David pointed out this message from Bird Chat on winter finches:
We are experiencing the biggest winter finch irruption since the "superflight" of 1997-1998, when many boreal finches went well beyond their normal ranges. The cause is the largest tree seed crop failure in a decade across more than 3200 km (2000 mi) of boreal forest from Saskatchewan into Quebec. Today in Toronto, I had a Pine Grosbeak, Evening Grosbeaks, Common Redpolls, Pine Siskins and Purple Finches migrating along the shoreline of Lake Ontario. Boreal winter finches are being reported in many areas of southern Ontario and the United States, where some species such as Pine and Evening Grosbeaks haven't been seen in years. There is no telling how far south this "superflight" will go.Watch those feeders!
For background see my previous post on Ron Pittaway's predictions of a large finch flight this winter.
Update: I have not seen any boreal birds yet myself this fall, but apparently upstate New York is flooded with them - bohemian waxwings and northern shrikes!
The Brooklyn Paper covers invaders from across the border.