, this seems kind of suspect. But Minnesota's in the Top 5, so here we go.
One of every five Americans watches birds, and in doing so, birdwatchers contributed $36 billion to the U.S. economy in 2006, the most recent year for which economic data are available.
States with the highest birding participation rates: Montana (40 percent), Maine (39 percent), Vermont (38 percent), Minnesota (33 percent) and Iowa (33 percent).
I think there's a great case to be made that tourism connected to bird watching pump's dollars in to selected Minnesota economies.
But the Fish & Wildlife report bar is pretty low. You're basically defined as a birder if you try to identify birds in your yard. People who notice birds while cutting their lawn don't count. And that zoo trip won't help you either.
More interesting to me is another Fish & Wildlife report showing Minnesotans among the top states for photographing birds. About 12 percent of us 16 and older were interested enough in birds to pull out the camera (.pdf page 19).