Pine Siskins in 2010-2011?

I received an intriguing email "telegram" yesterday from Cary Naturalist Mark Johns: "Winter birds in place this week: white-throated sparrow, yellow-bellied sapsucker, golden-crowned kinglet, ruby-crowned kinglet, pine siskin". Most of these species are regular winter guests but the last caught my eye. We can get this species here in the Piedmont, but the odds are pretty slender that Average Joe BirdFeeder will see any in a given winter. We had a very good irruption as recently as 2008-09 but last winter was a dud for me. I had not expected any this year based on predicted temperature reports for the north. But here we are, sightings in Cary not many miles away. Obviously I will be watching my tube feeders intently this winter in hopes of seeing these interesting visitors.